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Tropical Cyclone NATHAN
Southern Hemisphere Summary
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Tropical Cyclone NATHAN Southern Hemisphere Summary |
WTPS21 PGTW 20150310 03:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 150 NM RADIUS OF 12.9S 149.6E WITHIN THE NEXT 06 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 25 TO 30 KNOTS. METSAT IMAGERY AT 100230Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 12.9S 149.6E. THE SYSTEM IS
MOVING SOUTHWESTWARD AT 11 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.0S
150.9E IS NOW LOCATED NEAR 12.9S 149.6E, APPROXIMATELY 205 NM NORTH
OF WILLIS ISLAND, AUSTRALIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 092339Z MHS METOP-B IMAGE DEPICT A CONSOLIDATING LOW-
LEVEL CIRCULATION CENTER (LLCC) WITH IMPROVED DEEP CONVECTIVE
BANDING. A 092341Z ASCAT IMAGE INDICATES A DEFINED CIRCULATION WITH
NUMEROUS 30-KNOT WIND VECTORS AND SOME ISOLATED 35-KNOT WIND VECTORS
OVER THE EASTERN SEMI-CIRCLE. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10-20 KNOT) VERTICAL
WIND SHEAR OFFSET BY EXCELLENT DUAL CHANNEL OUTFLOW. SEA SURFACE
TEMPERATURES ABOVE 30C ARE ALSO VERY FAVORABLE FOR FURTHER
DEVELOPMENT. GLOBAL MODELS ARE IN GOOD AGREEMENT ON FURTHER
DEVELOPMENT OF THIS SYSTEM. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1000 MB. DUE TO THE FAVORABLE ENVIRONMENTAL CONDITIONS
AND THE CONSOLIDATING LLCC, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
110300Z.//
=========================================================================
WTPS32 PGTW 20150310 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/100251ZMAR2015//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 001
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
101800Z --- NEAR 13.6S 147.5E
MOVEMENT PAST SIX HOURS - 250 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.6S 147.5E
---
FORECASTS:
12 HRS, VALID AT:
110600Z --- 13.9S 146.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 270 DEG/ 03 KTS
---
24 HRS, VALID AT:
111800Z --- 13.9S 146.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 315 DEG/ 01 KTS
---
36 HRS, VALID AT:
120600Z --- 13.7S 145.8E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 045 DEG/ 02 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
121800Z --- 13.4S 146.1E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 085 DEG/ 03 KTS
---
72 HRS, VALID AT:
131800Z --- 13.3S 147.4E
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 095 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
141800Z --- 13.6S 150.4E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 100 DEG/ 09 KTS
---
120 HRS, VALID AT:
151800Z --- 14.3S 153.9E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
102100Z POSITION NEAR 13.7S 147.3E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 221 NM
NORTH-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED WEST-
SOUTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS A CENTRAL DENSE OVERCAST FEATURE
WITH DEEP CONVECTIVE BANDING WRAPPING INTO THE LOW LEVEL CIRCULATION
CENTER (LLCC) FROM THE NORTHERN QUADRANT. A 101824Z SSMIS IMAGE
DEPICTS TIGHTLY CURVED BANDING WRAPPING INTO THE LLCC WITH THE BULK
OF CONVECTION ALONG THE NORTHWESTERN QUADRANT. THE INITIAL POSITION
IS BASED ON A MICROWAVE EYE FEATURE FOUND IN THE SSMIS IMAGE WITH
HIGH CONFIDENCE. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON A
RECENT SCATTEROMETER PASS WITH 40 TO 45 KNOT WINDS AND THE ABRF
DVORAK ESTIMATE OF T3.0. UPPER LEVEL ANALYSIS SHOWS A FAVORABLE
ENVIRONMENT WITH THE SYSTEM LOCATED NORTH OF THE RIDGE AXIS IN AN
AREA OF EXTENSIVE DIVERGENCE. ADDITIONALLY, TC 18P IS ENCOUNTERING
WEAK TO MODERATE (15-20 KNOTS) VERTICAL WIND SHEAR (VWS) AND VERY
FAVORABLE SEA SURFACE TEMPERATURES. TC NATHAN IS CURRENTLY TRACKING
WESTWARD UNDER THE INFLUENCE OF A WEAKENING SUB-TROPICAL RIDGE (STR)
LOCATED TO THE SOUTH. AS THE STR FURTHER WEAKENS, DUE TO A SHORTWAVE
TROUGH PASSING TO THE SOUTH, THE STEERING MECHANISM WILL SHIFT TO
STRONG WESTERLIES NORTH OF THE SYSTEM CAUSING IT TO TURN CLOCKWISE
AND FOLLOW AN EASTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST
PERIOD. ENVIRONMENTAL CONDITIONS WILL IMPROVE AS THE CYCLONE GAINS A
POLEWARD CHANNEL DUE TO THE AFOREMENTIONED TROUGH. VWS WILL INCREASE
SLIGHTLY TO MODERATE LEVELS TOWARDS THE END OF THE FORECAST PERIOD
LEADING TO A SLIGHT WEAKENING TREND. DYNAMIC MODEL GUIDANCE IS IN
DISAGREEMENT ON THE TIMING OF THE CLOCKWISE TURN, BUT IN GENERAL
AGREEMENT IN THE OVERALL TRACK. DUE TO UNCERTAINTY IN THE TIMING OF
THE TURN, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101800Z IS 10 FEET. NEXT WARNINGS
AT 110900Z AND 112100Z. REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS
(WTPS31 PGTW) FOR SIX-HOURLY UPDATES. THIS CANCELS AND SUPERSEDES
REF A (WTPS21 PGTW 100300).//
=========================================================================
WTPS32 PGTW 20150311 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 002
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
110600Z --- NEAR 13.4S 146.3E
MOVEMENT PAST SIX HOURS - 335 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.4S 146.3E
---
FORECASTS:
12 HRS, VALID AT:
111800Z --- 13.3S 145.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 315 DEG/ 02 KTS
---
24 HRS, VALID AT:
120600Z --- 13.0S 145.3E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 055 DEG/ 02 KTS
---
36 HRS, VALID AT:
121800Z --- 12.8S 145.6E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 090 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
130600Z --- 12.8S 146.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 090 DEG/ 06 KTS
---
72 HRS, VALID AT:
140600Z --- 12.7S 148.5E
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 095 DEG/ 11 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
150600Z --- 13.0S 153.0E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 105 DEG/ 12 KTS
---
120 HRS, VALID AT:
160600Z --- 14.2S 157.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
110900Z POSITION NEAR 13.4S 146.1E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 212 NM
NORTH OF CAIRNS, AUSTRALIA, HAS TRACKED NORTH-NORTHWESTWARD AT 04
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A CENTRAL DENSE OVERCAST FEATURE
WITH DEEP CONVECTIVE BANDING WRAPPING INTO THE LOW LEVEL CIRCULATION
CENTER (LLCC) WITH THE MAJORITY OF THE CONVECTION IN THE NORTHERN
QUADRANT. A 110340Z GCOM IMAGE DEPICTS WELL CURVED BANDING WRAPPING
INTO THE LLCC WITH THE BULK OF CONVECTION ALONG THE NORTHWESTERN
QUADRANT. THE INITIAL POSITION IS BASED ON THE MSI AND A MICROWAVE
EYE FEATURE FOUND IN THE GCOM IMAGE WITH HIGH CONFIDENCE AND THE
INTENSITY OF 45 KNOTS IS BASED ON DVORAK ESTIMATES FROM ALL
REPORTING AGENCIES. UPPER LEVEL ANALYSIS CONTINUES TO SHOW A
FAVORABLE ENVIRONMENT WITH THE SYSTEM LOCATED NORTH OF THE RIDGE
AXIS IN AN AREA OF EXTENSIVE DIVERGENCE ALTHOUGH REMAINING IN A
REGION OF MODERATE TO HIGH VERTICAL WIND SHEAR (VWS). VERY FAVORABLE
SEA SURFACE TEMPERATURES IN ADDITION TO DECREASING VWS WILL ALLOW
THE SYSTEM TO INTENSIFY AS IT TRACKS TO THE WEST UNDER THE INFLUENCE
OF A SUBTROPICAL RIDGE (STR) TO THE SOUTH OF THE SYSTEM. AS THE STR
WEAKENS BY TAU 36, TC NATHAN WILL TRACK TO THE EAST AND INTENSIFY
DUE TO A SHORTWAVE TROUGH PASSING TO THE SOUTH AND THE STEERING
MECHANISM SHIFTING TO THE STRONG WESTERLIES. UPPER LEVEL OUTFLOW
WILL INCREASE SIGNIFICANTLY, ALLOWING THE SYSTEM TO REACH A PEAK
INTENSITY OF 90 KNOTS BY TAU 72. IN THE EXTENDED FORECAST, VWS WILL
INCREASE SIGNIFICANTLY TOWARDS THE END OF THE FORECAST PERIOD
LEADING TO A SLIGHT WEAKENING TREND. DYNAMIC MODEL GUIDANCE IS IN
FAIRLY GOOD AGREEMENT IN GENERAL OVERALL TRACK. HOWEVER, DUE TO
COMPLICATED NATURE OF THE VARIOUS STEERING MECHANISMS AND TIMING OF
THE TURN, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST, LAID
CLOSE TO THE MULTI-MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 110600Z IS 14 FEET. NEXT WARNINGS AT 112100Z AND 120900Z. REFER
TO TROPICAL CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW) FOR SIX-HOURLY
UPDATES.//
=========================================================================
WTPS32 PGTW 20150311 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 003
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
111800Z --- NEAR 13.7S 145.8E
MOVEMENT PAST SIX HOURS - 315 DEGREES AT 01 KTS
POSITION ACCURATE TO WITHIN 045 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.7S 145.8E
---
FORECASTS:
12 HRS, VALID AT:
120600Z --- 13.6S 145.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 335 DEG/ 01 KTS
---
24 HRS, VALID AT:
121800Z --- 13.4S 145.5E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 070 DEG/ 03 KTS
---
36 HRS, VALID AT:
130600Z --- 13.2S 146.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 085 DEG/ 06 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
131800Z --- 13.1S 147.4E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 095 DEG/ 10 KTS
---
72 HRS, VALID AT:
141800Z --- 13.4S 151.5E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 100 DEG/ 13 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
151800Z --- 14.1S 156.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 110 DEG/ 10 KTS
---
120 HRS, VALID AT:
161800Z --- 15.4S 160.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
112100Z POSITION NEAR 13.7S 145.8E.
TROPICAL CYCLONE (TC)18P (NATHAN), LOCATED APPROXIMATELY 192 NM NORTH
OF CAIRNS, AUSTRALIA, HAS TRACKED NORTHWESTWARD AT 01 KNOT OVER
THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A
FLARING CDO FEATURE OBSCURING A CONSOLIDATED LOW LEVEL CIRCULATION
CENTER (LLCC). AN 111811Z SSMIS MICROWAVE IMAGE REVEALS A STRONG
DEEP CONVECTIVE BANDING FEATURE WRAPPING AROUND THE EASTERN
QUADRANTS OF A WELL DEFINED MICROWAVE EYE FEATURE. THE INITIAL
POSITION IS BASED ON THE IR ANIMATION AND THE PGTW FIX WITH GOOD
CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 50 KNOTS BASED ON
AN AVERAGE OF DVORAK INTENSITY ESTIMATES FROM PGTW, KNES, AND ABRF.
UPPER LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE
TO HIGH (20-30 KNOTS) VERTICAL WIND SHEAR (VWS) OFFSET BY STRONG
RADIAL OUTFLOW. TC 18P IS CURRENTLY IN A WEAK STEERING ENVIRONMENT
CAUSING A QUASI-STATIONARY MOTION OVER THE PAST 12 HOURS. THIS
ERRATIC MOTION IS EXPECTED TO PERSIST OVER THE NEXT 24 HOURS UNTIL
THE NEAR EQUATORIAL RIDGE (NER) TO THE NORTHEAST BUILDS IN BECOMING
THE PRIMARY STEERING MECHANISM AND DRIVES THE SYSTEM THE EAST AND
EVENTUALLY SOUTHEAST. TC 18P IS EXPECTED TO CONTINUE TO GRADUALLY
INTENSIFY OVER THE NEXT 72 HOURS DESPITE THE MARGINAL ENVIRONMENT.
HOWEVER, THE SYSTEM WILL EVENTUALLY SUCCUMB TO THE VWS AND BEGIN TO
WEAKEN THEREAFTER AS THE SYSTEM BEGINS ITS SOUTHEASTWARD TRACK NEAR
TAU 96. MODEL GUIDANCE IS IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE
TO THE JTWC FORECAST TRACK WHICH IS LAID CLOSE TO THE MULTI-MODEL
CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 111800Z IS 14 FEET.
NEXT WARNINGS AT 120900Z AND 122100Z. REFER TO TROPICAL CYCLONE 17P
(PAM) WARNINGS (WTPS31 PGTW) FOR SIX-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150312 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 004
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
120600Z --- NEAR 13.3S 145.5E
MOVEMENT PAST SIX HOURS - 045 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.3S 145.5E
---
FORECASTS:
12 HRS, VALID AT:
121800Z --- 13.2S 145.8E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 090 DEG/ 01 KTS
---
24 HRS, VALID AT:
130600Z --- 13.2S 146.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 095 DEG/ 04 KTS
---
36 HRS, VALID AT:
131800Z --- 13.3S 146.9E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 095 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
140600Z --- 13.4S 148.6E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 095 DEG/ 10 KTS
---
72 HRS, VALID AT:
150600Z --- 13.7S 152.7E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 110 DEG/ 16 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
160600Z --- 15.8S 159.0E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 105 DEG/ 22 KTS
---
120 HRS, VALID AT:
170600Z --- 18.2S 167.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
---
REMARKS:
120900Z POSITION NEAR 13.3S 145.6E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 217 NM NORTH
OF CAIRNS, AUSTRALIA, HAS TRACKED NORTHEASTWARD AT 03 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
INDICATES THE SYSTEM HAS SLIGHTLY DEEPENED AS IT REMAINED ALMOST
STATIONARY IN THE CORAL SEA JUST EAST OF CAPE YORK PENINSULA. THE
INITIAL POSITION IS BASED ON A RAGGED LOW REFLECTIVITY CIRCULATION
CENTER IN THE 120551Z 89GHZ GPM MICROWAVE IMAGE WITH FAIR CONFIDENCE.
THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF DVORAK
ESTIMATES FROM REPORTING AGENCIES INCLUDING PGTW, KNES, AND ABRF.
UPPER LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE
TO HIGH (20-30 KNOT) VERTICAL WIND SHEAR (VWS) OFFSET BY STRONG
RADIAL OUTFLOW. TC 18P IS CURRENTLY IN A COL AREA SOUTHWEST OF A NEAR
EQUATORIAL RIDGE (NER) AND NORTHEAST OF A SUBTROPICAL RIDGE. RECENT
STORM MOTION, ALBEIT SLOW, INDICATES THE NER HAS ASSUMED STEERING AND
BEGAN TO NUDGE THE CYCLONE EASTWARD. THE NER IS EXPECTED BUILD AND
BECOME THE DOMINANT STEERING MECHANISM THROUGHOUT THE FORECAST
PERIOD. FAVORABLE UPPER LEVEL CONDITIONS WILL PERSIST, ALLOWING TC
18P TO GRADUALLY INTENSIFY, PEAKING AT 85 KNOTS NEAR TAU 72.
AFTERWARDS, INCREASING VWS AND COOLING SSTS WILL BEGIN TO ERODE THE
SYSTEM. BY TAU 120, THE CYCLONE WILL COMMENCE EXTRA-TROPICAL
TRANSITION. MODEL GUIDANCE IS IN TIGHT AGREEMENT LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST TRACK WHICH IS LAID CLOSE TO THE
MULTI-MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 120600Z IS
18 FEET. NEXT WARNINGS AT 122100Z AND 130900Z. REFER TO TROPICAL
CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW) FOR SIX-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150312 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 005
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
121800Z --- NEAR 13.4S 145.1E
MOVEMENT PAST SIX HOURS - 045 DEGREES AT 01 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.4S 145.1E
---
FORECASTS:
12 HRS, VALID AT:
130600Z --- 13.2S 145.4E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 090 DEG/ 03 KTS
---
24 HRS, VALID AT:
131800Z --- 13.2S 146.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 095 DEG/ 08 KTS
---
36 HRS, VALID AT:
140600Z --- 13.3S 147.7E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 095 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
141800Z --- 13.5S 149.4E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 100 DEG/ 09 KTS
---
72 HRS, VALID AT:
151800Z --- 14.0S 152.9E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 110 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
161800Z --- 15.0S 155.5E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 130 DEG/ 07 KTS
---
120 HRS, VALID AT:
171800Z --- 16.9S 157.8E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL
---
REMARKS:
122100Z POSITION NEAR 13.4S 145.2E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 214 NM NORTH
OF CAIRNS, AUSTRALIA, HAS TRACKED NORTHEASTWARD AT 01 KNOT OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS A QUASI-STATIONARY SYSTEM WITH A FLARING CONVECTIVE
SIGNATURE UNDER MODERATE TO HIGH (20-30 KNOTS) VERTICAL WIND SHEAR
(VWS). THE 121509 GCOM AND THE 121705 SSMI MICROWAVE IMAGES REVEAL A
WELL DEFINED MICROWAVE EYE FEATURE. THE INITIAL POSITION IS BASED ON
THE EIR ANIMATION, PGTW FIX AND AFOREMENTIONED MICROWAVE IMAGES. THE
INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON CONGRUENT DVORAK
CURRENT INTENSITY ESTIMATES FROM PGTW, KNES, AND ABRF. UPPER LEVEL
ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH MODERATE TO HIGH VWS
OFFSET BY STRONG RADIAL OUTFLOW. TC 18P IS CURRENTLY IN A COL AREA
SOUTHWEST OF A NEAR EQUATORIAL RIDGE (NER) AND NORTHEAST OF A
SUBTROPICAL RIDGE. RECENT STORM MOTION, ALBEIT SLOW, INDICATES THE
NER HAS BEGUN TO ASSUME STEERING AND BEGAN TO NUDGE THE CYCLONE
EASTWARD. THE NER IS EXPECTED TO BUILD AND BECOME THE DOMINANT
STEERING MECHANISM THROUGHOUT THE FORECAST PERIOD. VWS IS EXPECTED
TO RELAX TO LOW OR MORE MODERATE CONDITIONS, ALLOWING TC 18P TO
GRADUALLY INTENSIFY, PEAKING AT 85 KNOTS NEAR TAU 72. AFTERWARDS,
INCREASING VWS AND COOLING SSTS WILL BEGIN TO ERODE THE SYSTEM. BY
TAU 120, THE CYCLONE WILL COMMENCE EXTRA-TROPICAL TRANSITION. MODEL
GUIDANCE IS IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC
FORECAST TRACK WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 121800Z IS 18 FEET. NEXT WARNINGS
AT 130900Z AND 132100Z. REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS
(WTPS31 PGTW) FOR SIX-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150313 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 006
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
130600Z --- NEAR 13.1S 145.5E
MOVEMENT PAST SIX HOURS - 065 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.1S 145.5E
---
FORECASTS:
12 HRS, VALID AT:
131800Z --- 12.9S 146.4E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 095 DEG/ 07 KTS
---
24 HRS, VALID AT:
140600Z --- 13.0S 147.8E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 095 DEG/ 09 KTS
---
36 HRS, VALID AT:
141800Z --- 13.1S 149.7E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 095 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
150600Z --- 13.3S 151.7E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 105 DEG/ 07 KTS
---
72 HRS, VALID AT:
160600Z --- 14.1S 154.6E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 120 DEG/ 09 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
170600Z --- 15.9S 157.7E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 130 DEG/ 10 KTS
---
120 HRS, VALID AT:
180600Z --- 18.4S 160.8E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
130900Z POSITION NEAR 13.0S 145.7E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 229 NM
NORTH OF CAIRNS, AUSTRALIA, HAS TRACKED EAST-NORTHEASTWARD AT 02
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION
CENTER WITH THE BULK OF CONVECTION SHEARED TO THE WEST. A 130634Z
SSMIS MICROWAVE IMAGE DEPICTS TIGHT SPIRAL BANDING WRAPPING INTO THE
LOW LEVEL CIRCULATION CENTER WITH WEAKENED CURVED CONVECTIVE BANDING
WRAPPING AROUND THE WESTERN PERIPHERY. UPPER LEVEL ANALYSIS
INDICATES AN AREA OF MODERATE TO HIGH (20-30 KNOT) EASTERLY VERTICAL
WIND SHEAR (VWS) WHICH IS OFFSET BY EXCELLENT POLEWARD OUTFLOW AS
EVIDENT IN THE WATER VAPOR LOOP. THE INITIAL POSITION IS BASED ON
THE MSI ANIMATION AND THE SSMIS IMAGE WITH GOOD CONFIDENCE. THE
INITIAL INTENSITY REMAINS AT 55 KNOTS BASED ON CONSENSUS CURRENT
INTENSITY ESTIMATES FROM PGTW, KNES, AND ABRF. TC 18P IS SLOWLY
TRACKING WESTWARD AS A NEAR EQUATORIAL RIDGE (NER) BUILDS IN FROM
THE NORTH. THIS NER WILL TAKE OVER AS THE DOMINANT STEERING
MECHANISM THROUGHOUT THE FORECAST PERIOD. AS TC NATHAN TRACKS
EASTWARD, VWS WILL DECREASE AND SEA SURFACE TEMPERATURES WILL REMAIN
ABOVE 30C, ALLOWING TC 18P TO INTENSIFY TO A PEAK OF 85 KNOTS NEAR
TAU 48. BEYOND TAU 72, VWS WILL INCREASE BEGINNING A WEAKENING TREND
AS IT TRACKS POLEWARD TOWARDS THE STRONG WESTERLIES ASSOCIATED WITH
THE BAROCLINIC ZONE. MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT,
LENDING HIGH CONFIDENCE TO THE JTWC OFFICIAL TRACK. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 130600Z IS 18 FEET. NEXT WARNINGS AT
132100Z AND 140900Z. REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS
(WTPS31 PGTW) FOR SIX-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150313 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 007//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 007
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
131800Z --- NEAR 13.1S 145.3E
MOVEMENT PAST SIX HOURS - 090 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.1S 145.3E
---
FORECASTS:
12 HRS, VALID AT:
140600Z --- 12.9S 146.3E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 090 DEG/ 07 KTS
---
24 HRS, VALID AT:
141800Z --- 12.9S 147.8E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 100 DEG/ 07 KTS
---
36 HRS, VALID AT:
150600Z --- 13.1S 149.2E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 110 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
151800Z --- 13.5S 150.5E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 120 DEG/ 04 KTS
---
72 HRS, VALID AT:
161800Z --- 14.4S 152.1E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 120 DEG/ 03 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
171800Z --- 15.1S 153.3E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 125 DEG/ 04 KTS
---
120 HRS, VALID AT:
181800Z --- 16.0S 154.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
132100Z POSITION NEAR 13.0S 145.6E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 230 NM NORTH
OF CAIRNS, AUSTRALIA, HAS TRACKED EASTWARD AT 02 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
DEPICTS FLARING DEEP CONVECTION ASSOCIATED WITH A CONSOLIDATED LOW
LEVEL CIRCULATION CENTER (LLCC). THE 131649Z 37GHZ SSMI MICROWAVE
IMAGE REVEALS THE MICROWAVE EYE FEATURE HAS FINALLY STARTED TO MOVE
SLIGHTLY EAST. THE INITIAL POSITION IS BASED ON THE EIR ANIMATION AS
WELL AS EXTRAPOLATED FROM THE AFOREMENTIONED MICROWAVE IMAGE. THE
INITIAL INTENSITY REMAINS AT 55 KNOTS BASED ON CONGRUENT DVORAK
CURRENT INTENSITY ESTIMATES FROM PGTW AND ABRF. UPPER ANALYSIS
INDICATES AN IMPROVED ENVIRONMENT AS THE VERTICAL WIND SHEAR (VWS)
HAS RELAXED TO MORE FAVORABLE LEVELS (10-20 KNOTS) AND OUTFLOW
CHANNELS HAVE IMPROVED BOTH POLEWARD AND EQUATORWARD. TC 18P REMAINS
IN AN AREA OF COMPETING STEERING MECHANISMS. HOWEVER, THE NEAR
EQUATORIAL RIDGE (NER) TO THE NORTHEAST APPEARS TO HAVE GAINED
CONTROL AS THE SYSTEM IS SLOWLY MAKING ITS WAY EAST. THIS EASTWARD
TRACK DIRECTION IS EXPECTED OVER THE NEXT 48 HOURS AS THE SYSTEM
INTENSIFIES TO A PEAK OF 95 KNOTS. THE SYSTEM WILL THEN BEGIN TO
MOVE SLIGHTLY POLEWARD, SLOW, AND WEAKEN AS RIDGING BUILDS INTO THE
SOUTHWEST. THIS RIDGING HAS THE POTENTIAL TO NOT ONLY SLOW THE
PROGRESS OF TC 18P, BUT MAY ACTUALLY CAUSE THE CYCLONE TO BECOME
QUASI-STATIONARY OR EVEN RETROGRADE BACK TO THE WEST. COLD AIR
ADVECTION ASSOCIATED WITH THE HIGH PRESSURE IS ALSO EXPECTED WHICH
WILL LEAD TO A WEAKENING OF THE SYSTEM IN THE LATER TAUS. THE JTWC
FORECAST TRACK HAS SIGNIFICANTLY SLOWED FROM PREVIOUS FORECASTS DUE
TO THE NEWLY ANTICIPATED DYNAMICS. OVERALL, DYNAMIC GUIDANCE IS IN
CLOSE AGREEMENT, WITH THE EXCEPTION OF GFDN, LENDING HIGH CONFIDENCE
TO THE JTWC FORECAST TRACK WHICH IS LAID CLOSE, BUT SLIGHTLY SLOWER
THAN THE MULTI-MODEL CONSENSUS. THROUGH TAU 120 MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 131800Z IS 18 FEET. NEXT WARNINGS AT 140900Z AND
142100Z. REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW)
FOR SIX-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150314 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 008//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 008
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
140600Z --- NEAR 13.1S 146.1E
MOVEMENT PAST SIX HOURS - 090 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.1S 146.1E
---
FORECASTS:
12 HRS, VALID AT:
141800Z --- 12.9S 147.3E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 090 DEG/ 06 KTS
---
24 HRS, VALID AT:
150600Z --- 12.9S 148.5E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 105 DEG/ 04 KTS
---
36 HRS, VALID AT:
151800Z --- 13.1S 149.4E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 130 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
160600Z --- 13.5S 149.9E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 125 DEG/ 02 KTS
---
72 HRS, VALID AT:
170600Z --- 14.0S 150.7E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
095 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 140 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
180600Z --- 15.6S 152.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 225 DEG/ 03 KTS
---
120 HRS, VALID AT:
190600Z --- 16.4S 151.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
140900Z POSITION NEAR 13.0S 146.4E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 229 NM
NORTH OF CAIRNS, AUSTRALIA, HAS TRACKED EASTWARD AT 05 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A NEARLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
ASSOCIATED LIGHT FLARING CONVECTION. THE 140547Z 37GHZ SSMIS
MICROWAVE IMAGE REVEALS A CONSOLIDATED LLCC WITH DEEP BANDING
WRAPPING FROM THE SOUTH. THE INITIAL POSITION IS BASED ON THE MSI
ANIMATION AS WELL AS EXTRAPOLATED FROM THE AFOREMENTIONED MICROWAVE
IMAGE. THE INITIAL INTENSITY HAS DECREASED TO 45 KNOTS BASED ON 3.0
DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW AND ABRF. UPPER LEVEL
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH VERTICAL WIND SHEAR
(VWS) AT (5-10 KNOTS) AND OUTFLOW CHANNELS BOTH POLEWARD AND
EQUATORWARD. TC 18P REMAINS IN AN AREA OF COMPETING STEERING
MECHANISMS. HOWEVER, THE NEAR EQUATORIAL RIDGE (NER) TO THE
NORTHEAST APPEARS TO HAVE GAINED CONTROL AS THE SYSTEM IS SLOWLY
TRACKING TO THE EAST. AS THE SYSTEM MOVES TO THE EAST, EXPECT
INTENSIFICATION DUE TO POSITIVE UPPER-LEVEL OUTFLOW AND GOOD OCEAN
HEAT CONTENT. THIS WILL REMAIN BEYOND TAU 36 AS A NER WILL BUILD TO
THE NORTHWEST OF THE SYSTEM, CAUSING TC NATHAN TO TRACK TO THE
SOUTHEAST. IN THE EXTENDED FORECAST, TC 18P WILL BECOME QUASI-
STATIONARY AND BEGIN TO WEAKEN AS COLD AIR ADVECTION ASSOCIATED WITH
THE HIGH PRESSURE OVER CENTRAL AUSTRALIA WILL LEAD TO A WEAKENING OF
THE SYSTEM. THE COMPETING STEERING ENVIRONMENT BETWEEN THE NER TO
THE NORTHWEST AND THE SUBTROPICAL RIDGE IN OVER THE NORTHERN
TERRITORY WILL CAUSE TC NATHAN TO TURN BACK WESTWARD AS IT WEAKENS.
THERE IS SIGNIFICANT DISPARITY IN THE TIMING OF THE TURN POLEWARD IN
THE DYNAMIC MODEL GUIDANCE, WHICH LEADS TO AN OVERALL LOW CONFIDENCE
IN THE JTWC FORECAST TRACK BEYOND TAU 36. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 140600Z IS 20 FEET. NEXT WARNINGS AT 142100Z AND 150900Z.
REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW)FOR TWELVE-
HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150314 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 009//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 009
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
141800Z --- NEAR 13.3S 147.7E
MOVEMENT PAST SIX HOURS - 095 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.3S 147.7E
---
FORECASTS:
12 HRS, VALID AT:
150600Z --- 13.3S 148.8E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 100 DEG/ 05 KTS
---
24 HRS, VALID AT:
151800Z --- 13.5S 149.8E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 120 DEG/ 04 KTS
---
36 HRS, VALID AT:
160600Z --- 13.9S 150.5E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 135 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
161800Z --- 14.4S 151.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 03 KTS
---
72 HRS, VALID AT:
171800Z --- 15.3S 151.8E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 170 DEG/ 02 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
181800Z --- 15.9S 151.9E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 250 DEG/ 02 KTS
---
120 HRS, VALID AT:
191800Z --- 16.1S 151.3E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
142100Z POSITION NEAR 13.3S 148.0E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 242 NM
NORTH-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED EASTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
INDICATES A SLIGHTLY IMPROVED CONVECTIVE STRUCTURE WITH RENEWED DEEP
CONVECTIVE BANDING. A 141908Z MHS NOAA-18 IMAGE INDICATES BROAD
CURVED CONVECTIVE BANDING OVER THE NORTHERN SEMI-CIRCLE WRAPPING
INTO THE SOUTHEAST QUADRANT OF THE LOW-LEVEL CIRCULATION CENTER.
DESPITE THE IMPROVEMENT IN ORGANIZATION, THE INITIAL INTENSITY IS
ASSESSED AT 40 KNOTS BASED ON RECENT ASCAT IMAGERY INDICATING 35 TO
40 KNOT WINDS AND DVORAK CURRENT INTENSITY ESTIMATES OF 35 KNOTS. TC
18P IS TRACKING EASTWARD ALONG THE SOUTHERN PERIPHERY OF THE NEAR-
EQUATORIAL RIDGE AND IS FORECAST TO CONTINUE TRACKING EASTWARD TO
SOUTHEASTWARD THROUGH TAU 48. AFTER TAU 48, THE SYSTEM WILL THEN
BEGIN TO MOVE SLIGHTLY POLEWARD, SLOW, AND WEAKEN AS RIDGING BUILDS
INTO THE SOUTH. THIS RIDGING HAS THE POTENTIAL TO NOT ONLY SLOW THE
PROGRESS OF TC 18P, BUT MAY ACTUALLY CAUSE THE CYCLONE TO BECOME
QUASI-STATIONARY OR EVEN RETROGRADE BACK TO THE WEST. COLD AIR
ADVECTION ASSOCIATED WITH THE HIGH PRESSURE IS ALSO EXPECTED WHICH
WILL LEAD TO A WEAKENING OF THE SYSTEM IN THE LATER TAUS. OVERALL,
DYNAMIC GUIDANCE IS IN POOR AGREEMENT, THEREFORE THERE IS LOW
CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 141800Z IS 20 FEET. NEXT WARNINGS AT 150900Z AND 152100Z.
REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW) FOR
TWELVE-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150315 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 010//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 010
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
150600Z --- NEAR 13.5S 149.0E
MOVEMENT PAST SIX HOURS - 100 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.5S 149.0E
---
FORECASTS:
12 HRS, VALID AT:
151800Z --- 13.8S 149.7E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 135 DEG/ 03 KTS
---
24 HRS, VALID AT:
160600Z --- 14.3S 150.2E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 155 DEG/ 03 KTS
---
36 HRS, VALID AT:
161800Z --- 14.9S 150.5E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 160 DEG/ 04 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
170600Z --- 15.6S 150.8E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 170 DEG/ 03 KTS
---
72 HRS, VALID AT:
180600Z --- 16.6S 151.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 210 DEG/ 01 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
190600Z --- 17.1S 150.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 120 HR POSIT: 285 DEG/ 02 KTS
---
120 HRS, VALID AT:
200600Z --- 16.9S 149.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
150900Z POSITION NEAR 13.6S 149.2E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 276 NM
NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED EASTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
INDICATES A SLIGHTLY IMPROVING CONVECTIVE STRUCTURE WITH SOME DEEP
CONVECTIVE BANDING. A 150236Z GCOM ALSO SHOWS SOME BANDING, HOWEVER
THE SYSTEM STILL APPEARS FAIRLY WEAK IN THE WATER VAPOR LOOP. A
150428Z ISS RSCAT SHOWS THAT THE STRONGEST WINDS (STILL ASSESSED AT
40KTS) REMAIN IN THE NORTHERN PERIPHERY OF THE SYSTEM, WITH
SIGNIFICANTLY WEAKER WINDS IN THE SOUTHERN PORTION. UPPER LEVEL
ANALYSIS INDICATES THAT MODERATE TO HIGH (20 TO 30 KNOTS) VERTICAL
WIND SHEAR IS OFFSET BY GOOD DUAL OUTFLOW CHANNEL S. TC NATHAN IS
TRACKING SOUTHEASTWARD ALONG THE SOUTHEASTERN PERIPHERY OF THE NEAR-
EQUATORIAL RIDGE BUILDING TO THE NORTHWEST AND IS FORECAST TO
CONTINUE TRACKING SOUTHEASTWARD THROUGH TAU 48. AFTER TAU 48, THE
SYSTEM WILL THEN BEGIN TO MOVE SLIGHTLY POLEWARD, DROP IN SPEED AND
WEAKEN AS A RIDGE BUILDS IN SOUTHWEST OF THE SYSTEM, FORCING COOLER
DRY AIR INTO TC NATHAN. THIS RIDGING HAS THE POTENTIAL TO NOT ONLY
SLOW THE SYSTEM BUT MAY ACTUALLY CAUSE THE CYCLONE TO BECOME QUASI-
STATIONARY OR EVEN TRACK BACK TO THE WEST. HOWEVER, OVERALL
DYNAMIC GUIDANCE IS IN POOR AGREEMENT WITH THE TIMING AND TRACK OF
THE SYSTEM SLOW DOWN AND RETROGRADE TO THE WEST AND AS SUCH THERE IS
LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 150600Z IS 22 FEET. NEXT WARNINGS AT 152100Z AND 160900Z.
REFER TO TROPICAL CYCLONE 17P (PAM) WARNINGS (WTPS31 PGTW)
FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150315 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 011//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 011
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
151800Z --- NEAR 13.7S 149.8E
MOVEMENT PAST SIX HOURS - 110 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.7S 149.8E
---
FORECASTS:
12 HRS, VALID AT:
160600Z --- 14.2S 150.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 150 DEG/ 03 KTS
---
24 HRS, VALID AT:
161800Z --- 14.7S 150.7E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 160 DEG/ 03 KTS
---
36 HRS, VALID AT:
170600Z --- 15.3S 150.9E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 170 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
171800Z --- 15.9S 151.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 190 DEG/ 02 KTS
---
72 HRS, VALID AT:
181800Z --- 16.5S 150.9E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 260 DEG/ 03 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
191800Z --- 16.7S 149.5E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 275 DEG/ 04 KTS
---
120 HRS, VALID AT:
201800Z --- 16.6S 147.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
152100Z POSITION NEAR 13.8S 149.9E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 301 NM
NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED EAST-SOUTHEASTWARD AT
03 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A SLOWLY-CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH FRAGMENTED DEEP CONVECTIVE BANDING
OVER THE NORTHERN SEMI-CIRCLE WITH AN AREA OF PERSISTENT, ASYMMETRIC
CONVECTION OVER THE CENTER. A 151618Z SSMI IMAGE SHOWS A PARTIALLY-
EXPOSED LLCC WITH SHALLOW BANDING WRAPPING TIGHTLY INTO THE DEFINED
CENTER, WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. A
151115Z ASCAT IMAGE PROVIDES EVIDENCE THAT THE SURFACE WIND FIELD IS
WEAKER THAN SATELLITE IMAGERY SUGGESTS WITH 40 TO 45 KNOT WINDS.
ADDITIONALLY, THE SYSTEM REMAINS UNDER MODERATE EASTERLY VERTICAL
WIND SHEAR (VWS) WITH WEAK POLEWARD OUTFLOW. THE INITIAL INTENSITY
IS ASSESSED AT 45 KNOTS, SLIGHTLY HIGHER THAN THE PREVIOUS WARNING,
AND IS BASED PRIMARILY ON THE ASCAT DATA, WHICH FALLS WITHIN A WIDE
RANGE OF DVORAK INTENSITY ESTIMATES OF 35 TO 55 KNOTS. TC 18P IS
TRACKING SLOWLY ALONG THE SOUTHERN PERIPHERY OF THE NEAR-EQUATORIAL
RIDGE BUT IS FORECAST TO TURN SOUTHWARD ALONG THE WESTERN PERIPHERY
OF THE STEERING RIDGE BY TAU 12. THIS SOUTHWARD MOTION SHOULD
CONTINUE THROUGH TAU 72 UNTIL THE SUBTROPICAL RIDGE (STR) BUILDS IN
TO THE SOUTH PRODUCING A WESTWARD TRACK MOTION TOWARD NORTHEAST
AUSTRALIA. ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY CONDUCIVE FOR
FURTHER DEVELOPMENT WITH NO EVIDENCE OF DRY AIR ON THE RECENT WILLIS
ISLAND SOUNDING AND TOTAL PRECIPITABLE WATER PRODUCT, THEREFORE, TC
18P SHOULD SLOWLY INTENSIFY TO A PEAK INTENSITY OF 70 KNOTS BY TAU
36 TO 48. HOWEVER, AFTER TAU 48, AS THE STR BUILDS, THE DYNAMIC
MODELS INDICATE AN INFLUX OF DRIER, COOLER, MORE STABLE AIR, WHICH
SHOULD SERVE TO WEAKEN THE SYSTEM SIGNIFICANTLY. DUE TO THE COMPLEX
STEERING ENVIRONMENT, DYNAMIC GUIDANCE REMAINS IN POOR AGREEMENT,
THEREFORE THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 151800Z IS 22 FEET. NEXT
WARNINGS AT 160900Z AND 162100Z. REFER TO TROPICAL CYCLONE 17P (PAM)
FINAL WARNING (WTPS31 PGTW).//
=========================================================================
WTPS32 PGTW 20150316 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 012//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 012
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
160600Z --- NEAR 14.3S 150.2E
MOVEMENT PAST SIX HOURS - 145 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.3S 150.2E
---
FORECASTS:
12 HRS, VALID AT:
161800Z --- 14.7S 150.3E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 170 DEG/ 04 KTS
---
24 HRS, VALID AT:
170600Z --- 15.4S 150.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 170 DEG/ 03 KTS
---
36 HRS, VALID AT:
171800Z --- 16.0S 150.5E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 200 DEG/ 02 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
180600Z --- 16.3S 150.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 245 DEG/ 03 KTS
---
72 HRS, VALID AT:
190600Z --- 16.7S 149.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 270 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
200600Z --- 16.7S 146.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 280 DEG/ 07 KTS
---
120 HRS, VALID AT:
210600Z --- 16.3S 144.2E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
160900Z POSITION NEAR 14.4S 150.2E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 298 NM
EAST-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 05
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A SLOWLY-CONSOLIDATING LOW-LEVEL CIRCULATION CENTER
(LLCC) SLIGHTLY TO THE EAST OF THE DEEPENING CONVECTION. A 160452Z
SSMI IMAGE SHOWS A PARTIALLY-EXPOSED LLCC WITH SOME SHALLOW BANDING
WRAPPING TIGHTLY INTO THE DEFINED CENTER, WHICH SUPPORTS THE INITIAL
POSITION WITH FAIR CONFIDENCE AND THE MODERATE VERTICAL WIND SHEAR
(VWS). UPPER LEVEL ANALYSIS CONFIRMS 20 KNOTS OF EASTERLY VWS AND
AVERAGE RADIAL OUTFLOW. TC 18P IS TRACKING SLOWLY ALONG THE WESTERN
PERIPHERY OF A BUILDING SUBTROPICAL RIDGE (STR). THIS SOUTHWARD
MOTION SHOULD CONTINUE THROUGH TAU 48 UNTIL ANOTHER STR BUILDS IN
TO THE SOUTHWEST, PRODUCING A WESTWARD TRACK MOTION TOWARD NORTHEAST
AUSTRALIA. ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY CONDUCIVE FOR
SOME DEVELOPMENT, SLOWLY INTENSIFYING TO A PEAK OF 70 KNOTS BY TAU
48. HOWEVER, AFTER BEYOND TAU 48, AS THE STR BUILDS, THE DYNAMIC
MODELS INDICATE AN INFLUX OF DRIER, COOLER, MORE STABLE AIR, WHICH
SHOULD SERVE TO WEAKEN THE SYSTEM SIGNIFICANTLY. DUE TO THE COMPLEX
STEERING ENVIRONMENT, DYNAMIC GUIDANCE REMAINS IN POOR AGREEMENT,
THEREFORE THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 160600Z IS 24 FEET. NEXT WARNINGS
AT 162100Z AND 170900Z.//
=========================================================================
WTPS32 PGTW 20150316 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 013//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 013
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
161800Z --- NEAR 14.2S 149.6E
MOVEMENT PAST SIX HOURS - 295 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.2S 149.6E
---
FORECASTS:
12 HRS, VALID AT:
170600Z --- 14.4S 149.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 180 DEG/ 03 KTS
---
24 HRS, VALID AT:
171800Z --- 14.9S 149.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 200 DEG/ 03 KTS
---
36 HRS, VALID AT:
180600Z --- 15.5S 149.2E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 240 DEG/ 04 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
181800Z --- 15.9S 148.5E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 260 DEG/ 06 KTS
---
72 HRS, VALID AT:
191800Z --- 16.2S 146.2E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 270 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
201800Z --- 16.2S 143.6E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
162100Z POSITION NEAR 14.2S 149.5E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 273 NM
NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED WEST-NORTHWESTWARD AT
02 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS FLARING CENTRAL CONVECTION SLIGHTLY
DISPLACED TO THE WEST OF A LOW-LEVEL CIRCULATION CENTER. THE CURRENT
POSITION IS BASED ON THE EIR ANIMATION AND SATELLITE FIXES FROM PGTW
AND KNES. THE INITIAL INTENSITY OF 40 KNOTS IS HEDGED HIGHER THAN
DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 FROM PGTW AND KNES. UPPER-
LEVEL ANALYSIS INDICATES TC 18P IS LOCATED IN A LOW TO MODERATE (10
TO 20 KNOT) VERTICAL WIND SHEAR AND GOOD OUTFLOW. SLOW AND/OR
POSSIBLE QUASI-STATIONARY MOVEMENT IS EXPECTED OVER THE NEXT 36
HOURS AS TC 18P IS UNDER THE INFLUENCE OF A COMPETING STEERING
ENVIRONMENT BETWEEN TWO SUBTROPICAL RIDGES (STR): ONE TO THE
NORTHEAST AND ONE TO THE SOUTHWEST. AFTER TAU 36, THE STR THAT IS
LOCATED SOUTHWESTWARD OF THE SYSTEM IS EXPECTED TO BUILD AND EXTEND
EASTWARD, DOMINATING THE STEERING PATTERN AND TAKING TC NATHAN ON A
WESTWARD TRACK. UPPER-LEVEL CONDITIONS ARE EXPECTED TO IMPROVE,
ALLOWING TC 18P TO STEADILY INTENSIFY LEADING TO A PEAK INTENSITY OF
75 KNOTS BY TAU 48. AFTERWARDS, TC NATHAN IS EXPECTED TO SLOWLY
WEAKEN AS IT APPROACHES THE NORTHEASTERN COAST OF AUSTRALIA AND
FURTHER DISSIPATES OVERLAND BY THE END OF THE FORECAST PERIOD. WINDS
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 161800Z IS 22 FEET. NEXT WARNINGS
AT 170900Z AND 172100Z.//
=========================================================================
WTPS32 PGTW 20150317 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 014//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 014
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
170600Z --- NEAR 14.6S 149.5E
MOVEMENT PAST SIX HOURS - 205 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 045 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.6S 149.5E
---
FORECASTS:
12 HRS, VALID AT:
171800Z --- 14.8S 149.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
090 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 225 DEG/ 02 KTS
---
24 HRS, VALID AT:
180600Z --- 15.1S 149.1E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 250 DEG/ 03 KTS
---
36 HRS, VALID AT:
181800Z --- 15.3S 148.5E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 260 DEG/ 06 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
190600Z --- 15.5S 147.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 270 DEG/ 08 KTS
---
72 HRS, VALID AT:
200600Z --- 15.4S 144.0E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 96 HR POSIT: 285 DEG/ 08 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
210600Z --- 14.6S 140.8E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
170900Z POSITION NEAR 14.6S 149.5E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 254 NM EAST-
NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD
AT 02 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED
ON RECENT MICROWAVE SATELLITE IMAGERY, INCLUDING A 170437Z SSMIS
PASS. THE INTENSITY OF 45 KNOTS IS CONSISTENT WITH EARLIER ASCAT
DATA AND AUTOMATED SATELLITE INTENSITY ESTIMATES FROM CIMSS. THE LOW-
LEVEL CIRCULATION CENTER OF TC 18P REMAINS PARTIALLY EXPOSED DUE TO
PERSISTENT NORTHEASTERLY VERTICAL WIND SHEAR. OVER THE NEXT 36
HOURS, A SUBTROPICAL RIDGE IS EXPECTED TO BUILD TO THE SOUTHWEST AND
STEER THE CYCLONE OUT OF THE CURRENT WEAK STEERING ENVIRONMENT
TOWARD A WESTWARD TRACK. NEAR-TERM INTENSITY CHANGE WILL BE LIMITED
BY PERSISTENT VERTICAL WIND SHEAR. HOWEVER, SHEAR IS EXPECTED TO
DROP AFTER TAU 24 AS THE UPPER-LEVEL PATTERN REORIENTS, WHICH SHOULD
ALLOW TC 18P TO INTENSIFY STEADILY PRIOR TO LANDFALL. THE CURRENT
FORECAST CALLS FOR TC 18P TO CROSS THE CAPE YORK PENINSULA AND
DISSIPATE DUE TO LAND INTERACTION BY TAU 96. HOWEVER, THE REMNANT
CIRCULATION MAY REMAIN NEAR THE WARNING INTENSITY THRESHOLD OF 35
KNOTS AND POTENTIALLY REGENERATE AFTER EMERGING OVER THE GULF OF
CARPENTARIA. NUMERICAL MODEL GUIDANCE HAS SHIFTED A BIT EQUATORWARD
OVER THE PAST 12 HOURS, AS HAS THE TRACK FORECAST. THERE IS GOOD
AGREEMENT REGARDING THE GENERAL TRACK DIRECTION AMONG FORECAST
MODELS, ALTHOUGH THERE IS STILL SOME UNCERTAINTY REGARDING THE
PRECISE LANDFALL LOCATION AND TIMING. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 170600Z IS 22 FEET. NEXT WARNINGS AT 172100Z AND 180900Z.//
=========================================================================
WTPS32 PGTW 20150317 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 015//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 015
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
171800Z --- NEAR 14.9S 149.4E
MOVEMENT PAST SIX HOURS - 225 DEGREES AT 01 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.9S 149.4E
---
FORECASTS:
12 HRS, VALID AT:
180600Z --- 15.1S 149.1E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 260 DEG/ 03 KTS
---
24 HRS, VALID AT:
181800Z --- 15.2S 148.5E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
110 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 265 DEG/ 06 KTS
---
36 HRS, VALID AT:
190600Z --- 15.3S 147.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
115 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 270 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
191800Z --- 15.3S 145.7E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 275 DEG/ 07 KTS
---
72 HRS, VALID AT:
201800Z --- 15.0S 142.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 96 HR POSIT: 290 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
211800Z --- 14.1S 140.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
172100Z POSITION NEAR 15.0S 149.3E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 240 NM
EAST-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 01
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY AND 171833Z SSMIS MICROWAVE IMAGE DEPICT DEEPENED
CENTRAL CONVECTION OBSCURING A LOW-LEVEL CIRCULATION CENTER. THE
CURRENT POSITION IS BASED ON THE EIR ANIMATION AND SATELLITE FIXES
FROM PGTW, KNES AND ABRF WITH FAIR CONFIDENCE. THE INITIAL INTENSITY
REMAINS AT 45 KNOTS BASED ON AN OVERALL ASSESSMENT OF DVORAK
INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES. UPPER-LEVEL
ANALYSIS INDICATES TC 18P IS LOCATED IN AN AREA OF LOW (05 TO 10
KNOT) VERTICAL WIND SHEAR AND GOOD POLEWARD OUTFLOW. ADDITIONALLY,
SEA SURFACE TEMPERATURES IN THE AREA ARE CONDUCIVE FOR DEVELOPMENT.
TC 18P IS CURRENTLY TRACKING SLOWLY UNDER THE INFLUENCE OF A WEAK
STEERING ENVIRONMENT. SLOW MOVEMENT IS EXPECTED OVER THE NEXT 12
HOURS AS THE SUBTROPICAL RIDGE TO THE SOUTHWEST BUILDS AND EXTENDS
EASTWARD, DOMINATING THE STEERING PATTERN AND TAKING TC NATHAN ON A
WESTWARD TRACK. UPPER-LEVEL CONDITIONS ARE EXPECTED TO IMPROVE,
ALLOWING TC 18P TO STEADILY INTENSIFY LEADING TO A PEAK INTENSITY OF
75 KNOTS BY TAU 36. TC NATHAN IS FORECAST TO MAKE LANDFALL AFTER TAU
48 AND DISSIPATE AS IT DRIFTS ACROSS THE CAPE YORK PENINSULA. THE
REMNANT CIRCULATION IS FORECAST TO POTENTIALLY REGENERATE AFTER
EMERGING OVER THE GULF OF CARPENTARIA. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 171800Z IS 22 FEET. NEXT WARNINGS AT 180900Z AND 182100Z.//
=========================================================================
WTPS32 PGTW 20150318 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 016//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 016
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
180600Z --- NEAR 14.9S 149.1E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 02 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
090 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.9S 149.1E
---
FORECASTS:
12 HRS, VALID AT:
181800Z --- 15.0S 148.4E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
095 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 275 DEG/ 07 KTS
---
24 HRS, VALID AT:
190600Z --- 14.9S 147.0E
MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 270 DEG/ 11 KTS
---
36 HRS, VALID AT:
191800Z --- 14.9S 144.8E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 275 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
200600Z --- 14.8S 142.8E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 285 DEG/ 09 KTS
---
72 HRS, VALID AT:
210600Z --- 13.9S 139.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 290 DEG/ 08 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
220600Z --- 12.8S 136.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 280 DEG/ 06 KTS
---
120 HRS, VALID AT:
230600Z --- 12.4S 133.4E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
180900Z POSITION NEAR 14.9S 148.9E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 225 NM EAST-
NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED WESTWARD AT 02 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS THE SYSTEM HAS DEVELOPED A 5-NM PINHOLE EYE AS IT CONTINUED TO
CONSOLIDATE AND DEEPEN. THE INITIAL POSITION IS BASED ON THE ABOVE
EYE FEATURE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON
AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES, AND ABRF.
UPPER-LEVEL ANALYSIS INDICATES TC 18P IS LOCATED IN AN AREA OF LOW
(05 TO 10 KNOT) VERTICAL WIND SHEAR AND GOOD RADIAL OUTFLOW AS A
POINT-SOURCE ANTICYCLONE DEVELOPED OVERHEAD. ADDITIONALLY, SEA
SURFACE TEMPERATURES IN THE AREA ARE CONDUCIVE FOR DEVELOPMENT. TC
18P IS TRACKING SLOWLY WESTWARD AS THE SUBTROPICAL RIDGE (STR) TO THE
SOUTHWEST BUILDS. THE STR WILL EVENTUALLY DOMINATE THE STEERING
PATTERN AND DRIVE TC NATHAN ON A SOLID WESTWARD TRACK. UPPER-LEVEL
CONDITIONS ARE ALSO EXPECTED TO IMPROVE, ALLOWING TC 18P TO STEADILY
INTENSIFY LEADING TO A PEAK OF 85 KNOTS BY TAU 24 BEFORE MAKING
LANDFALL AND CROSSING CAPE YORK PENINSULA. FRICTIONAL EFFECTS WILL
CAUSE DEGRADATION BUT NATHAN WILL EMERGE IN THE GULF OF CARPENTARIA
AS A 50-KNOT SYSTEM, RE-INTENSIFY SLIGHTLY BEFORE MAKING A SECONDARY
LANDFALL OVER CAPE ARNHEM BEFORE TAU 96. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 180600Z IS 25 FEET. NEXT WARNINGS AT 182100Z AND 190900Z.//
=========================================================================
WTPS32 PGTW 20150318 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 017//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 017
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
181800Z --- NEAR 14.7S 148.2E
MOVEMENT PAST SIX HOURS - 280 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT
105 NM SOUTHEAST QUADRANT
110 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.7S 148.2E
---
FORECASTS:
12 HRS, VALID AT:
190600Z --- 14.6S 146.8E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
105 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 275 DEG/ 08 KTS
---
24 HRS, VALID AT:
191800Z --- 14.5S 145.1E
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
110 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 275 DEG/ 10 KTS
---
36 HRS, VALID AT:
200600Z --- 14.3S 143.1E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 275 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
201800Z --- 14.1S 141.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 290 DEG/ 08 KTS
---
72 HRS, VALID AT:
211800Z --- 13.0S 137.9E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 290 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
221800Z --- 12.0S 135.1E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 275 DEG/ 07 KTS
---
120 HRS, VALID AT:
231800Z --- 11.8S 132.2E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
182100Z POSITION NEAR 14.7S 147.9E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 191 NM
NORTHEAST OF CAIRNS, AUSTRALIA HAS TRACKED WESTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A MORE CONSOLIDATED STRUCTURE WITH DEEP CONVECTIVE
BANDING WRAPPING INTO THE CLOUD SYSTEM CENTER, DESPITE THE PINHOLE
EYE BECOMING CLOUD FILLED. FURTHERMORE, THE BD CURVE ENHANCEMENT
DEPICTS COOLING CLOUD TOPS WITHIN THE EXPANDING CENTRAL CORE,
INDICATING CONTINUED INTENSIFICATION. AN 181820Z SSMIS MICROWAVE
IMAGE CONFIRMS THE INCREASED CONVECTION WITHIN THE CORE AND MORE
INTENSE CONVECTIVE BANDING ALONG THE NORTHERN PERIPHERY WRAPPING
AROUND THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS
BASED ON THE AFOREMENTIONED SSMIS IMAGE AND SUPPORTED BY AGENCY
FIXES AS WELL AS THE WILLIS ISLAND RADAR LOOP WITH GOOD CONFIDENCE.
THE INITIAL INTENSITY IS BASED ON AN AVERAGE OF DVORAK INTENSITY
ESTIMATES FROM PGTW, ABRF, AND KNES. UPPER LEVEL ANALYSIS INDICATES
A VERY FAVORABLE ENVIRONMENT WITH A POINT SOURCE ABOVE TC 18P
PROVIDING RADIAL OUTFLOW AND LOW (5-10 KNOT) VERTICAL WIND SHEAR
(VWS). IN ADDITION, SEA SURFACE TEMPERATURES (SSTS) OF 28C WILL
CONTINUE TO FUEL FURTHER DEVELOPMENT. TC NATHAN IS TRACKING ALONG
THE NORTHERN PERIPHERY OF A BUILDING DEEP LAYER SUB-TROPICAL RIDGE
(STR) OVER CENTRAL AUSTRALIA. THIS STR WILL CONTINUE TO SERVE AS THE
STEERING MECHANISM THROUGHOUT THE FORECAST PERIOD, SUPPORTING A WEST
TO WEST-NORTHWESTWARD TRACK. FAVORABLE ENVIRONMENTAL CONDITIONS WILL
PERSIST, ALLOWING TC 18P TO FURTHER INTENSIFY PRIOR TO MAKING
LANDFALL OVER THE CAPE YORK PENINSULA WITHIN 24 HOURS. TC NATHAN
WILL WEAKEN AS IT TRACKS ALONG THE CAPE YORK PENINSULA DUE TO LAND
INTERACTION. CONTINUED FAVORABLE UPPER LEVEL CONDITIONS AND SSTS
ABOVE 30C IN THE GULF OF CARPENTARIA WILL ALLOW TC NATHAN TO RE-
INTENSIFY WHEN IT EMERGES BACK OVER WATER. THE SYSTEM IS FORECAST TO
MAKE A SECONDARY LANDFALL OVER CAPE ARNHEM AND WEAKEN ONCE AGAIN DUE
TO LAND INTERACTION. DYNAMIC MODEL GUIDANCE CONTINUES TO BE IN GOOD
AGREEMENT ON THE TRACK, LENDING TO HIGH CONFIDENCE IN THE JTWC
FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 181800Z IS 26 FEET. NEXT
WARNINGS AT 190900Z AND 192100Z.//
=========================================================================
WTPS32 PGTW 20150319 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 018//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 018
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
190600Z --- NEAR 14.7S 146.9E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON EYE FIXED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.7S 146.9E
---
FORECASTS:
12 HRS, VALID AT:
191800Z --- 14.6S 145.1E
MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
105 NM SOUTHEAST QUADRANT
105 NM SOUTHWEST QUADRANT
105 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 275 DEG/ 10 KTS
---
24 HRS, VALID AT:
200600Z --- 14.4S 143.0E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 36 HR POSIT: 280 DEG/ 09 KTS
---
36 HRS, VALID AT:
201800Z --- 14.1S 141.1E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 270 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
210600Z --- 14.1S 139.0E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 285 DEG/ 09 KTS
---
72 HRS, VALID AT:
220600Z --- 13.1S 135.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 96 HR POSIT: 270 DEG/ 09 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
230600Z --- 13.0S 131.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 120 HR POSIT: 260 DEG/ 06 KTS
---
120 HRS, VALID AT:
240600Z --- 13.5S 129.3E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
190900Z POSITION NEAR 14.7S 146.5E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 146 NM
NORTH-NORTHEAST OF CAIRNS, AUSTRALIA, HAS TRACKED WESTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A CLEAR 15 NM EYE AND GOOD BANDING WRAPPING INTO THE
CLOUD SYSTEM CENTER. A 190656Z SSMIS MICROWAVE IMAGE CONFIRMS THE
INCREASED CONVECTION WITHIN THE CORE WITH THE MAJORITY OF THE
CONVECTION IN THE SOUTHERN HALF OF THE SYSTEM. THE INITIAL POSITION
IS BASED ON THE EYE LOCATION WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY IS BASED ON THE CURRENT INTENSITY DVORAK ESTIMATES FROM
PTGW AND KNES. UPPER LEVEL ANALYSIS CONTINUES TO INDICATE A VERY
FAVORABLE ENVIRONMENT WITH A POINT SOURCE ABOVE TC 18P PROVIDING
RADIAL OUTFLOW AND LOW (5-10 KNOT) VERTICAL WIND SHEAR. TC NATHAN IS
TRACKING ALONG THE NORTHERN PERIPHERY OF A BUILDING DEEP LAYER SUB-
TROPICAL RIDGE (STR) OVER CENTRAL AUSTRALIA. THIS STR WILL CONTINUE
TO SERVE AS THE STEERING MECHANISM THROUGHOUT THE FORECAST PERIOD
MAINTAINING THE SYSTEMS WESTWARD TRACK. FAVORABLE ENVIRONMENTAL
CONDITIONS WILL PERSIST OVER THE NEXT 12 HOURS ALLOWING THE SYSTEM
SOME INTENSIFICATION PRIOR TO LANDFALL IN NORTHERN QUEENSLAND. TC
NATHAN WILL WEAKEN AS IT TRACKS ALONG THE CAPE YORK PENINSULA DUE TO
LAND INTERACTION. HOWEVER, DUE TO FAVORABLE CONDITIONS IN THE GULF
OF CARPENTARIA, FURTHER DISSIPATION OF TC NATHAN WHEN RETURNING BACK
OVER WATER WILL BE MARGINAL, WITH SOME MODELS ACTUALLY RE-
INTENSIFYING THE SYSTEM. THE SYSTEM IS FORECAST TO MAKE A SECONDARY
LANDFALL OVER CAPE ARNHEM AND WEAKEN ONCE AGAIN DUE TO LAND
INTERACTION. DYNAMIC MODEL GUIDANCE CONTINUES TO BE IN GOOD
AGREEMENT ON THE TRACK, LENDING TO HIGH CONFIDENCE IN THE JTWC
FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 190600Z IS 28 FEET. NEXT
WARNINGS AT 192100Z AND 200900Z.//
=========================================================================
WTPS32 PGTW 20150319 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 019//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 019
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
191800Z --- NEAR 14.7S 145.0E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 12 KTS
POSITION ACCURATE TO WITHIN 015 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.7S 145.0E
---
FORECASTS:
12 HRS, VALID AT:
200600Z --- 14.4S 143.2E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 285 DEG/ 09 KTS
---
24 HRS, VALID AT:
201800Z --- 13.9S 141.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 290 DEG/ 11 KTS
---
36 HRS, VALID AT:
210600Z --- 13.2S 139.2E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 290 DEG/ 10 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
211800Z --- 12.5S 137.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 290 DEG/ 07 KTS
---
72 HRS, VALID AT:
221800Z --- 11.5S 134.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 275 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
231800Z --- 11.4S 132.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 120 HR POSIT: 260 DEG/ 05 KTS
---
120 HRS, VALID AT:
241800Z --- 11.7S 130.5E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
192100Z POSITION NEAR 14.6S 144.5E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 140 NM
NORTH-NORTHWEST OF CAIRNS, AUSTRALIA HAS TRACKED WESTWARD AT 12
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A 9-NM EYE THAT IS BECOMING CLOUD FILLED
AS IT MAKES LANDFALL JUST NORTH OF CAPE FLATTERY. THE EIR LOOP ALSO
DEPICTS WELL-DEFINED DEEP CONVECTIVE BANDING WRAPPING INTO THE CLOUD
SYSTEM CENTER FROM THE NORTHERN AND SOUTHERN PERIPHERIES. A 191807Z
SSMIS 91GHZ MICROWAVE IMAGE SHOWS A SYMMETRIC EYE FEATURE WITH THE
DEEPEST CONVECTION ALONG THE SOUTHERN QUADRANT OF THE EYE WALL. THE
INITIAL POSITION IS BASED ON THE EYE POSITION IN THE EIR LOOP AND
MICROWAVE IMAGE WHILE BEING SUPPORTED BY THE WILLIS ISLAND RADAR
LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY WAS HELD AT 90
KNOTS BASED ON CONSENSUS CURRENT INTENSITY ESTIMATES FROM KNES AND
PGTW. THE UPPER LEVEL ENVIRONMENT REMAINS UNCHANGED WITH A POINT
SOURCE PROVIDING RADIAL OUTFLOW AND LOW (5-10 KNOT) VERTICAL WIND
SHEAR (VWS); HOWEVER, FRICTIONAL EFFECTS FROM MOVEMENT OVER CAPE
YORK IS BEGINNING TO WEAKEN THE SYSTEM. TC NATHAN IS TRACKING ALONG
THE NORTHERN PERIPHERY OF A DEEP LAYER SUB-TROPICAL RIDGE (STR) OVER
CENTRAL AUSTRALIA. TC 18P WILL REMAIN OVER LAND FOR 24 HOURS PRIOR
TO RE-EMERGING OVER WATER IN THE GULF OF CARPENTARIA. FROM TAU 24
THROUGH TAU 48, TC NATHAN IS FORECAST TO RE-INTENSIFY TO 70 KNOTS AS
IT ENCOUNTERS LOW VWS AND SSTS ABOVE 30C, PRIOR TO A SECONDARY
LANDFALL ALONG THE TIP OF CAPE ARNHEM NEAR TAU 48. BEYOND TAU 48 THE
SYSTEM WILL BEGIN TO ENCOUNTER MODERATE (15-20 KNOT) VWS AND REDUCED
OUTFLOW, WHICH BEGIN ANOTHER WEAKENING TREND. THIS WEAKENING WILL BE
GRADUAL DUE TO THE TRACK STRADDLING THE NORTHERN COAST PROVIDING
WARM SSTS. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT ON THE TRACK
THROUGH TAU 48. BEYOND TAU 48 NVGM, HWRF, AND COAMPS-TC RE-CURVE A
MUCH STRONGER CYCLONE POLEWARD AROUND THE STR WHILE THE REMAINING
GUIDANCE TRACKS A WEAKENING CYCLONE WESTWARD UNDER THE STEERING
INFLUENCE OF A LOW TO MID-LEVEL STR. WITH THE SYSTEM WEAKENING DUE
TO THE INCREASED VWS, THE LATTER OF THE TWO SCENARIOS IS MORE
PLAUSIBLE. HOWEVER, DUE TO THE BIFURCATION IN MODEL GUIDANCE BEYOND
TAU 48, THERE IS LOW CONFIDENCE IN THE OVERALL JTWC FORECAST.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 191800Z IS 25 FEET. NEXT
WARNINGS AT 200900Z AND 202100Z.//
=========================================================================
WTPS32 PGTW 20150320 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 020//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 020
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
200600Z --- NEAR 14.5S 143.2E
MOVEMENT PAST SIX HOURS - 275 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 14.5S 143.2E
---
FORECASTS:
12 HRS, VALID AT:
201800Z --- 14.1S 141.1E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 290 DEG/ 10 KTS
---
24 HRS, VALID AT:
210600Z --- 13.5S 139.2E
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 295 DEG/ 09 KTS
---
36 HRS, VALID AT:
211800Z --- 12.8S 137.6E
MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 300 DEG/ 08 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
220600Z --- 12.0S 136.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 285 DEG/ 06 KTS
---
72 HRS, VALID AT:
230600Z --- 11.3S 133.9E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 235 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
240600Z --- 12.4S 132.4E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 120 HR POSIT: 240 DEG/ 05 KTS
---
120 HRS, VALID AT:
250600Z --- 13.3S 130.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
200900Z POSITION NEAR 14.4S 142.7E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 208 NM
NORTHWEST OF CAIRNS, AUSTRALIA, HAS TRACKED WESTWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS WELL DEFINED CONVECTIVE BANDING WRAPPING INTO AN
OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION
IS BASED ON THE MSI LOOP AS WELL AS RADAR OBSERVATIONS FROM WEIPA.
THE INTENSITY HAS BEEN BROUGHT DOWN TO 70 KNOTS TO REFLECT THE LAND
EFFECTS ON TC NATHAN IN THE ABSENCE OF RELIABLE ABOVE-GRADIENT LEVEL
OBSERVATIONS IN THAT REGION. A 200644Z SSMIS 91GHZ MICROWAVE IMAGE
CONTINUES TO SHOW THE SYMMETRIC NATURE OF THE SYSTEM WITH GOOD
BANDING WRAPPING INTO THE LLCC. THE UPPER LEVEL ENVIRONMENT REMAINS
FAIRLY STAGNANT WITH DECENT RADIAL OUTFLOW AND LOW (5-10 KNOT)
VERTICAL WIND SHEAR (VWS). TC NATHAN CONTINUES TO TRACK ALONG
THE NORTHERN PERIPHERY OF A DEEP LAYER SUB-TROPICAL RIDGE (STR) OVER
CENTRAL AUSTRALIA. AS TC 18P WILL REMAIN OVER THE CAPE YORK
PENINSULA FOR THE NEXT 10 HOURS, EXPECT SOME FURTHER DEGRADATION TO
THE INTENSITY OF THE SYSTEM. UPON RE-EMERGING OVER WATER IN THE GULF
OF CARPENTARIA, THERE IS EXPECTED TO BE SOME RE-INTENSIFICATION AS
CONDITIONS IN THE GULF ARE FAVORABLE FOR DEVELOPMENT DUE TO LOW VWS
AND SSTS ABOVE 30C. AS TC NATHAN MAKES A SECONDARY LANDFALL ALONG
THE GOVE PENINSULA, EXPECT SOME DECAY AS THE TC WILL ENCOUNTER
MODERATE (15-20 KNOT) VWS AND REDUCED OUTFLOW. DYNAMIC MODEL
GUIDANCE IS IN TIGHT AGREEMENT ON THE TRACK THROUGH TAU 48. BEYOND
TAU 48 THERE IS A OPENING IN THE DYNAMIC GUIDANCE SPREAD AS THE
SYSTEM TRACKS POLEWARD AROUND THE STR AND THE RIDGE TRACKS TO THE
EAST. THE EXTENT OF THE TURNING OF THE SYSTEM IS IN QUESTION,
WHETHER IF TC NATHAN WILL RE-EMERGE OVER THE OCEAN WEST OF DARWIN OR
TRACKS DEEPER INTO THE NORTHERN TERRITORY. DUE TO THIS DISAGREEMENT
WITHIN THE MODELS IN THE EXTENDED FORECAST, THERE IS LOW CONFIDENCE
IN THE OVERALL JTWC FORECAST. NEXT WARNINGS AT 202100Z AND 210900Z.//
=========================================================================
WTPS32 PGTW 20150320 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 021//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 021
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
201800Z --- NEAR 14.0S 141.5E
MOVEMENT PAST SIX HOURS - 290 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 14.0S 141.5E
---
FORECASTS:
12 HRS, VALID AT:
210600Z --- 13.5S 139.7E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 290 DEG/ 09 KTS
---
24 HRS, VALID AT:
211800Z --- 12.9S 138.0E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 295 DEG/ 07 KTS
---
36 HRS, VALID AT:
220600Z --- 12.3S 136.7E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 295 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
221800Z --- 11.7S 135.4E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 285 DEG/ 04 KTS
---
72 HRS, VALID AT:
231800Z --- 11.3S 133.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 250 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
241800Z --- 11.9S 131.8E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 120 HR POSIT: 240 DEG/ 05 KTS
---
120 HRS, VALID AT:
251800Z --- 13.0S 129.9E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
202100Z POSITION NEAR 13.9S 141.0E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 291 NM
EAST-SOUTHEAST OF GOVE AIRPORT, AUSTRALIA, HAS TRACKED WEST-
NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS DIMINISHING DEEP CONVECTION OVER
A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION AS IT CROSSES THE CAPE
YORK PENINSULA. THE CURRENT POSITION IS BASED ON SATELLITE FIXES
FROM PGTW, KNES AND ABRF AS WELL AS THE RADAR LOOP FROM WEIPA. THE
INITIAL INTENSITY IS ASSESSED AT 40 KNOTS BASED ON AN OVERALL
ASSESSEMENT OF THE CURRENT STRUCTURE AND SURFACE OBSERVATIONS FOR
QUEENSLAND FROM THE AUSTRALIAN BUREAU OF METEOROLOGY. UPPER-LEVEL
ANALYSIS INDICATES TC 18P REMAINS IN FAVORABLE ENVIRONMENT WITH A
POINT-SOURCE DIRECTLY OVER THE SYSTEM AND LOW (05 TO 10 KNOT)
VERTICAL WIND SHEAR. TC NATHAN CONTINUES TO TRACK ALONG
THE NORTHERN PERIPHERY OF A DEEP LAYER SUB-TROPICAL RIDGE (STR)
LOCATED OVER CENTRAL AUSTRALIA. UPON RE-EMERGING OVER WATER IN THE
GULF OF CARPENTARIA, TC 18P IS EXPECTED TO REINTENSIFY AS FAVORABLE
CONDITIONS PERSIST. THE SYSTEM IS EXPECTED TO MAKE A SECOND LANDFALL
AROUND TAU 36 AND BEGIN ITS WEAKENING TREND. AVAILABLE MODEL
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 LENDING HIGH CONFIDENCE
IN THE TRACK FORECAST. HOWEVER, THERE ARE SOME DIFFERENCES IN THE
EXTENDED TAUS DUE TO THE EXTENT OF THE STEERING STR. FOR THIS
REASON, THERE IS LOW CONFIDENCE IN THE EXTENDED PERIOD OF THE
FORECAST. NEXT WARNINGS AT 210900Z AND 212100Z.//
=========================================================================
WTPS32 PGTW 20150321 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 022//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 022
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
210600Z --- NEAR 13.7S 139.3E
MOVEMENT PAST SIX HOURS - 270 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.7S 139.3E
---
FORECASTS:
12 HRS, VALID AT:
211800Z --- 13.0S 137.5E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 295 DEG/ 09 KTS
---
24 HRS, VALID AT:
220600Z --- 12.2S 135.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 36 HR POSIT: 295 DEG/ 07 KTS
---
36 HRS, VALID AT:
221800Z --- 11.6S 134.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 285 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
230600Z --- 11.4S 133.7E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 250 DEG/ 03 KTS
---
72 HRS, VALID AT:
240600Z --- 11.8S 132.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 96 HR POSIT: 230 DEG/ 04 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
250600Z --- 12.7S 131.6E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 120 HR POSIT: 235 DEG/ 04 KTS
---
120 HRS, VALID AT:
260600Z --- 13.6S 130.3E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
210900Z POSITION NEAR 13.5S 138.8E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 496 NM EAST
OF DARWIN, AUSTRALIA, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE
SYSTEM HAS MAINTAINED OVERALL CONVECTIVE STRENGTH AS IT DRIFTED
ACROSS THE GULF OF CARPENTARIA. THE INITIAL POSITION IS BASED ON THE
MSI AND A COMPOSITE RADAR LOOP FROM GOVE AIRPORT WITH FAIR
CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT
OF DVORAK ESTIMATES FROM PGTW, KNES, AND ADRM. UPPER-LEVEL ANALYSIS
INDICATES TC 18P REMAINS IN A FAVORABLE ENVIRONMENT WITH A
POINT-SOURCE ANTICYCLONE DIRECTLY OVERHEAD THAT IS ENHANCING OUTFLOW,
AND LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR. THE CYCLONE IS TRACKING
ALONG THE NORTHERN PERIPHERY OF A DEEP LAYERED SUB-TROPICAL RIDGE TO
THE SOUTH, OVER CENTRAL AUSTRALIA. IT IS EXPECTED TO DRAG ACROSS THE
COASTLINE OF THE NORTHERN TERRITORY PRIOR TO DIPPING INLAND BEFORE
DARWIN AND DISSIPATE BY TAU 120. AVAILABLE MODEL GUIDANCE IS IN
OVERALL GOOD AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC TRACK
FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 210600Z IS 13 FEET. NEXT
WARNINGS AT 212100Z AND 220900Z.//
=========================================================================
WTPS32 PGTW 20150321 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 023//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 023
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
211800Z --- NEAR 13.1S 137.5E
MOVEMENT PAST SIX HOURS - 275 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
085 NM NORTHWEST QUADRANT
REPEAT POSIT: 13.1S 137.5E
---
FORECASTS:
12 HRS, VALID AT:
220600Z --- 12.2S 136.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 300 DEG/ 06 KTS
---
24 HRS, VALID AT:
221800Z --- 11.6S 134.9E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 285 DEG/ 04 KTS
---
36 HRS, VALID AT:
230600Z --- 11.4S 134.2E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 260 DEG/ 03 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
231800Z --- 11.5S 133.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 245 DEG/ 02 KTS
---
72 HRS, VALID AT:
241800Z --- 11.9S 132.8E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 96 HR POSIT: 215 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
251800Z --- 13.4S 131.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
212100Z POSITION NEAR 12.9S 137.1E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 388 NM EAST
OF DARWIN, AUSTRALIA, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS
PERSISTENT CENTRAL CONVECTION WITH SPIRAL BANDS WRAPPING INTO THE
LOW-LEVEL CIRCULATION CENTER. A 211628Z NOAA-19 COMPOSITE MICROWAVE
IMAGE ALSO REVEALS TIGHTLY-CURVED CONVECTIVE BANDING WITH A
MICROWAVE EYE. THE CURRENT POSITION IS BASED ON THE SATELLITE FIXES
FROM PGTW AND KNES AS WELL AS THE GOVE RADAR LOOP WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 55 KNOTS IS BASED ON CONSENSUS
DVORAK ESTIMATES OF T3.5 FROM PGTW AND KNES. UPPER-LEVEL ANALYSIS
INDICATES TC NATHAN REMAINS IN A FAVORABLE ENVIRONMENT WITH A
POINT-SOURCE DIRECTLY OVERHEAD THAT IS SUSTAINING THE DEEP
CONVECTION AND PROVIDING RADIAL OUTFLOW. TC 18P IS CURRENTLY
TRACKING ALONG THE NORTHERN PERIPHERY OF A DEEP LAYERED SUB-TROPICAL
RIDGE TO THE SOUTH, OVER CENTRAL AUSTRALIA. THE CYCLONE IS EXPECTED
TO GRADUALLY WEAKEN AS IT DRAGS ACROSS THE COASTLINE OF THE NORTHERN
TERRITORY. TC NATHAN IS FORECAST TO DISSIPATE BY THE END OF THE
FORECAST PERIOD. AVAILABLE MODEL GUIDANCE IS IN OVERALL GOOD
AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 211800Z IS 14 FEET. NEXT WARNINGS
AT 220900Z AND 222100Z. REFER TO TROPICAL CYCLONE 20P (TWENTY)
WARNINGS (WTPS31 PGTW) FOR TWELVE-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150322 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 024//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 024
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
220600Z --- NEAR 12.2S 135.9E
MOVEMENT PAST SIX HOURS - 295 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 025 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 12.2S 135.9E
---
FORECASTS:
12 HRS, VALID AT:
221800Z --- 11.5S 134.8E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 290 DEG/ 05 KTS
---
24 HRS, VALID AT:
230600Z --- 11.2S 133.9E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 255 DEG/ 04 KTS
---
36 HRS, VALID AT:
231800Z --- 11.4S 133.1E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 230 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
240600Z --- 12.0S 132.3E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 230 DEG/ 05 KTS
---
72 HRS, VALID AT:
250600Z --- 13.2S 130.9E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 96 HR POSIT: 260 DEG/ 05 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
260600Z --- 13.6S 129.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 265 DEG/ 06 KTS
---
120 HRS, VALID AT:
270600Z --- 13.7S 126.5E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
220900Z POSITION NEAR 12.0S 135.6E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 294 NM EAST OF
DARWIN, AUSTRALIA, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER
THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS THE SYSTEM HAS MAINTAINED AN OVERALL CONVECTIVE SIGNATURE WITH
A SLIGHT WARMING OF THE CENTRAL DENSE OVERCAST (CDO) AS IT DRAGGED
JUST OFF THE COAST OF THE NORTHERN TERRITORY. THE INITIAL POSITION IS
BASED ON THE ABOVE ANIMATION AND ON A COMPOSITE RADAR LOOP FROM GOVE
AIRPORT WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN
OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND NEARBY SURFACE
OBSERVATIONS AND TAKES INTO ACCOUNT THE SLIGHTLY WEAKENED STATE OF
THE CYCLONE. UPPER-LEVEL ANALYSIS INDICATES TC NATHAN REMAINS IN A
FAVORABLE ENVIRONMENT WITH A POINT-SOURCE ANTICYCLONE DIRECTLY
OVERHEAD THAT IS PROVIDING RADIAL OUTFLOW TO THE CDO. TC 18P IS
TRACKING ALONG THE NORTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL
RIDGE (STR) TO THE SOUTH, OVER CENTRAL AUSTRALIA. AFTER TAU 36, THE
STR WILL WEAKEN WITH THE APPROACH OF A MIGRATORY MID-LATITUDE TROUGH
FROM THE SOUTHWEST. THIS WILL CAUSE TC 18P TO MOMENTARILY TRACK
SOUTHWESTWARD INLAND TOWARDS DARWIN BEFORE RETURNING TO A WESTWARD
TRAJECTORY AFTER TAU 72 THEN BACK INTO WATER - THIS TIME THE SOUTH
INDIAN OCEAN. FAVORABLE UPPER LEVEL CONDITIONS WILL PROMOTE A
MODERATE INTENSIFICATION OVER THE NEXT 24 HOURS, PEAKING AT 65 KNOTS
BEFORE TRACKING INLAND. TC NATHAN WILL ERODE AS IT DRAGS OVER LAND
BUT WILL EMERGE IN THE SOUTH INDIAN OCEAN AT 35 KNOTS AND POISED FOR
RE-INTENSIFICATION. AVAILABLE MODEL GUIDANCE IS IN OVERALL GOOD
AGREEMENT LENDING FAIR CONFIDENCE IN THE JTWC TRACK FORECAST. NEXT
WARNINGS AT 222100Z AND 230900Z. REFER TO TROPICAL CYCLONE 20P
(REUBEN) WARNINGS (WTPS31 PGTW) FOR 12-HOURLY UPDATES.//
=========================================================================
WTPS32 PGTW 20150322 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 025//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 025
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
221800Z --- NEAR 11.5S 134.9E
MOVEMENT PAST SIX HOURS - 305 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 11.5S 134.9E
---
FORECASTS:
12 HRS, VALID AT:
230600Z --- 11.2S 134.0E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 265 DEG/ 04 KTS
---
24 HRS, VALID AT:
231800Z --- 11.3S 133.1E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT
010 NM SOUTHEAST QUADRANT
010 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 230 DEG/ 03 KTS
---
36 HRS, VALID AT:
240600Z --- 11.7S 132.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 230 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
241800Z --- 12.3S 131.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 245 DEG/ 04 KTS
---
72 HRS, VALID AT:
251800Z --- 13.0S 130.3E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 96 HR POSIT: 265 DEG/ 06 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
261800Z --- 13.2S 128.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 265 DEG/ 10 KTS
---
120 HRS, VALID AT:
271800Z --- 13.6S 124.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
222100Z POSITION NEAR 11.4S 134.7E.
TROPICAL CYCLONE 18P (NATHAN), LOCATED APPROXIMATELY 242 NM EAST-
NORTHEAST OF DARWIN, AUSTRALIA, HAS TRACKED NORTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 221800Z IS 10 FEET. NEXT
WARNINGS AT 230900Z AND 232100Z.
=========================================================================
WTXS31 PGTW 20150323 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 026//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 026
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
230600Z --- NEAR 11.4S 134.3E
MOVEMENT PAST SIX HOURS - 280 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND RADAR
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 11.4S 134.3E
---
FORECASTS:
12 HRS, VALID AT:
231800Z --- 11.5S 133.6E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
015 NM SOUTHEAST QUADRANT
015 NM SOUTHWEST QUADRANT
015 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 235 DEG/ 04 KTS
---
24 HRS, VALID AT:
240600Z --- 11.9S 133.0E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 36 HR POSIT: 235 DEG/ 04 KTS
---
36 HRS, VALID AT:
241800Z --- 12.4S 132.3E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 255 DEG/ 05 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
250600Z --- 12.7S 131.3E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 260 DEG/ 06 KTS
---
72 HRS, VALID AT:
260600Z --- 13.0S 128.9E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 96 HR POSIT: 270 DEG/ 07 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
270600Z --- 13.0S 125.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 265 DEG/ 08 KTS
---
120 HRS, VALID AT:
280600Z --- 13.3S 122.5E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
230900Z POSITION NEAR 11.4S 134.1E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 210 NM
EAST-NORTHEAST OF DARWIN, AUSTRALIA, HAS TRACKED WESTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE AS IT
DRIFTED JUST OFFSHORE OF THE NORTHERN TERRITORY. THE INITIAL POSITION
IS BASED ON A COMPOSITE RADAR LOOP FROM GOVE AIRPORT WITH GOOD
CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT
OF DVORAK ESTIMATES FROM PGTW, ADRM, AND KNES. UPPER-
LEVEL ANALYSIS INDICATES TC NATHAN REMAINS IN A FAVORABLE ENVIRONMENT
WITH A POINT-SOURCE ANTICYCLONE DIRECTLY OVERHEAD THAT
IS PROVIDING RADIAL OUTFLOW. TC 18P IS TRACKING ALONG THE NORTHERN
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE SOUTH,
OVER CENTRAL AUSTRALIA. AFTER TAU 12, THE STR WILL WEAKEN SLIGHTLY
WITH THE APPROACH OF A MIGRATORY MID-LATITUDE TROUGH FROM THE
SOUTHWEST. THIS WILL CAUSE TC 18P TO MOMENTARILY TRACK SOUTHWESTWARD
INLAND TOWARDS DARWIN BEFORE RETURNING TO A WESTWARD TRAJECTORY BY
TAU 48. TC NATHAN WILL MAKE LANDFALL SHORTLY AFTER TAU 12 AND WILL
ERODE AS IT DRAGS OVER LAND BUT WILL EMERGE IN THE SOUTH INDIAN
OCEAN AFTER TAU 48 AND SLOWLY RE-INTENSIFY. AVAILABLE MODEL GUIDANCE
REMAINS IN GOOD AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC TRACK
FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 230600Z IS 18 FEET. NEXT
WARNINGS AT 232100Z AND 240900Z.//
=========================================================================
WTXS31 PGTW 20150323 21:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 027//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 027
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
231800Z --- NEAR 11.6S 133.5E
MOVEMENT PAST SIX HOURS - 255 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
REPEAT POSIT: 11.6S 133.5E
---
FORECASTS:
12 HRS, VALID AT:
240600Z --- 11.9S 132.8E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 24 HR POSIT: 255 DEG/ 05 KTS
---
24 HRS, VALID AT:
241800Z --- 12.2S 131.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 260 DEG/ 06 KTS
---
36 HRS, VALID AT:
250600Z --- 12.4S 130.5E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 48 HR POSIT: 265 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
251800Z --- 12.5S 129.0E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 72 HR POSIT: 265 DEG/ 09 KTS
---
72 HRS, VALID AT:
261800Z --- 12.9S 125.5E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 265 DEG/ 09 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
271800Z --- 13.3S 121.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 250 DEG/ 09 KTS
---
120 HRS, VALID AT:
281800Z --- 14.4S 118.5E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
232100Z POSITION NEAR 11.7S 133.3E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 162 NM
EAST-NORTHEAST OF DARWIN, AUSTRALIA HAS TRACKED WEST-SOUTHWESTWARD
AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
(EIR) SATELLITE IMAGERY DEPICTS WEAKENED CONVECTION DISPLACED TO THE
SOUTH OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). A
231732Z SSMI MICROWAVE IMAGE SHOWS A TIGHTLY WRAPPED LLCC, DESPITE
THE LAND INTERACTION, AND FURTHER DEPICTS AN OVERALL REDUCED
CONVECTIVE SIGNATURE. UPPER LEVEL ANALYSIS INDICATES A MARGINALLY
FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10-20 KNOT) NORTH-
NORTHWESTERLY VERTICAL WIND SHEAR (VWS) WITH GOOD POLEWARD OUTFLOW
AS EVIDENT ON WATER VAPOR IMAGERY. THE INITIAL POSITION IS BASED ON
THE AFOREMENTIONED MICROWAVE IMAGE AND EIR LOOP, AS WELL AS, THE
WARRUWI RADAR LOOP AND OBSERVATIONS ALONG THE ARNHEM LAND COASTLINE.
THE INITIAL INTENSITY OF 50 KNOTS IS BASED ON AN AVERAGE OF CURRENT
INTENSITY ESTIMATES FROM PGTW, ADRM, AND KNES. TC 18P CONTINUES TO
TRACK ALONG THE NORTHERN PERIPHERY OF A DEEP LAYER SUB-TROPICAL
RIDGE (STR). HOWEVER, IT IS CURRENTLY TRACKING WEST-SOUTHWESTWARD
AND ITS FORWARD SPEED HAS DECREASED AS THE STR HAS WEAKENED DUE TO A
PASSING SHORTWAVE TROUGH TO THE SOUTH. ONCE THE TROUGH PASSES, THE
STR IS FORECAST TO BUILD BACK IN, CHANGING THE TRACK BACK TO A
WESTWARD TRAJECTORY. TC NATHAN IS EXPECTED TO CONTINUE TO WEAKEN
OVER THE NEXT 36 TO 48 HOURS DUE TO LAND INTERACTION ALONG THE
NORTHERN COAST OF ARNHEM LAND PRIOR TO EMERGING IN THE TIMOR SEA.
BEYOND TAU 48, THE SYSTEM WILL SLOWLY RE-INTENSIFY AS IT IS EXPOSED
TO SEA SURFACE TEMPERATURES ABOVE 31 CELSIUS AND CONTINUES TO HAVE A
MARGINALLY FAVORABLE UPPER LEVEL ENVIRONMENT. BY THE END OF THE
FORECAST PERIOD THE CYCLONE WILL GAIN AN ENHANCED POLEWARD OUTFLOW
CHANNEL DUE TO AN UPPER LEVEL HIGH AMPLITUDE TROUGH APPROACHING FROM
THE WEST. AT THIS TIME, THE SYSTEM WILL ALSO BEGIN TO ROUND THE
NORTHWESTERN PERIPHERY OF THE STR. DYNAMIC MODEL GUIDANCE REMAINS IN
TIGHT AGREEMENT; THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 231800Z IS 15
FEET. NEXT WARNINGS AT 240900Z AND 242100Z.//
=========================================================================
WTXS31 PGTW 20150324 09:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18P (NATHAN) WARNING NR 028//
RMKS/
1. TROPICAL CYCLONE 18P (NATHAN) WARNING NR 028
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
240600Z --- NEAR 12.5S 132.4E
MOVEMENT PAST SIX HOURS - 245 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE, RADAR AND SYNOPTIC DATA
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
REPEAT POSIT: 12.5S 132.4E
---
FORECASTS:
12 HRS, VALID AT:
241800Z --- 12.7S 131.1E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
240900Z POSITION NEAR 12.5S 132.1E.
TROPICAL CYCLONE (TC) 18P (NATHAN), LOCATED APPROXIMATELY 88 NM EAST
OF DARWIN, AUSTRALIA, HAS TRACKED WEST-SOUTHWESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. TC 18P HAS CONTINUED TO TRACK INLAND OVER
THE PAST 12 HOURS WHILE RAPIDLY WEAKENING. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY INDICATES AN EXPOSED, BROADENING LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH ISOLATED DEEP CONVECTION SHEARED
SOUTHEASTWARD. RADAR IMAGERY FROM THE DARWIN RADAR PROVIDES FURTHER
EVIDENCE OF THE WEAKENED CONVECTIVE STRUCTURE WITH BROAD, FRAGMENTED
BANDING WRAPPING INTO A WEAKLY-DEFINED CENTER. MULTIPLE SURFACE
OBSERVATIONS IN THE REGION INDICATE MAXIMUM SUSTAINED WINDS
(ADJUSTED TO 1-MINUTE AVERAGE) OF ONLY 15 TO 25 KNOTS. ADDITIONALLY,
THE MOST RECENT DARWIN SOUNDING SHOWS SIGNIFICANT DRY AIR THROUGH
THE COLUMN WHILE THE LATEST TOTAL PRECIPITABLE WATER LOOP INDICATES
DRY AIR ADVECTING ALONG THE WESTERN SEMI-CIRCLE OF THE SYSTEM. THE
SYSTEM IS ALSO LOCATED UNDER NORTHWESTERLY VERTICAL WIND SHEAR,
WHICH IS FORECAST TO PERSIST FOR 2 TO 3 DAYS. THERFORE, THE SYSTEM
IS FORECAST TO CONTINUE WEAKENING THROUGH AT LEAST TAU 48 WITH SOME
POTENTIAL FOR RE-DEVELOPMENT AFTER TAU 60 TO 72 AS THE ENVIRONMENTAL
CONDITIONS IMPROVE. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE
JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY
MONITORED FOR SIGNS OF REGENERATION.//
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| Document: tropical_cyclone_nathan.htm | Updated: 25 March 2015 |