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Australian Weather Mailing List Archives: 15th October 1998 |
Date: Thu, 15 Oct 1998 00:00:47 +1000 From: Greg BrowningTo: aussie-weather at world.std.com Subject: aussie-weather: Melbourne-Here's Hoping Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Dane, good to hear from a fellow weather nut in good ol' Melbourne Town. As soon as I reinstall my Excell software I will, with great interest, check out the Melb storm data- thanks heaps for making it available. Since Jane seems also to be hopeful of a stormy weekend we Melburnians should keep a close eye on things to keep the others informed. Let's hope those MRF's prove a bit more fruitful this time! Greg Browning -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 10:23:59 +1000 From: david.croan at agal.gov.au (David Croan) Subject: aussie-weather: SC storm spacing To: aussie-weather at world.std.com, Paul Graham Content-Description: cc:Mail note part Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com I am sure that most of you have read the report in storm news of the tornadic outbreak which occurred in the central west/north west slopes of NSW on 29th September 1996. The satpic shows a striking line of supercells teardrops - I realise that the scale of this image is quite different from the Brisbane radar and not all cells in the line on the satellite image are confirmed supercells, nevertheless, the proximity of these storms seems rather close.. ______________________________ Reply Separator _________________________________ Subject: Re: aussie-weather: Bow Echo... Author: Paul Graham at agal-email Date: 14/10/98 6:42 PM Quite true: storm spacing can affect the severity depending on how much energy is available. I remember reading about the report from the Bureau of Meteorology on the March, 1990 Hailstorm in Sydney which is believed to have fit the description of high precipitation supercell. PPI Radar scans are shown as part of the report and several cells are detected moving in the same direction as the severe cell which passed over Sydney. The authors suggest that, since supercell type storms have an anomalous movement when compared with short lived single or multi type storms, the other storms that day may also have been severe (they moved through sparsley populated areas). - Paul. On Wed, 14 Oct 1998, Anthony Cornelius wrote: > Paul - I was thinking the same thing that perhaps both cells were infact > supercells, but in my opinion, it's quite rare to have a severe > supercell quite close to another severe cell, let alone two supercells! > As supercells generally form where there are no storms, the mesocyclone > storm hit Fortitude Valley and Kangaroo Point areas - giving them in my > opinion an F1 (F2 possible?) tornado. The bow echo cell was the one > that went over myself. Although I don't have as much experience as > other people in wx because I am much younger then most - but what do > other people think about the possibility of 2 supercells almost > side-by-side? > > Anthony Cornelius > > Paul Graham wrote: > > > Yes, one of the cells (perhaps the Brisbane storm?) has a very > > distinctive > > and persistent bow echo - probably a supercell - and another also > > shows a > > hook consistent with a mesocyclone. Interestingly, most of the cells > > seem > > to be moving in the same direction - all supercells? There doesn't > > seem > > to be any indication of "splitting" either. > > > > Thanks for the radar images Michael. - Paul. -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 10:48:36 +1000 From: Michael Scollay Organization: Telstra Strategy & Research X-Accept-Language: en To: Aussie Weather Subject: aussie-weather: 19981015-20 MRF Storm Potential Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Looking at the MRF's today makes me wonder whether storm-chasers should be heading into the interior around NT (Alice Springs) through Lake Eyer into NW & Central-NSW for the next six days or so. As long as this NCEP/MRF stuff has been on the 'net, I've not seen so much precipitation and precipitable water forecasts through this area for such an extended time. Coupled with such a severe trough gives the potential for severe storms in this region. As in Sept 1996, these are conditions that might produce tornados. Satpic of 199810142225 already shows a storm build-up in Central Australia without the front. Bring a strong front into the picture and wullah! The inland also gives clear views for photography at a distance albeit through sparse access, quite unlike "tornado alley" in the US of A. Major pity is that the expected frontal system looks like loosing some of its severe storm potential for NE,E-NSW/S-QLD the further it moves NE. The SE edge around the NE-VIC/SE-NSW region both west of and on the ranges has the greatest precipitation forecast on Monday moving to N, Central & NE-NSW inland and E-NSW coastal on Tuesday. ,-_|\ Michael Scollay mailto:michael.scollay at telstra.com.au / \ Telstra Technology 4/231 Elizabeth St. Sydney NSW 2000 \_,^._* Strategy & Research snail: Locked Bag 6682 GPO Sydney 1100 v Sydney NSW Australia +61 2 9287 5233P +61 2 9287 5031F -------------------------------------------------------------------------------------- From: Blair Trewin Subject: aussie-weather: Stroms in southern NT To: aussie-weather at world.std.com (Aussie Weather) Date: Thu, 15 Oct 1998 14:49:39 +1000 (EST) Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Looks like some impressive storms on the radar in the Alice Springs area and to the west - quite a few areas of 40mm/hour plus indicated. No warnings out, although IIRC NT don't do thunderstorm warnings (except maybe for the Darwin metro area?). The 0430 UTC METAR for Alice Springs was reporting a heavy shower to the west. I'll be interested to see the rainfall totals on the 1500 bulletin. Blair Trewin -------------------------------------------------------------------------------------- From: "James Chambers" To: "Aussie Weather" Subject: aussie-weather: confirmed supercell Date: Thu, 15 Oct 1998 15:45:06 +1000 X-Msmail-Priority: Normal X-Mimeole: Produced By Microsoft MimeOLE V4.72.3110.3 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi all I just talked to a guy in the severe weather section at the Brisbane Weather Bureau and he confirmed that it was a supercell. He said the cell responsible that was heading towards Brisbane suddenly intensified just after 2pm when it hit the seabreeze front. Dozens of people he said noticed the rotating mesocyclone (I didn't because rain spoiled my view) and the amateur video showing the swirls of debris was probably a 'young' tornado that wasn't able to reach full strength. He seemed hesitant to call it a tornado. I told him it either was or it isn't. He half agreed to that! I asked him about the damage in Warwick and straight line winds were responsible. There was no evidence of a tornado. Soon I hope to have a full report on the events of Tuesday, October 13 1998 on my site. Catch ya later James from Brissie (storm capital of the Universe!) Not. My place has had about 15 Thunderdays this year, which isn't so bad. http://www.ozemail.com.au/~jamestorm/bristorm.html -------------------------------------------------------------------------------------- From: "James Chambers" To: "Aussie Weather" Subject: aussie-weather: storm warnings in victoria Date: Thu, 15 Oct 1998 15:55:39 +1000 X-Msmail-Priority: Normal X-Mimeole: Produced By Microsoft MimeOLE V4.72.3110.3 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hello again I just noticed an old storm warning for Melbourne. Can anyone tell me why the Melbourne Weather Bureau warn for non-severe t'storms in Victoria? I'm thinking if they suddenly warn for likely severe t'storms maybe not so many people will listen, thinking it's just another weak storm. Maybe they have more money down there and can afford to warn for storms that may cause injury because of lightning strikes...I'm at a loss I would like some feedback on this because its happened time and time again. James in Bris www.ozemail.com.au/~jamestorm/bristorm.html -------------------------------------------------------------------------------------- From: "Nick Sykes" To: "aussie-weather" Subject: aussie-weather: Severe Weather in Melbourne Saturday Date: Thu, 15 Oct 1998 16:36:26 +1000 X-Msmail-Priority: Normal X-Mimeole: Produced By Microsoft MimeOLE V4.72.3110.3 X-Mime-Autoconverted: from 8bit to quoted-printable by minotaur.labyrinth.net.au id QAA15015 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com X-MIME-Autoconverted: from quoted-printable to 8bit by penman.es.mq.edu.au id QAA21636 Hi all, just read the Victorian forecast for Saturday, sounding pretty interesting, does anyone think there is a chance of severe thunderstorms im Melbourne Saturday. BUREAU OF METEOROLOGY VICTORIAN REGIONAL OFFICE Issued at 1620 on Thursday the 15th of October 1998 Warnings Nil. Victoria A high pressure system will drift across Victoria overnight to lie east of the state later on Friday. After a fairly cold night with fog patches, Friday will be fine and generally sunny. Warmer northerly winds will develop in the west but light winds and coastal seabreezes will prevail in central and eastern parts. UV INDEX: Friday 7 [Very High] Saturday will be warm to very warm with strengthening northerly winds ahead of an approaching cold front. The front will reach the west in the afternoon then extend eastwards in the evening bringing cooler gusty west to southwest winds, patchy rain and local thunder. The cold front will move through eastern Victoria on Sunday and there will be some rain in all districts. Winds will be cool moderate to fresh westerly. West to southwesterly winds will continue on Monday as another cold front moves through Victoria and there will be scattered showers, mainly over southern and mountain districts. Melbourne Tonight and Friday Fine. A mainly sunny day with light wind, tending northerly, and afternoon sea breezes. Min 8 Max 22 Saturday Late change with thundery showers. Min 13 Max 29 Sunday Rain at times. Min 15 Max 18 Monday Few showers. Min 10 Max 16 Port Phillip Bay and Western Port Tonight and Friday Southerly wind at about 10 knots becoming variable at 5 knots overnight. Wind tending northerly tomorrow to 10 knots with afternoon seabreezes of similar strength. Waves to about half a metre. Saturday Strengthening northerly wind ahead a late gusty west to southwest change. Sunday Moderate to fresh west to southwest wind. Monday Moderate to fresh west to southwest wind. Headline Melbourne: Fine. Mainly sunny. Headline Victoria: Fine but for local morning fog. Cold night. Mild to warm -------------------------------------------------------------------------------------- From: paulmoss at tpgi.com.au Date: Thu, 15 Oct 1998 19:08:17 +1000 To: aussie-weather at world.std.com Subject: aussie-weather: Re: aussie-weather Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Howdy all. Eeveryones gone quiet tonight?? How was the meeting last night on IRC? Any interesting points raised? Paul from Taree. -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 19:22:48 +1000 From: Matthew Piper X-Accept-Language: en To: aussie-weather at world.std.com Subject: Re: aussie-weather: Re: aussie-weather Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Paul, Last nights IRC discussed the Brisbane storm, Super Typhoon Zeb and Severe Storms in General. Matthew paulmoss at tpgi.com.au wrote: > Howdy all. Eeveryones gone quiet tonight?? How was the meeting last night on > IRC? Any interesting points raised? > > Paul from Taree. -------------------------------------------------------------------------------------- From: paulmoss at tpgi.com.au Date: Thu, 15 Oct 1998 19:27:53 +1000 To: aussie-weather at world.std.com Subject: aussie-weather: (no subject) Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com lAURIER: Thanx for the info on the upper air diagrams. Excellent stuff. Makes it alot clearer now. I will fire off questions as they come to mind and the 1st one is: (for anybody to answer!) What sort of cape levels do you require for thunderstorms/sever e storms?? Is there a general guide? Regards, Paul from Taree -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 21:09:08 +1000 From: Anthony Cornelius To: aussie-weather at world.std.com Subject: Re: aussie-weather: Severe Weather in Melbourne Saturday X-Mime-Autoconverted: from 8bit to quoted-printable by bomber.stealth.com.au id VAA05934 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com X-MIME-Autoconverted: from quoted-printable to 8bit by penman.es.mq.edu.au id VAA00440 Hi Nick - I noticed that Melbourne is forecasted to go down to 13 for a minimum, this is actually quite cool and indicates that the DP is relatively low, which really does limit the possibility of storms, let alone severe storms in itself. NGP is showing some fairly high levels of expected precipitation and the bar is expected to dip below 1000 - where as MRF has the pressure dipping to around 1004. This is good, however there are high levels of moisture predicted in the upper atmosphere indicated by the NGP models - MRF also shows this, but acutally has the entire system moving through later then NGP. Although my personal favourite models is MRF, the new MRF models won't be out for another hour or two, and the NGP models are more up to date. The problem with high moisture levels in the upper atmosphere is that rain will tend to prevail over t'storms. TT's will be around 45 - which is the threshold for severe t'storms. The models also show some good vertical uplift for storms. A nice strong, divergent jetstream is also present - another key occurrence for severe t'storms! However the main problems are these: 1) The air in Melbourne will probably be too dry, you will be getting N'ly and NW'ly winds which will certainly dry the air out! (I guess this is one reason why SE QLD is lucky, NE, N and NW winds are all moist, as NW winds run about parallel to the coast line - well, almost) 2) High levels of moisture in the amtmosphere - rain more likely, the problem with rain is that it never just "appears" like storms do, rather you get a period of a few hours where clouds thicken and can sometimes cool the area down. Rain can also surpress updrafts in my experience. Your only saving grace could be the sea breeze for coastal areas, but it is unlikely this will be enough for any severe t'storm development. IF you do get storms I personally don't believe they'll be severe, but in the end, all we have are forecast models that basically say "if the weather patterns do what they should, this will happen" and as well all know, weather rarely does what it should! Anthony Cornelius Nick Sykes wrote: > Hi all, just read the Victorian forecast for Saturday, sounding pretty > > interesting, does anyone think there is a chance of severe > thunderstorms im > Melbourne Saturday. > > BUREAU OF METEOROLOGY > VICTORIAN REGIONAL OFFICE > Issued at 1620 on Thursday the 15th of October 1998 > > Warnings > Nil. > > Victoria > A high pressure system will drift across Victoria overnight to lie > east of > the > state later on Friday. After a fairly cold night with fog patches, > Friday > will > be fine and generally sunny. Warmer northerly winds will develop in > the west > but > light winds and coastal seabreezes will prevail in central and eastern > > parts. > UV INDEX: Friday 7 [Very High] > > Saturday will be warm to very warm with strengthening northerly winds > ahead > of > an approaching cold front. The front will reach the west in the > afternoon > then > extend eastwards in the evening bringing cooler gusty west to > southwest > winds, > patchy rain and local thunder. > > The cold front will move through eastern Victoria on Sunday and there > will > be > some rain in all districts. Winds will be cool moderate to fresh > westerly. > > West to southwesterly winds will continue on Monday as another cold > front > moves > through Victoria and there will be scattered showers, mainly over > southern > and > mountain districts. > > Melbourne > > Tonight and Friday > Fine. A mainly sunny day with light wind, tending northerly, and > afternoon > sea > breezes. > > Min 8 Max 22 > > Saturday > Late change with thundery showers. Min 13 Max 29 > > Sunday > Rain at times. Min 15 Max 18 > > Monday > Few showers. Min 10 Max 16 > > Port Phillip Bay and Western Port > > Tonight and Friday > Southerly wind at about 10 knots becoming variable at 5 knots > overnight. > Wind > tending northerly tomorrow to 10 knots with afternoon seabreezes of > similar > strength. Waves to about half a metre. > > Saturday > Strengthening northerly wind ahead a late gusty west to southwest > change. > > Sunday > Moderate to fresh west to southwest wind. > > Monday > Moderate to fresh west to southwest wind. > > Headline Melbourne: Fine. Mainly sunny. > Headline Victoria: Fine but for local morning fog. Cold night. Mild > to warm > > ------- > -------------------------------------------------------------------- > ---- > Return to: Met Net (Home page) Help Search this site Send:Feedback > � Copyright Commonwealth of Australia 1998, Bureau of Meteorology. > Users of these Web pages are deemed to have read and accepted the > conditions > described in the copyright declaration. -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 07:10:53 -0400 From: David Hart To: aussie-weather at world.std.com Subject: aussie-weather: returned messages Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com I got messages that a couple of postings on the list bounced because of their size. There is an upward limit on the size of a message so that among other things we dont get mail-bombed. For large graphics its ususaly better to put them on the web somewhere, and then point to the URL on the list. -- On Thu, 15 Oct 1998 aussie-weather-approval at world.std.com wrote: > > Date: Thu, 15 Oct 1998 05:04:54 -0400 (EDT) > From: aussie-weather-approval at world.std.com > To: aussie-weather-approval at world.std.com > Subject: BOUNCE aussie-weather at world.std.com: Message too long (>40000 > chars) > > >From owner-aussie-weather Thu Oct 15 05:04:30 1998 > Return-Path: > Received: from world.std.com by europe.std.com (8.7.6/BZS-8-1.0) > id FAA13349; Thu, 15 Oct 1998 05:04:30 -0400 (EDT) > Received: from fep2.mail.ozemail.net by world.std.com (TheWorld/Spike-2.0) > id AA23065; Thu, 15 Oct 1998 05:03:02 -0400 > Received: from ozemail.com.au (slpen6p11.ozemail.com.au [203.108.160.155]) by > fep2.mail.ozemail.net (8.9.0/8.6.12) with ESMTP id TAA21220 for > ; Thu, 15 Oct 1998 19:02:05 +1000 (EST) > Message-Id: <3625B727.7F2DB695 at ozemail.com.au> > Date: Thu, 15 Oct 1998 18:49:44 +1000 > From: Matthew Piper > X-Mailer: Mozilla 4.5b2 [en] (Win95; I) > X-Accept-Language: en > Mime-Version: 1.0 > To: aussie-weather at world.std.com > Subject: Brisbane Webcam Images > Content-Type: multipart/mixed; > boundary="------------7732C5EBF82B71492F4542F6" [snip] On Thu, 15 Oct 1998 aussie-weather-approval at world.std.com wrote: > > Date: Thu, 15 Oct 1998 06:52:43 -0400 (EDT) > From: aussie-weather-approval at world.std.com > To: aussie-weather-approval at world.std.com > Subject: BOUNCE aussie-weather at world.std.com: Message too long (>40000 > chars) > > >From owner-aussie-weather Thu Oct 15 06:52:06 1998 > Return-Path: > Received: from world.std.com by europe.std.com (8.7.6/BZS-8-1.0) > id GAA04263; Thu, 15 Oct 1998 06:51:44 -0400 (EDT) > Received: from fep6.mail.ozemail.net by world.std.com (TheWorld/Spike-2.0) > id AA02582; Thu, 15 Oct 1998 06:48:48 -0400 > Received: from ozemail.com.au (slpen4p31.ozemail.com.au [203.108.160.111]) by > fep6.mail.ozemail.net (8.9.0/8.6.12) with ESMTP id UAA17079 for > ; Thu, 15 Oct 1998 20:48:19 +1000 (EST) > Message-Id: <3625D2C2.BAE295E4 at ozemail.com.au> > Date: Thu, 15 Oct 1998 20:47:30 +1000 > From: Matthew Piper > X-Mailer: Mozilla 4.5b2 [en] (Win95; I) > X-Accept-Language: en > Mime-Version: 1.0 > To: aussie-weather at world.std.com > Subject: Brisbane Webcam Images > Content-Type: multipart/mixed; > boundary="------------05E71F92789074B7D989BE9E" > > This is a multi-part message in MIME format. > --------------05E71F92789074B7D989BE9E > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > > Here are some of the images that I obtained from the Brisbane Webcam on > Tuesday. > > Matthew > > --------------05E71F92789074B7D989BE9E > Content-Type: image/jpeg; > name="test13.jpg" > Content-Transfer-Encoding: base64 > Content-Disposition: inline; > filename="test13.jpg" > > David Hart dhart at world.std.com -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 23:37:36 +1000 (EST) From: Paul Graham To: Aussie Weather Subject: aussie-weather: RE: Brisbane Supercell... Reply-Receipt: pgraham1 at extro.ucc.su.oz.au Reply-Read: pgraham1 at mail.usyd.edu.au Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com I thought it was interesting that it (the Brisbane storm), and a couple of other storms seemed to develop bow echoes as they approached the coast and they also changed direction slightly at this point. Possibly an interaction with the sea-breeze front aided the development of a mesocyclone - if you look on the Brisbane sounding, you will notice wind barbs on the right hand side. In the lower levels of the atmosphere, the wind significantly backs around from the north to become a westerly at higher levels as you would expect. Backing (or sometimes veering) is a significant factor in the formation of mesocyclones (as well as shear). I have a feeling that some similar sort of interaction may have occured with the Sydney, January, 21st, 1991, supercell since it very rapidly intensified as it approached the coast. These coastal supercells are quite interesting... - Paul G. I just talked to a guy in the severe weather section at the Brisbane Weather Bureau and he confirmed that it was a supercell. He said the cell responsible that was heading towards Brisbane suddenly intensified just after 2pm when it hit the seabreeze front. Dozens of people he said noticed the rotating mesocyclone (I didn't because rain spoiled my view) and the amateur video showing the swirls of debris was probably a 'young' tornado that wasn't able to reach full strength. He seemed hesitant to call it a tornado. I told him it either was or it isn't. He half agreed to that! -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 23:21:50 +1000 (EST) From: Paul Graham To: aussie-weather at world.std.com Subject: Re: aussie-weather: (no subject) Reply-Receipt: pgraham1 at extro.ucc.su.oz.au Reply-Read: pgraham1 at mail.usyd.edu.au Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com CAPE (Convective Availabe Potential Energy) values are usually quite high (as you would expect) for severe storms. Often values are over 2000J per Kg. An index which is used as an indicator for storm type is the Bulk Richardson Number. This is an index derived from CAPE and wind Shear over a layer. BRN values of between 10 and 40 indicate the possibility of supercells while values over 30 indicate possible multicell storms. - Paul. On Thu, 15 Oct 1998 paulmoss at tpgi.com.au wrote: > lAURIER: Thanx for the info on the upper air diagrams. Excellent stuff. Makes it > alot clearer now. I will fire off questions as they come to mind and the 1st one > is: (for anybody to answer!) > > What sort of cape levels do you require for thunderstorms/sever e storms?? Is > there a general guide? > > Regards, Paul from Taree > -------------------------------------------------------------------------------------- Date: Thu, 15 Oct 1998 23:50:46 +1000 (EST) From: Paul Graham To: Aussie Weather Subject: aussie-weather: Interesting Address... Reply-Receipt: pgraham1 at extro.ucc.su.oz.au Reply-Read: pgraham1 at mail.usyd.edu.au Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Take a look at: http://www.bom.gov.au/bmrc/regn/expt/tornado/tornado.html
Document: 981015.htm
Updated: 20th October, 1998 |
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