X-Sender: johnstone at psyphw.psych.wisc.edu X-Mailer: QUALCOMM Windows Eudora Pro Version 4.1 Date: Fri, 12 May 2000 10:51:48 -0500 To: aussie-weather at world.std.com From: Tom Johnstone Subject: aus-wx: cold fronts and warm fronts Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com There's a question that's been bugging me for a while now. Ever since living in Europe, and now in the USA, I've noticed as many warm fronts as cold fronts marked on weather maps. Yet in Australia, I can't remember ever having seen a warm front marked (admitedly my experience there is limited mostly to WA, but I also lived for a while in SA and Vic). Is this because warm fronts are not a regular part of Australia's weather, or does it reflect a difference in the way the BOM in Australia makes weather maps? The question is more than just curiosity for me. I've noticed that some of the most interesting weather events, both in Europe and USA, occur when a warm front and a cold front "collide" or converge in a small area. Of course, compared with southern WA, where the weather only really seems to come from one direction - the SW, Europe and the USA often have fronts coming from different directions, which sets up the possibility of such convergence. But doesn't NSW have similar converging weather patterns? Cheers, Tom Johnstone Tom Johnstone Psychology Department University of Wisconsin-Madison johnstone at psyphw.psych.wisc.edu +1 608 263 4517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ X-Originating-IP: [203.29.156.6] From: "T Middleton" To: aussie-weather at world.std.com Subject: Re: aus-wx: Joseph Banks see watrespouts off SE Australian coast - April 1770 Date: Sat, 13 May 2000 06:56:27 EST Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com interesting stuff Michael. >From: "Michael Thompson" >Reply-To: aussie-weather at world.std.com >To: >Subject: aus-wx: Joseph Banks see watrespouts off SE Australian coast - >April 1770 >Date: Fri, 12 May 2000 18:01:35 +1000 > >Another extract from a historic journal. This one about 2 days after >sighting the Aust' coast, must be around Eden at a guess. > > > > > We were now sailing along shore 5 or 6 Leagues from it, with a brisk >breeze of > > wind and cloudy unsettled weather, when we were calld upon deck to see >three > > water spouts, which at the same time made their appearance in different >places > > but all between us and the land. Two which were very distant soon >disapeard but > > the third which was about a League from us lasted full a quarter of an >hour. It > > was a column which appeard to be of about the thickness of a mast or a >midling > > tree, and reachd down from a smoak colourd cloud about two thirds of the >way to > > the surface of the sea; under it the sea appeard to be much troubled for >a > > considerable space and from the whole of that space arose a dark colourd >thick > > mist which reachd to the bottom of the pipe. When it was at its greatest > > distance from the water the pipe itself was perfectly transparent and >much > > resembled a tube of glass or a Column of water, if such a thing could be >supposd > > to be suspended in the air; it very frequently contracted and dilated, >lenghned > > and sho > > rtned itself and that by very quick motions; it very seldom remaind in a > > perpendicular direction but Generaly inclind either one way or the other >in a > > curve as a light body acted upon by wind is observd to do. During the >whole time > > that it lasted smaler ones seemd to attempt to form in its >neighbourhood; >at > > last one did about as thick as a rope close by it and became longer than >the old > > one which at that time was in its shortest state; upon this they Joind >together > > in an instant and gradualy contracting into the Cloud disapeard. > > > > > > > > > > > > > > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com > with "unsubscribe aussie-weather your_email_address" in the body of your > message. > -----------------------jacob at iinet.net.au------------------------------ ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ X-Originating-IP: [203.29.156.6] From: "T Middleton" To: aussie-weather at world.std.com Subject: aus-wx: report finally up Date: Sat, 13 May 2000 07:38:22 EST Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Well I've finally been able to get the waterspout photos and report up from April 20. It can be found at my new URL http://www4.tpgi.com.au/users/bigman/ PS.I was never really able to see the top of the cell properly but at best(and judging by the rest of the weather that morning)it would've been just a coastal congestus.and it was a rather small one at that. LATER..... tm ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ X-Sender: jdeguara at pop.ihug.com.au X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.2 Date: Sat, 13 May 2000 08:46:35 +1000 To: aussie-weather at world.std.com From: Jimmy Deguara Subject: Re: aus-wx: cold fronts and warm fronts Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Tom, I think since Australia has a larger mass of ocean to its south and also is situated further north that the mid-latitude low belts which would contain the warm fronts on the southern part of the low. So I think it is a combination of both. I recall in August 1998, a low pressure system moved onshore through Sydney and produced a storm surge. What I was interested on this day was the thunderstorms and cold conditions preceded the "eye" and almost a perfect one, and then was followed by SE milder air. I would say that this would have been something like a warm front or perhaps the warm core of the low centre. You could stand outside in shorts at night in August!!! I recall that I may have seen an occluded front on the southern part of this low the previous 24 hours but I am not going to bet on it. Jimmy Deguara At 10:51 12/05/00 -0500, you wrote: >There's a question that's been bugging me for a while now. Ever since >living in Europe, and now in the USA, I've noticed as many warm fronts as >cold fronts marked on weather maps. Yet in Australia, I can't remember ever >having seen a warm front marked (admitedly my experience there is limited >mostly to WA, but I also lived for a while in SA and Vic). Is this because >warm fronts are not a regular part of Australia's weather, or does it >reflect a difference in the way the BOM in Australia makes weather maps? > >The question is more than just curiosity for me. I've noticed that some of >the most interesting weather events, both in Europe and USA, occur when a >warm front and a cold front "collide" or converge in a small area. Of >course, compared with southern WA, where the weather only really seems to >come from one direction - the SW, Europe and the USA often have fronts >coming from different directions, which sets up the possibility of such >convergence. But doesn't NSW have similar converging weather patterns? > >Cheers, >Tom Johnstone >Tom Johnstone >Psychology Department >University of Wisconsin-Madison >johnstone at psyphw.psych.wisc.edu >+1 608 263 4517 > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com > with "unsubscribe aussie-weather your_email_address" in the body of your > message. > -----------------------jacob at iinet.net.au------------------------------ ---------------------------------------------------------------------------- --------------- Jimmy Deguara from Schofields, Sydney President of Australian Severe Weather Association Inc. (ASWA) http://severeweather.asn.au e-mail: jdeguara at ihug.com.au homepage with Michael Bath note new URL http://australiasevereweather.com/ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ X-Sender: paisley at mail.cobweb.com.au Date: Sat, 13 May 2000 08:29:23 +0930 To: aussie-weather at world.std.com From: Phil Bagust Subject: Re: aus-wx: cold fronts and warm fronts Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com >There's a question that's been bugging me for a while now. Ever since >living in Europe, and now in the USA, I've noticed as many warm fronts as >cold fronts marked on weather maps. Yet in Australia, I can't remember ever >having seen a warm front marked (admitedly my experience there is limited >mostly to WA, but I also lived for a while in SA and Vic). Is this because >warm fronts are not a regular part of Australia's weather, or does it >reflect a difference in the way the BOM in Australia makes weather maps? I'll have a go at this, although there will be many others who will do better. 1] yes, there are warm fronts in the southern hemisphere, but continental Australia is just too far north to be regularly affected by them [I actually have a few examples of them on MSL charts in my collection]. I remember when I was on holiday in Tasmania [further south] the MSL map in the Hobart Mercury stretched down past 50 south and regularly included warm fronts. 2] yes, there are warm fronts in the southern hemisphere, but the BoM simplifies the maps for public consumption. For instance a stationary front will not be shown of Aussie maps, nor will a warm front-like feature that doesn't produce significant weather [not sure about this - comments anyone??] 3] there are some differences between cyclogenesis in the southern ocean compared to the north, presumably because of the great ocean area. Would someone else like to comment on 'instant occlusions' and other southern specialties?? Hope this starts the ball rolling..... Phil 'Paisley' Bagust paisley at cobweb.com.au http://www.chariot.net.au/~paisley2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ From: "Wilson" Organization: Griffith University To: aussie-weather at world.std.com Date: Sat, 13 May 2000 09:30:55 +1000 Subject: aus-wx: What is that????? X-mailer: Pegasus Mail for Win32 (v3.12b) Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi all, I would like to know what is this effect?? is that the radar problem or it is something else??? See attachment !! There is a big blue circle around Charleville , I cannot believe if it is true or not.... Wilson The following section of this message contains a file attachment prepared for transmission using the Internet MIME message format. If you are using Pegasus Mail, or any another MIME-compliant system, you should be able to save it or view it from within your mailer. If you cannot, please ask your system administrator for assistance. ---- File information ----------- File: IDR531.gif Date: 13 May 2000, 9:27 Size: 18196 bytes. Type: GIF-image Attachment Converted: "c:\eudora\attach\IDR531.gif" Date: Fri, 12 May 2000 20:24:22 -0400 From: "Leslie R. Lemon" Subject: aus-wx: What is that????? To: "INTERNET:aussie-weather at world.std.com" X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id UAA21606 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com This is not real. It looks like a test signal to me. Les > Hi all, > > I would like to know what is this effect?? is that the radar problem or it is something else??? > > See attachment !! There is a big blue circle around Charleville , I cannot believe if it is true or not.... > > Wilson ************************ Leslie R. Lemon Radar, Severe Storms, & Research Meteorologist Tel. 816-373-3533, 816-213-3237 E-Mail: lrlemon at compuserve.com +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ Date: Fri, 12 May 2000 21:16:53 -0400 From: "Leslie R. Lemon" Subject: aus-wx: cold fronts and warm fronts To: "INTERNET:aussie-weather at world.std.com" X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id VAA29985 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Tom Johnstone wrote: > There's a question that's been bugging me for a while now. Ever since > living in Europe, and now in the USA, I've noticed as many warm fronts as > cold fronts marked on weather maps. Yet in Australia, I can't remember ever > having seen a warm front marked (admittedly my experience there is limited > mostly to WA, but I also lived for a while in SA and Vic). Is this because > warm fronts are not a regular part of Australia's weather, or does it > reflect a difference in the way the BOM in Australia makes weather maps? > I find a big difference in the way the BoM analyze surface charts which I have mentioned before but will outline here again. This is completely apart from your warm front question. My question deals with their principals of surface map analysis which I want to understand. The principals for surface frontal analysis I have been taught (see the web site below) and used extensively emphasize the use of wind shifts, thermodynamic changes, and pressure troughs, etc. for the identification of fronts. Fronts are defined to be the leading edge of an airmass change. Air pressures behind a cold front, for example, rise, temperatures cool and winds shift ushering in a high pressure system characterized by general homogeneity and therefore the lack of any strong gradients in the measurable surface quantities and therefore the absence of fronts. one of the most prominent characteristics of the front is the the distinct pressure trough with the front. That, in fact, is why the wind direction and speed change at the front. With this in mind, I have been attempting to understand the BoM surface map analyses. Frequently, as with the latest surface analysis, I see fronts extending deep into high pressure regions without the existence of the typical pressure trough (except perhaps some slight one introduced by the analyst). Moreover, the pressure troughs where there are almost certainly wind shifts and marked thermodynamic changes with rising pressures to the rear are largely ignored for the placement of surface fronts or boundaries of any other kind. Then I also saw a variation of this theme. In that situation I saw an analysis in which a "cold front" was placed within a strong pressure gradient but parallel to the isobars. The result was that "behind" the "cold" front pressures fell rapidly in such a manner that surface winds blew largely parallel to the front but almost certainly flowed with a component through this "front" from ahead of, to the rear of the "advancing cold front". In other words, would there be an atmospheric discontinuity, a change in airmass with wind direction, temperature drop, and pressure change where the cold front was placed? I wondered if, because much of these analyses are over the ocean in data void areas, regions of satellite depicted cloud were being used for frontal placement. Could this be true? But if true, there would still seem to be a disparity between cloudiness and the weather and the associated surface chart. I guess my question is obvious. What principals are used instead of those I have outlined above and referenced below? Are fronts assumed or defined to be something other than airmass changes? Can anyone direct me to texts that are used that define and explain these analyses techniques? Please find the principals I have explained and more, outlined here: > The question is more than just curiosity for me. I've noticed that some of > the most interesting weather events, both in Europe and USA, occur when a > warm front and a cold front "collide" or converge in a small area. Of > course, compared with southern WA, where the weather only really seems to > come from one direction - the SW, Europe and the USA often have fronts > coming from different directions, which sets up the possibility of such > convergence. But doesn't NSW have similar converging weather patterns? Here you are speaking of the "occlusion" process. The occlusion of a surface low occurs at or near the point of maximum intensity of the surface cyclone. When that occurs the cold front overtakes the warm front. Les ************************ Leslie R. Lemon Radar, Severe Storms, & Research Meteorologist Tel. 816-373-3533, 816-213-3237 E-Mail: lrlemon at compuserve.com +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ From: "Michael Thompson" To: Subject: Re: aus-wx: report finally up Date: Sat, 13 May 2000 15:45:54 +1000 X-Mailer: Microsoft Outlook Express 5.00.2014.211 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Excellent pics, no doubt about these. Michael ----- Original Message ----- From: T Middleton To: Sent: Saturday, 13 May 2000 22:38 Subject: aus-wx: report finally up > Well I've finally been able to get the waterspout photos and report up from > April 20. > It can be found at my new URL > http://www4.tpgi.com.au/users/bigman/ > > PS.I was never really able to see the top of the cell properly but at > best(and judging by the rest of the weather that morning)it would've been > just a coastal congestus.and it was a rather small one at that. > > LATER..... tm > ________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com > with "unsubscribe aussie-weather your_email_address" in the body of your > message. > -----------------------jacob at iinet.net.au------------------------------ > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ From: "Michael Thompson" To: Subject: Re: aus-wx: cold fronts and warm fronts Date: Sat, 13 May 2000 15:40:20 +1000 X-Mailer: Microsoft Outlook Express 5.00.2014.211 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com The problem lack of landmass at high latitudes. You see them occasionally over the southern ocean. If the Australian landmass extended further below 40'S they would be a regular feature. Michael > There's a question that's been bugging me for a while now. Ever since > living in Europe, and now in the USA, I've noticed as many warm fronts as > cold fronts marked on weather maps. Yet in Australia, I can't remember ever > having seen a warm front marked (admitedly my experience there is limited > mostly to WA, but I also lived for a while in SA and Vic). Is this because > warm fronts are not a regular part of Australia's weather, or does it > reflect a difference in the way the BOM in Australia makes weather maps? > > The question is more than just curiosity for me. I've noticed that some of > the most interesting weather events, both in Europe and USA, occur when a > warm front and a cold front "collide" or converge in a small area. Of > course, compared with southern WA, where the weather only really seems to > come from one direction - the SW, Europe and the USA often have fronts > coming from different directions, which sets up the possibility of such > convergence. But doesn't NSW have similar converging weather patterns? > > Cheers, > Tom Johnstone > Tom Johnstone > Psychology Department > University of Wisconsin-Madison > johnstone at psyphw.psych.wisc.edu > +1 608 263 4517 > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com > with "unsubscribe aussie-weather your_email_address" in the body of your > message. > -----------------------jacob at iinet.net.au------------------------------ > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ From: "Les Crossan" To: Subject: Re: aus-wx: What is that????? Date: Sat, 13 May 2000 08:26:58 +0100 Organization: Cosmic EuroCon - note all times are always GMT X-Mailer: Microsoft Outlook Express 5.00.2615.200 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com ----- Original Message ----- From: Wilson To: Sent: Saturday, May 13, 2000 12:30 AM Subject: aus-wx: What is that????? > Hi all, > > I would like to know what is this effect That effect is "broken radar - call the BoM, quick" (: Les (UK) ------------------------------------------------------ Les Crossan Wallsend, Tyne & Wear, UK 54-59N 01-30W UK Storm Chaser / Severe Weather Enthusiast http://www.uksevereweather.org.uk Melbourne Storm Chasers (MSC) - Victoria, AUS http://www.rubix.net.au/~cadence/ Australian Severe Weather Association (ASWA) - AUS http://www.severeweather.asn.au/ Tornado and Storm Research Organisation (TORRO) - UK Thunderstorm Census Organisation (TCO) - UK http://www.torro.org.uk/ Email: les.crossan at virgin.net ICQ: 17296776 ------------------------------------------------------ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ From: "Les Crossan" To: Subject: Re: aus-wx: cold fronts and warm fronts Date: Sat, 13 May 2000 09:41:12 +0100 Organization: Cosmic EuroCon - note all times are always GMT X-Mailer: Microsoft Outlook Express 5.00.2615.200 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com ----- Original Message ----- From: Leslie R. Lemon To: Sent: Saturday, May 13, 2000 2:16 AM Subject: aus-wx: cold fronts and warm fronts > > the most interesting weather events, both in Europe and USA, occur when a > > warm front and a cold front "collide" or converge in a small area. "Occluded fronts" happen when the cold front overtakes the warm front, lifting the warm air above the surface - it is generally regarded as the last stage in the depressions' lifecycle as the fuel for the low is cut off. The major frontal action occurs in the UK and Europe in rearward sloping anacoldfronts in winter, these show on pressure charts as a shift / kink in the isobars, mainly from SW-NW. These look like thin but intense lines on radar with a sharp back edge, similar to line squalls, and can become very intense (and tornadic) after traversing a landmass as friction affects the surface air, indeed these are the main source of tornadoes in the UK! Occlusions fire up in summertime when they can become thundery after traversing a large warm landmass i.e. they are fairly innocuous in Bristol but spawning golfball hail and tornadoes in Lincoln. The Netherlands (Holland) gets its fair share of action from these frontal systems (including supercells); something to do with the large flat landmass as does central France in summer when MCS cause torrential rain over EuroDisney... My 0.01$ worth. Les ------------------------------------------------------ Les Crossan Wallsend, Tyne & Wear, UK 54-59N 01-30W UK Storm Chaser / Severe Weather Enthusiast http://www.uksevereweather.org.uk Melbourne Storm Chasers (MSC) - Victoria, AUS http://www.rubix.net.au/~cadence/ Australian Severe Weather Association (ASWA) - AUS http://www.severeweather.asn.au/ Tornado and Storm Research Organisation (TORRO) - UK Thunderstorm Census Organisation (TCO) - UK http://www.torro.org.uk/ Email: les.crossan at virgin.net ICQ: 17296776 ------------------------------------------------------ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ X-Originating-IP: [203.22.16.30] From: "Rod Aikman" To: aussie-weather at world.std.com Subject: Re: aus-wx: cold fronts and warm fronts Date: Sat, 13 May 2000 21:50:10 EST Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com This warm front "problem" is one I believe southern hemisphere meteorologists have been grappling with for many years. It is true that warm fronts are often analysed on surface charts in latitudes 40 deg. plus; but even these are mostly short lived, insignificant events which seldom persist for more than 24 hours or so. Rarely does a cold front occlude with them as often they are analysed in a north-west, south-east orientation from the cyclonic centre. When warm fronts do occur over Victoria as an example, they usually follow a substantial cold outbreak over southern Australia, followed by a weak and rapidly moving ridge, then by another low pressure trough following rapidly behind this. The warm southward flowing airmass then rises gradually over the cold air left in the wake of the previous cold outbreak and forms a temperature/moisture discontinuity at the surface. My two cents worth Rod Aikman 42 Panton St Golden Square, Bendigo, Vic There's a question that's been bugging me for a while now. Ever since living in Europe, and now in the USA, I've noticed as many warm fronts as cold fronts marked on weather maps. Yet in Australia, I can't remember ever having seen a warm front marked (admitedly my experience there is limited mostly to WA, but I also lived for a while in SA and Vic). Is this because warm fronts are not a regular part of Australia's weather, or does it reflect a difference in the way the BOM in Australia makes weather maps? The question is more than just curiosity for me. I've noticed that some of the most interesting weather events, both in Europe and USA, occur when a warm front and a cold front "collide" or converge in a small area. Of course, compared with southern WA, where the weather only really seems to come from one direction - the SW, Europe and the USA often have fronts coming from different directions, which sets up the possibility of such convergence. But doesn't NSW have similar converging weather patterns? Cheers, Tom Johnstone Tom Johnstone Psychology Department University of Wisconsin-Madison johnstone at psyphw.psych.wisc.edu +1 608 263 4517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------ ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from aussie-weather send e-mail to:majordomo at world.std.com with "unsubscribe aussie-weather your_email_address" in the body of your message. -----------------------jacob at iinet.net.au------------------------------