Date: Sun, 14 May 2000 12:38:06 -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 MAA16905 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Les C. wrote: > Perhaps not in Vic but a warm front event at 55N can bring all sorts of > interesting things with it, things like snow, glazed ice and continuous > heavy rain. Also temperatures can rise by 10C or so in the middle of winter! > Atlantic warm fronts can survive for a loooong time until the low is > absorbed, dissapates or occludes. > Yes, warm fronts are common, as are extra-tropical cyclones on polar or maritime fronts. Atmospheric physics remain the same around the globe. > A classic Atlantic low pressure system (at sea level) has the warm front > lying from SE to the centre of the low with winds backing from NW to SW in > front of it, veering slowly W (or remaining SW in some cases usually > depicted on a chart as straight isobars) during and after it and rapidly > veering NW after the cold front. The occlusion starts at the centre and > works out to the edge of the low, sometimes the occlusion shows a hook in > the centre. Once the occlusion is complete the low generally dissapates and > dissapears from the chart. Sometimes a new low pressure system forms further > down the cold front and absorbs the old one into its circulation. I don't > know much about the upper air dynamics of LP systems but generally the > midlevel jet (500mb or so) is above and parallel to the cold front. > I have written a paper a couple of years ago concerning the similarities of the synoptic ETC (extratropical or extra-tropical cyclone) and the mesocyclone. The reason I call attention to that paper here is because it shows the ETC and the major "conveyer belts" of flow from Browning and others. Yes, the same UK scientist who named and documented the structure of the supercell thunderstorm has written much about the ETC and the conveyer belt perspective!! (I also think you might like the paper from the standpoint of the similarities of the ETC and mesocyclone and tornadogenesis.) Because attachments wont work here, I will be glad to e-mail the paper to anyone wishing to read it. I differ some from LC's description here such as the extension of the warm front into a high, etc., but that is not really important. Rather, please see these URLs....at the risk of overkill! LOL In addition to these listed URLs, you can also use the last one, the index, to read about airmasses (and much more) which deal with earlier posts of mine. Midlatitude Cyclones cold front structure in the vertical. cold front structure in the horizontal. cold front and the ETC. animated cold front and precip. ETC and cold front association. cold front and wind shift across it. Fronts and the dryline. The occlusion process and fronts. The stationary front. The warm front. cyclones and the associated warm front. The warm front and associated precip. Animated. The Index with many other relevant subjects such as airmases, etc. 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------------------------------ Date: Mon, 15 May 2000 03:14:41 -0700 From: Lindsay X-Mailer: Mozilla 3.0 (Win16; I) To: aussie-weather at world.std.com Subject: Re: aus-wx: Strong Winds Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Thanks Laurier, I must be a reasonably good guess as I told my partner I reckoned it was close to a 100 kilometres at midday. Our outdoor furniture starts to blow over at around that speed as its protected behind trees from lesser winds. Yes, the windchill was nasty. I drove out to a lookout just after Mt Vic township and looked across to Mt Trickett. Low-ish cloud and nasty looking out there at midday. Anyone got any tables or links for windchill? Or indeed how its calculated? I've got a basic chart but am looking for more. Cheers, Lindsay Pearce Laurier Williams wrote: > > Lindsay, highest gust reported at Mt Boyce during the day was 53 knots > or 98km/h at midday. Currently (11pm) it's a mere 31km/h average, > gusting to 52, temp 4.8. The electric blanket, turned to high, awaits. > > Laurier > > On Sun, 14 May 2000 13:34:05 +1000, Matt Smith > wrote: > > >Hi Lindsay > > > >http://www.bom.gov.au/olympic/products/IDN60013.shtml > > > >Look at that page for latest obs around sydney, Mount Boyce AWS is also > >there, currently it shows a Westerly at 48km/h and Wollongong Airport AWS > >has 56km/h. > > > >Also check Lauriers page of noteworthy weather obs for around Australia, > >http://ausweather.simplenet.com/current_severe.html > > > >I havent checked it but it should show some info on wind gusts for your area. > > > >Matt Smith > >http://www.sydneystormchasers.com > >http://www.severeweather.asn.au > >>Strong winds in Upper Blue Mountains. Can't get into the AWS stuff on > >>the ASWA site but its howling up here. > >> > >>Currently 9.5 degrees at 12pm > >> > >>Lindsay Pearce > >> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >> 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------------------------------ > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > 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------------------------------ X-Originating-IP: [203.29.156.6] From: "T Middleton" To: aussie-weather at world.std.com Subject: Re: aus-wx: Strong Winds Date: Mon, 15 May 2000 07:14:27 EST Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com weather calculator ; http://www.srh.noaa.gov/elp/wxcalc/wxcalc.html >From: Lindsay >Reply-To: aussie-weather at world.std.com >To: aussie-weather at world.std.com >Subject: Re: aus-wx: Strong Winds >Date: Mon, 15 May 2000 03:14:41 -0700 > >Thanks Laurier, > >I must be a reasonably good guess as I told my partner I reckoned it was >close to a 100 kilometres at midday. Our outdoor furniture starts to >blow over at around that speed as its protected behind trees from lesser >winds. > >Yes, the windchill was nasty. I drove out to a lookout just after Mt Vic >township and looked across to Mt Trickett. Low-ish cloud and nasty >looking out there at midday. > >Anyone got any tables or links for windchill? Or indeed how its >calculated? > >I've got a basic chart but am looking for more. > > >Cheers, > > >Lindsay Pearce > > >Laurier Williams wrote: > > > > Lindsay, highest gust reported at Mt Boyce during the day was 53 knots > > or 98km/h at midday. Currently (11pm) it's a mere 31km/h average, > > gusting to 52, temp 4.8. The electric blanket, turned to high, awaits. > > > > Laurier > > > > On Sun, 14 May 2000 13:34:05 +1000, Matt Smith > > wrote: > > > > >Hi Lindsay > > > > > > > >http://www.bom.gov.au/olympic/products/IDN60013.shtml > > > > > >Look at that page for latest obs around sydney, Mount Boyce AWS is also > > >there, currently it shows a Westerly at 48km/h and Wollongong Airport >AWS > > >has 56km/h. > > > > > >Also check Lauriers page of noteworthy weather obs for around >Australia, > > >http://ausweather.simplenet.com/current_severe.html > > > > > >I havent checked it but it should show some info on wind gusts for your >area. > > > > > >Matt Smith > > >http://www.sydneystormchasers.com > > >http://www.severeweather.asn.au > > >>Strong winds in Upper Blue Mountains. Can't get into the AWS stuff on > > >>the ASWA site but its howling up here. > > >> > > >>Currently 9.5 degrees at 12pm > > >> > > >>Lindsay Pearce > > >> >+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > >> 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------------------------------ > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > 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------------------------------ ________________________________________________________________________ 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------------------------------ From: "Les Crossan" To: Subject: Re: aus-wx: What is that????? Date: Sun, 14 May 2000 21:57:59 +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?? is that the radar problem or it is something else I was chatting to my brother on IRC about this - he's an electronics officer with Peninsular & Orient (the cruise line). He's had some strange things with radar usually to do with tropospheric ducting and inversions so they've had things like "aircraft" travelling at 20000 miles an hour at sea level (satellites), ships on top of them and artefacts like that one in the attachment but more likely, he says, the radar's goosed. 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.NOSPAMcrossan at virgin.net (remove NOSPAM) 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: David Jones To: "Aussie Weather (E-mail)" Subject: aus-wx: Warm fronts.... Date: Mon, 15 May 2000 10:29:27 +1000 X-Mailer: Internet Mail Service (5.5.2650.21) Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Just my two bobs worth regarding warm fronts in the SH. >From my weather watching/experience, classical warm fronts are really pretty rare over Australia (and indeed much of the SH). The reasons being, We are just too far north. Warm fronts tend to occur at latitudes near or poleward of the attendant low. As most lows pass well south of Aus. so do their associated warm fronts. The mid/upper flow is just too zonal. In those instances where there is a well developed warm/cold discontinuity the translation speed of the entire (low/front) system usually substantially exceeds the relative motion of the warm/cold discontinuity about the associated low. So, in a relative sense you have a warm front. That is warm air displaces cold air as the front typically rotates clockwise around the low. However, in an absolute sense, the "warm" front is being advected (usually) rapidly towards the east and at a fixed location an observer never actually sees warm air replace cold. Over the southern ocean there is just not the temperature gradient to develop sharp warm fronts. In Victoria I can only recall seeing three significant warm fronts since 1987. From memory - in each case we had a large amplitude thermal trough (essentially a cold outbreak) cut-off, then under went substantial cyclogenesis near Victoria. The subsequent low was well removed from the mid latitude westerlies - slow moving. >From memory, the first occurred on the June 1989 long weekend. The Saturday was very cold and rainy. My max to 3pm was 10C. By morning, the temperature was 14C and the dewpoint about 11C. Possibly the most dramatic "warm front" feature I have seen occurred with the low which produced the severe flooding in Eastern Victoria around 24/6/1998 (285mm at Club Terrace). On the afternoon of the 23rd this system developed a quite remarkable "warm front" which rotated clockwise around the parent cut-off. Unfortunately observations are very sparse in this region, though the observations at Omeo (685m) and Gabo Island (15m) make an interesting comparison - though obviously biased by altitude. At 3pm Omeo had a temp of 1 and a dewpoint of 1 with snow. At the same time Gabo Island had a temp of 15 and a dewpoint of 15 with rain. I understand that the valleys around Omeo received upto 1m of snow in this event down to about 400-500ms. Cheers, DAJ Dr David Jones Climate Analysis Section National Climate Centre Bureau of Meteorology Fax : (+61 3) 9669 4678 GPO Box 1289K, Melbourne Ph (work): (+61 3) 9669 4861 Victoria 3001, Australia Ph (home): (+61 3) 9898 4425 email : D.Jones at bom.gov.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: Blair Trewin Subject: Re: aus-wx: Strong Winds To: aussie-weather at world.std.com Date: Mon, 15 May 2000 11:17:42 +1000 (EST) X-Mailer: ELM [version 2.5 PL2] Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com > > Strong winds in Upper Blue Mountains. Can't get into the AWS stuff on > the ASWA site but its howling up here. > > Currently 9.5 degrees at 12pm > > Lindsay Pearce I got to see this event in its full glory in the region where it appears to have been at its most intense, the coast of SE South Australia. I haven't, as yet, had the chance to check any observations from the region - the AWS in the area, Cape Jaffa, doesn't feature on the notable observations on Laurier's site for Friday night, but I don't know if that was because the winds weren't strong enough or because the station wasn't reporting for some reason (I suspect the latter). The winds were at their peak during Friday night and early Saturday morning, but were still near gale force on exposed coasts on Sunday morning. I would estimate the winds in Robe on Friday night at a mean of around 40 knots, with gusts into the 50s; this seems fairly consistent with Neptune Island, which peaked at 60. The rainfall was an interesting aspect of this system. There were long fine intervals, but the showers, when they occurred, were extremely heavy for this type of system (probably up around 30-50 mm/hr for brief periods). Typical daily falls seem to have been around 10mm, falling in half-a-dozen five-minute showers - although the observation network this weekend is pretty sparse (it's sparse at the best of times, especially north of Robe, and being a long weekend in SA a lot of rainfall stations won't report until Tuesday). I didn't observe any hail, thunder or funnel clouds :-( The high winds did have their advantages - caught outside on the sand dunes during one particularly heavy shower on Saturday afternoon, the rain was so horizontally driven that standing on the lee side of a bush was enough to stay almost totally dry, despite the lack of any cover overhead! Melbourne and Hobart both seem to have missed out almost completely. Melbourne is unlikely to see any significant rainfall for the next week and is therefore well on the way to yet another below-average month, despite the major rain event in the first week. The water levels in Melbourne's reservoirs actually went up this week - by 0.005%! Blair Trewin +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Blair Trewin Subject: Re: aus-wx: cold fronts and warm fronts To: aussie-weather at world.std.com Date: Mon, 15 May 2000 11:22:14 +1000 (EST) X-Mailer: ELM [version 2.5 PL2] 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?? > David Jones has already commented extensively on this so I won't repeat his comments, but rather make a couple of additions: 1. I'm not aware of any internal charts that do anything more in the way of frontal display than the publicly available ones do. 2. The way fronts have been analysed has changed quite a bit over the years; there are some particularly weird and wonderful examples from the early years of routine satellite coverage. I have seen charts from the late 1960's and early 1970's which have cold fronts analysed running west-east across Cape York Peninsula! Blair Trewin +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Sun, 14 May 2000 21:29:49 -0400 From: "Leslie R. Lemon" Subject: aus-wx: Warm fronts.... To: "INTERNET:aussie-weather at world.std.com" X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id VAA10424 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com David: > From my weather watching/experience, classical warm fronts are really pretty > rare over Australia (and indeed much of the SH). The reasons being, > > We are just too far north. Warm fronts tend to occur at latitudes near or > poleward of the attendant low. As most lows pass well south of Aus. so do > their associated warm fronts. much omitted Thanks, a very interesting post. Yes, if you are too far north, there will be far fewer warm fronts. That is too bad. It helps explain the limited number of tornadoes (lack of strong jets aloft, lack of deep layer shear, and the lack of mid-level cold, dry air with sufficient frequency overlaying moist unstable surface air. Further, it certainly argues against much snow at all....the surface low/cyclone must pass north of your location. I very much appreciate living here in the US. Last Thursday (I think) we had three supercells with great hook echoes all lined up west of us on the interstate that passes a couple of miles south of us. We ended up having a tornado six miles north of us. It was a great evening. Fortunately, there was only one fatality and ~ 220 homes severely damaged and the tornadoes, when over populated areas, were at their weakest. I will probably send some of the images to Jane to post when she can come up for air. Visit us when you can! Again, thanks for the very informative post! 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: "Lyle Pakula" To: Subject: Re: aus-wx: cold fronts and warm fronts Date: Mon, 15 May 2000 11:54:07 +1000 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 Hi Blair, > 2. The way fronts have been analysed has changed quite a bit over the > years; there are some particularly weird and wonderful examples from > the early years of routine satellite coverage. I have seen charts > from the late 1960's and early 1970's which have cold fronts > analysed running west-east across Cape York Peninsula! It's funny you should say that. In class the other day when we were doing front formation, our lecturer was talking about how the BOM is very conservative with their depiction of fronts. He sited cases where cold fronts had travelled up to trigger Monsoonal activity *across* the equator, wow! Cheers, Lyle +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Mon, 15 May 2000 11:48:31 +0930 To: aussie-weather at world.std.com From: Phil Bagust Subject: aus-wx: Re: Adelaide rain Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Absolutely belting down here in Adelaide. Well over 50mm in the last few days now. 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: Chris Nitsopoulos Date: Mon, 15 May 2000 14:00:42 +1000 To: aussie-weather , aussie-weather Cc: aussie-weather Subject: aus-wx: Tropical Cyclones User-Agent: IMP/PHP IMAP webmail program 2.2.0-pre10 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Guys and Gals I\'m Chris and I have recently joined the mailing list and am very grateful I did, as there are alrady a ton of interesting web sites on severe weather. But if I was to ask what would be the best site to look at which one would you all recommeend. Also I am fascinated by Tropical Meteorology and in particular Tropical Cyclones. I was wondering where can I find the best Tropical analysis charts as well as the #1 site on Tropical Cyclones. One last thing I was wondering was, Is anyone currently or have recently studied meteorology at Uni? +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Mon, 15 May 2000 13:39:59 +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 >> 2. The way fronts have been analysed has changed quite a bit over the >> years; there are some particularly weird and wonderful examples from >> the early years of routine satellite coverage. I have seen charts >> from the late 1960's and early 1970's which have cold fronts >> analysed running west-east across Cape York Peninsula! > >It's funny you should say that. In class the other day when we were doing >front formation, our lecturer was talking about how the BOM is very >conservative with their depiction of fronts. He sited cases where cold >fronts had travelled up to trigger Monsoonal activity *across* the equator, >wow! > >Cheers, >Lyle Here's a good example Lyle, We had a definite line of heavy showers through Adelaide this morning. 10mm fell in about 30 minutes. It was more than just 'stream showers' I feel. The back edge of this line was quite spectacular, although there was no glaciation. Was this feature shown on the MSL map? No! [although there was a suspicious widening of the isobars west of Tasmania indicating perhaps the development of a small low in the SW stream in that area??]. So, was this 'trough' just that, a kink in the isoabrs indicating some convergence but no real air mass change? Was it a front? Was it my imagination? ;) 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------------------------------ Date: Mon, 15 May 2000 00:36:39 -0400 From: "Leslie R. Lemon" Subject: Re: 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 AAA03537 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Blair Trewin wrote: > 1. I'm not aware of any internal charts that do anything more in the > way of frontal display than the publicly available ones do. > > 2. The way fronts have been analysed has changed quite a bit over the > years; there are some particularly weird and wonderful examples from > the early years of routine satellite coverage. I have seen charts > from the late 1960's and early 1970's which have cold fronts > analysed running west-east across Cape York Peninsula! Hi Blair Where is Cape York Peninsula? As you can see, my knowledge of Australian geography is not good. Thanks for this message. Because you are in the BoM, perhaps you are aware of their principals of map analysis and especially the placement of fronts, extra-tropical cyclones, the interpretation of pressure troughs and the difference between them and fronts, etc. Are you familiar with these principals or are you aware of a web site where I might find such? Thanks very much for your time and whatever help you can be. 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: Blair Trewin Subject: aus-wx: The first 'snow prediction' of the year... To: aussie-weather at world.std.com (Aussie Weather) Date: Mon, 15 May 2000 15:29:57 +1000 (EST) X-Mailer: ELM [version 2.5 PL2] Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com As sure a harbinger of May as the leaves falling off the tree outside my front door, the weekend saw the first public pronouncement of the prospects for the ski season by a spokescreature from a ski resort. You will not be surprised to learn that said person predicted that signs look good for the coming season. In the words of Mandy Rice-Davies, 'he would say that, wouldn't he?'. Blair Trewin +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: David Jones To: "Aussie Weather (E-mail)" Subject: aus-wx: front.. Date: Mon, 15 May 2000 17:02:37 +1000 X-Mailer: Internet Mail Service (5.5.2650.21) Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Phil, The 18Z chart did infact have a decaying front marked from (about) Gabo Island, through Mt Gambier, then to Port Lincoln. Bt 21Z this had gone and been replaced by a weak trough line on the analysis... I guess it all comes down to semantics, and how strong a discontinuity has to be to be called a front. Here in Melbourne, the "front" appeared as a quite coherent line of showers moving up from Bass Strait which managed to die in the 50km trip from the heads to the city.... :-( Cheers, David. Dr David Jones Climate Analysis Section National Climate Centre Bureau of Meteorology Fax : (+61 3) 9669 4678 GPO Box 1289K, Melbourne Ph (work): (+61 3) 9669 4861 Victoria 3001, Australia Ph (home): (+61 3) 9898 4425 email : D.Jones at bom.gov.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: Warm fronts.... Date: Mon, 15 May 2000 20:01:07 +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 Don't worry many of us intend too, there is just one complication, the Australian Dollar is very sick. In the 1970's it used to be close to value with the US dollar, then in the 1980's with deregulation it plummeted, but usually hung on the same value as the Canadian Dollar, but the last three months have seen it go into territory occupied by Asian currencies. Michael > > Visit us when you can! Again, thanks for the very informative post! > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Mon, 15 May 2000 20:03:23 +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 Mmmmmm! usually a strong front associated with a massive high is what kills the monsoon, establishing the SE trades, and the front hardly ever makes the tropic of Capricorn. My amateur opinion anyway. Michael > It's funny you should say that. In class the other day when we were doing > front formation, our lecturer was talking about how the BOM is very > conservative with their depiction of fronts. He sited cases where cold > fronts had travelled up to trigger Monsoonal activity *across* the equator, > wow! > > Cheers, > Lyle > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > 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------------------------------ Date: Mon, 15 May 2000 20:55:52 +1000 From: Anthony Cornelius X-Mailer: Mozilla 4.72 [en] (Win98; I) X-Accept-Language: en To: aussie-weather at world.std.com 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 Michael, Cold fronts are thought to be one the processes that trigger the monsoonal onset. For example, the monsoon generally requires the presence of the Pilbara and Cloncury lows to be present. This draws in a moist inflow from the tropical oceans. However, it then presents a sharp moisture discontinuity over the northern Australia region (over land), as you have tropical maritime air, and tropical continental air beside each other. However, there's no real disturbance besides the two heat lows/troughs - and while the atmosphere is unstable to about 700mb, due the to nature of heat lows/troughs generally anti-cyclonic conditions occur above 700mb, thus adding subsidence to the area. So you have a quasi-state equilibrium over the area, and no real trigger to spark off convection. A cold front is thought to be one of three triggers that allow the monsoon to fully develop. It displaces the tropical continental air and since the heat trough is dependent on heat, moves northwards into the moist (unmixed) tropical maritime air. This adds further convergence to the air, and is thought to be a trigger. Convection then breaks out on the northern side of the trough. The other two methods are thought to be anticyclogenesis causing barotropic instability (it is sometimes associated with a cold front too, and is thought to have a similar effect...however increases horizontal wind shear in the E'lies). And the other method is considered to be an extension of a long wave trough. None the less...these methods (at least in my opinion), could also have a negative effect should they occur at the 'wrong' time, or have other systems associated with them. I'm curious about the cold fronts triggering monsoons on the other side of the equator though! This is most difficult to conceptualise... Michael Thompson wrote: > > Mmmmmm! usually a strong front associated with a massive high is what kills > the monsoon, establishing the SE trades, and the front hardly ever makes the > tropic of Capricorn. My amateur opinion anyway. > > Michael > > > It's funny you should say that. In class the other day when we were doing > > front formation, our lecturer was talking about how the BOM is very > > conservative with their depiction of fronts. He sited cases where cold > > fronts had travelled up to trigger Monsoonal activity *across* the > equator, > > wow! > > > > Cheers, > > Lyle > > > > > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > 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------------------------------ -- Anthony Cornelius Queensland Coordinator of the Australian Severe Weather Association (ASWA) (07) 3390 4812 14 Kinsella St Belmont, Brisbane QLD, 4153 Please report severe thunderstorms on our Queensland severe thunderstorm reporting line on (07) 3390 4218 or by going to our homepage at http://www.severeweather.asn.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: Mon, 15 May 2000 21:45:32 +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 Thanks Anthony, you learn something everyday and that was one thing I certainly never knew about ! You do see those heat lows developing very early, like September even before the monsoon, so I can see where the second half of your reply comes in now. Michael ----- Original Message ----- From: Anthony Cornelius To: Sent: Monday, 15 May 2000 20:55 Subject: Re: aus-wx: cold fronts and warm fronts > Hi Michael, > > Cold fronts are thought to be one the processes that trigger the > monsoonal onset. For example, the monsoon generally requires the > presence of the Pilbara and Cloncury lows to be present. This draws in > a moist inflow from the tropical oceans. However, it then presents a > sharp moisture discontinuity over the northern Australia region (over > land), as you have tropical maritime air, and tropical continental air > beside each other. However, there's no real disturbance besides the two > heat lows/troughs - and while the atmosphere is unstable to about 700mb, > due the to nature of heat lows/troughs generally anti-cyclonic > conditions occur above 700mb, thus adding subsidence to the area. So > you have a quasi-state equilibrium over the area, and no real trigger to > spark off convection. A cold front is thought to be one of three > triggers that allow the monsoon to fully develop. It displaces the > tropical continental air and since the heat trough is dependent on heat, > moves northwards into the moist (unmixed) tropical maritime air. This > adds further convergence to the air, and is thought to be a trigger. > Convection then breaks out on the northern side of the trough. > > The other two methods are thought to be anticyclogenesis causing > barotropic instability (it is sometimes associated with a cold front > too, and is thought to have a similar effect...however increases > horizontal wind shear in the E'lies). And the other method is > considered to be an extension of a long wave trough. > > None the less...these methods (at least in my opinion), could also have > a negative effect should they occur at the 'wrong' time, or have other > systems associated with them. > > I'm curious about the cold fronts triggering monsoons on the other side > of the equator though! This is most difficult to conceptualise... > > Michael Thompson wrote: > > > > Mmmmmm! usually a strong front associated with a massive high is what kills > > the monsoon, establishing the SE trades, and the front hardly ever makes the > > tropic of Capricorn. My amateur opinion anyway. > > > > Michael > > > > > It's funny you should say that. In class the other day when we were doing > > > front formation, our lecturer was talking about how the BOM is very > > > conservative with their depiction of fronts. He sited cases where cold > > > fronts had travelled up to trigger Monsoonal activity *across* the > > equator, > > > wow! > > > > > > Cheers, > > > Lyle > > > > > > > > > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > > 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------------------------------ > > -- > Anthony Cornelius > Queensland Coordinator of the Australian Severe Weather Association > (ASWA) > (07) 3390 4812 > 14 Kinsella St > Belmont, Brisbane > QLD, 4153 > Please report severe thunderstorms on our Queensland severe thunderstorm > reporting line on (07) 3390 4218 or by going to our homepage at > http://www.severeweather.asn.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------------------------------ > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: Mon, 15 May 2000 22:26:50 +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, Yes I agree Anthony. An interesting post. Though, I must say that some of the heat lows/surface troughs tend to develop even as early as late July or August - at least in the Kimberly region and then gradually extending south into the Pilbara region. In a couple of cases, this has then teamed up with a strong cold front and a NW cloud band forming East Coast Lows in ENSW and floods. Always something to watch. Jimmy Deguara At 21:45 15/05/00 +1000, you wrote: >Thanks Anthony, you learn something everyday and that was one thing I >certainly never knew about ! > >You do see those heat lows developing very early, like September even before >the monsoon, so I can see where the second half of your reply comes in now. > > > >Michael > >----- Original Message ----- >From: Anthony Cornelius >To: >Sent: Monday, 15 May 2000 20:55 >Subject: Re: aus-wx: cold fronts and warm fronts > > > > Hi Michael, > > > > Cold fronts are thought to be one the processes that trigger the > > monsoonal onset. For example, the monsoon generally requires the > > presence of the Pilbara and Cloncury lows to be present. This draws in > > a moist inflow from the tropical oceans. However, it then presents a > > sharp moisture discontinuity over the northern Australia region (over > > land), as you have tropical maritime air, and tropical continental air > > beside each other. However, there's no real disturbance besides the two > > heat lows/troughs - and while the atmosphere is unstable to about 700mb, > > due the to nature of heat lows/troughs generally anti-cyclonic > > conditions occur above 700mb, thus adding subsidence to the area. So > > you have a quasi-state equilibrium over the area, and no real trigger to > > spark off convection. A cold front is thought to be one of three > > triggers that allow the monsoon to fully develop. It displaces the > > tropical continental air and since the heat trough is dependent on heat, > > moves northwards into the moist (unmixed) tropical maritime air. This > > adds further convergence to the air, and is thought to be a trigger. > > Convection then breaks out on the northern side of the trough. > > > > The other two methods are thought to be anticyclogenesis causing > > barotropic instability (it is sometimes associated with a cold front > > too, and is thought to have a similar effect...however increases > > horizontal wind shear in the E'lies). And the other method is > > considered to be an extension of a long wave trough. > > > > None the less...these methods (at least in my opinion), could also have > > a negative effect should they occur at the 'wrong' time, or have other > > systems associated with them. > > > > I'm curious about the cold fronts triggering monsoons on the other side > > of the equator though! This is most difficult to conceptualise... > > > > Michael Thompson wrote: > > > > > > Mmmmmm! usually a strong front associated with a massive high is what >kills > > > the monsoon, establishing the SE trades, and the front hardly ever makes >the > > > tropic of Capricorn. My amateur opinion anyway. > > > > > > Michael > > > > > > > It's funny you should say that. In class the other day when we were >doing > > > > front formation, our lecturer was talking about how the BOM is very > > > > conservative with their depiction of fronts. He sited cases where cold > > > > fronts had travelled up to trigger Monsoonal activity *across* the > > > equator, > > > > wow! > > > > > > > > Cheers, > > > > Lyle > > > > > > > > > > > > > > > > >+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > > > 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------------------------------ > > > > -- > > Anthony Cornelius > > Queensland Coordinator of the Australian Severe Weather Association > > (ASWA) > > (07) 3390 4812 > > 14 Kinsella St > > Belmont, Brisbane > > QLD, 4153 > > Please report severe thunderstorms on our Queensland severe thunderstorm > > reporting line on (07) 3390 4218 or by going to our homepage at > > http://www.severeweather.asn.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------------------------------ > > > > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > 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------------------------------ Date: Mon, 15 May 2000 08:39:55 -0400 From: "Leslie R. Lemon" Subject: Re: aus-wx: Warm fronts.... To: "INTERNET:aussie-weather at world.std.com" X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id IAA19397 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Michael: > Don't worry many of us intend too, there is just one complication, the > Australian Dollar is very sick. In the 1970's it used to be close to value > with the US dollar, then in the 1980's with deregulation it plummeted, but > usually hung on the same value as the Canadian Dollar, but the last three > months have seen it go into territory occupied by Asian currencies. I do understand this. But in any case I know some of you plan to storm chase in the plains in a year or two. I very much look forward to that and to meeting many of you....at least those who will be able to make it here. I would very much like to come there as well. But strong dollar or no, I just can't afford to do it; not in the near future anyway. 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------------------------------ Date: Mon, 15 May 2000 23:23:59 +1000 From: Anthony Cornelius X-Mailer: Mozilla 4.72 [en] (Win98; I) X-Accept-Language: en To: aussie-weather at world.std.com 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 Jimmy and Michael, I agree with you in regards to heat lows, and it's certainly an interesting point. The only thing that I can think of, is that the heating, and tropical moisture needed isn't there during the late winter/early spring times - which is present in late spring/early summer. While thinking a little further about the process of fronts displacing the heat trough, I thought that possibly the QLD heat trough might be an example - ie, during summer it sits over central QLD, and seperates tropical maritime air (DP's still in the high teens/low 20's), with the dry tropical continenal air (DP's in the single figures). This trough generally remains inactive (although not always), unless it's 'dragged' by a front, or another trough that's moving over NSW. It then brings the heat trough close to the coast, and during Jan-Feb is the cause of most of our thunderstorms, as the trough then has storms forming along the coastal sections. But we don't quite have the moist inflow, nor the trough permanently over us to have convection like the monsoon does. Jimmy Deguara wrote: > > Hi, > > Yes I agree Anthony. An interesting post. Though, I must say that some of > the heat lows/surface troughs tend to develop even as early as late July or > August - at least in the Kimberly region and then gradually extending south > into the Pilbara region. In a couple of cases, this has then teamed up with > a strong cold front and a NW cloud band forming East Coast Lows in ENSW and > floods. Always something to watch. > > Jimmy Deguara > > At 21:45 15/05/00 +1000, you wrote: > >Thanks Anthony, you learn something everyday and that was one thing I > >certainly never knew about ! > > > >You do see those heat lows developing very early, like September even before > >the monsoon, so I can see where the second half of your reply comes in now. > > > > > > > >Michael -- Anthony Cornelius Queensland Coordinator of the Australian Severe Weather Association (ASWA) (07) 3390 4812 14 Kinsella St Belmont, Brisbane QLD, 4153 Please report severe thunderstorms on our Queensland severe thunderstorm reporting line on (07) 3390 4218 or by going to our homepage at http://www.severeweather.asn.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------------------------------