From: wbc at ozemail.com.au (Laurier Williams) To: aussie-weather at world.std.com Subject: Re: aus-wx: QUESTION re Dewpoints Date: Sat, 07 Oct 2000 17:34:34 GMT X-Mailer: Forte Agent 1.5/32.452 X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id MAA03543 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com On Wed, 04 Oct 2000 17:40:56 +1000, Anthony Cornelius wrote: >Hi Jane, > >FP = Frost Point...since the DP is the temperature that you have to >reduce the air to form due...well, if the DP is negative, if that >temperature is reached, you won't get dew...but frost. I just call it >FP - although sometimes I just call it the DP. > Hi Anthony This distinction has been bugging me for a while. I thought there was something wrong but couldn't remember what, so I checked a few books and it's all become clear again :-) Dew point is the temperature to which air has to be cooled to reach saturation with respect to *water*, while frost point is the temperature to which it has to be cooled to reach saturation with respect to *ice*. This distinction becomes clearer when you think of observers making their temperature wet and dry bulb readings and humidity calculations. There's a different set of calculations depending on whether they are reading a wet bulb or an ice bulb (i.e. the wet bulb is frozen). The difference between a *wet* and dry bulb is used to measure the latent heat of vaporization (i.e. the heat required to convert water to water vapour), while the difference between an *ice* and dry bulb is used to measure the latent heat of sublimation (i.e. ice to water vapour without an intermediate fluid stage, but equal to the latent heat required to convert ice to water + water to vapour). At 0 degrees C: latent heat of fusion (ice to water) = 79.67 calories/gram latent heat of vaporizion (water to vapour) = 597.26 cal/gm which equals latent heat of sublimation (ice to vapour direct) = 676.93 cal/gm If a dry bulb is +2.0C, and wet bulb -1.0 (i.e. water supercooled, not frozen), the result is a dew point of -8.3, but the same temperatures with the wet bulb frozen produces a frost point of -6.7. So dew point can be below 0, and frost point is always 0 or below. The distinction is only whether it was measured with a wet or ice bulb. So a dry bulb temp of 35 with a wet bulb of 15 gives a dew point of minus 22, not a frost point. Laurier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: wbc at ozemail.com.au (Laurier Williams) To: aussie-weather at world.std.com Subject: Re: aus-wx: TV Series October/November Date: Sat, 07 Oct 2000 17:43:39 GMT X-Mailer: Forte Agent 1.5/32.452 X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id MAA07069 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com And of interest to all chasers: Storm Chasers - join the film-makers of Australia: Eye of the Storm as they embark on a 2 year quest to capture unique images of animals living with flood, fire, drought, blizzards and cyclones. ABC TV, Sunday October 15, 6.30 pm See http://www.abc.net.au/nature/storm/chasers/default.htm Laurier On Wed, 4 Oct 2000 16:15:41 +0800, "Steve Summers" wrote: >Hi All >Upcoming TV series AUSTRALIA - EYE OF THE STORM. on ABC at 2030 on the following dates >LA NINA...........Wed 25th October >SOUTHERN EXPOSURE........Wed 1st November >EL NINO......................Wed 8th November >MONSOON................Wed 15th November > >A natural history series that describes the powerful climate systems that batter Australia and how they effect the weather, wildlife and the people of this island continent. > >Further details abc.net.au/storm > > >Cheers >Steve +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: wbc at ozemail.com.au (Laurier Williams) To: aussie-weather at world.std.com Subject: aus-wx: ASWA and the Bureau forecast monopoly, was Sydney Forecasts & their Accuracy Date: Sat, 07 Oct 2000 18:19:12 GMT X-Mailer: Forte Agent 1.5/32.452 X-MIME-Autoconverted: from quoted-printable to 8bit by europe.std.com id NAA15928 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com On Sat, 07 Oct 2000 03:57:30 +1000, Don White wrote: snip >Sure, we all make mistakes and the chaos theory input into the weather >makes it the challenging science that it is but the sooner the >restrictive copyright practices that the Bureau places on the use of raw >data collected at the Publuc expense are changed and it allows a bit of >public competition, the better... we will all benefit. Don, those on the list may not be aware that anyone gaining access to Bureau data must sign an agreement not to issue public forecasts that (a) differ from the relevant Bureau forecast, or (b), if issued for elements not included in the Bureau forecast, are "inconsistent" with the Bureau forecast. I presume ASWA has signed such an agreement in gaining access to Bureau radar and FTP data. As a result, any ASWA member putting on the Internet a forecast which is inconsistent with the Bureau's is in effect breaking that agreement. I wonder what the reaction would be if economists were prevented from issuing forecasts inconsistent from those of Treasury or risk having the data on which their forecasts relied cut off? While I don't think anyone would disagree that there should be one source, and only one source, for *warnings* so as to avoid confusion, the effective limitation on public *forecasting* has, IMHO, serious ethical, scientific and practical problems. I find it sad that the meteorological community in Australia, schooled in the scientific ethos of disciplined competition, allows this to happen without demur, for decade after decade. -- Laurier Williams Australian Weather News & Links http://ausweather.simplenet.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-Authentication-Warning: new-smtp2.ihug.com.au: Host p54-max60.syd.ihug.com.au [203.109.164.54] claimed to be storm.ihug.com.au X-Sender: jdeguara at pop.ihug.com.au X-Mailer: QUALCOMM Windows Eudora Version 5.0 Date: Sun, 08 Oct 2000 06:08:40 +1000 To: aussie-weather at world.std.com From: Jimmy Deguara Subject: Re: aus-wx: ASWA and the Bureau forecast monopoly, was Sydney Forecasts & their Accuracy Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Laurier, My interpetation in the case of ASWA members putting forecasts on the internet that is different than the Bureau has really nothing to do with ASWA members so long as the forecast is not put under ASWA's name. Having said this, I would suggest anyone (particularly ASWA members) who does have a forecast on their web page make sure it is not placed under or linked to the ASWA name or logo. The most important thing personally is to make sure you put a disclaimer on your site so that businesses etc using your forecast don't claim compensation of any sort against individuals. I find this lack of freedom of choice pathetic. Jimmy Deguara At 06:19 PM 7/10/00 +0000, you wrote: >On Sat, 07 Oct 2000 03:57:30 +1000, Don White > wrote: > >snip > > >Sure, we all make mistakes and the chaos theory input into the weather > >makes it the challenging science that it is but the sooner the > >restrictive copyright practices that the Bureau places on the use of raw > >data collected at the Publuc expense are changed and it allows a bit of > >public competition, the better... we will all benefit. > >Don, those on the list may not be aware that anyone gaining access to >Bureau data must sign an agreement not to issue public forecasts that >(a) differ from the relevant Bureau forecast, or (b), if issued for >elements not included in the Bureau forecast, are "inconsistent" with >the Bureau forecast. > >I presume ASWA has signed such an agreement in gaining access to >Bureau radar and FTP data. As a result, any ASWA member putting on the >Internet a forecast which is inconsistent with the Bureau's is in >effect breaking that agreement. > >I wonder what the reaction would be if economists were prevented from >issuing forecasts inconsistent from those of Treasury or risk having >the data on which their forecasts relied cut off? > >While I don't think anyone would disagree that there should be one >source, and only one source, for *warnings* so as to avoid confusion, >the effective limitation on public *forecasting* has, IMHO, serious >ethical, scientific and practical problems. I find it sad that the >meteorological community in Australia, schooled in the scientific >ethos of disciplined competition, allows this to happen without demur, >for decade after decade. > > >-- >Laurier Williams >Australian Weather News & Links >http://ausweather.simplenet.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------------------------------ ----------------------------------------- Jimmy Deguara Storm Chaser and Mathematics Teacher from Schofields, Sydney NSW Australia e-mail:jdeguara at ihug.com.au Web Page with Michael Bath Australian Severe Weather Home Page http://www.australiasevereweather.com President of the Australian Severe Weather Association 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------------------------------ Date: Sun, 08 Oct 2000 09:23:57 +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: QUESTION re Dewpoints Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi Laurier, Thanks for this - I actually forgot about the extra energy needed for sublimation vs vapourisation! Is there a formula to convert DP to FP then without knowing the ice-bulb temperature? AC Laurier Williams wrote: > > On Wed, 04 Oct 2000 17:40:56 +1000, Anthony Cornelius > wrote: > > >Hi Jane, > > > >FP = Frost Point...since the DP is the temperature that you have to > >reduce the air to form due...well, if the DP is negative, if that > >temperature is reached, you won't get dew...but frost. I just call it > >FP - although sometimes I just call it the DP. > > > Hi Anthony > > This distinction has been bugging me for a while. I thought there was > something wrong but couldn't remember what, so I checked a few books > and it's all become clear again :-) > > Dew point is the temperature to which air has to be cooled to reach > saturation with respect to *water*, while frost point is the > temperature to which it has to be cooled to reach saturation with > respect to *ice*. > > This distinction becomes clearer when you think of observers making > their temperature wet and dry bulb readings and humidity calculations. > There's a different set of calculations depending on whether they are > reading a wet bulb or an ice bulb (i.e. the wet bulb is frozen). > > The difference between a *wet* and dry bulb is used to measure the > latent heat of vaporization (i.e. the heat required to convert water > to water vapour), while the difference between an *ice* and dry bulb > is used to measure the latent heat of sublimation (i.e. ice to water > vapour without an intermediate fluid stage, but equal to the latent > heat required to convert ice to water + water to vapour). > > At 0 degrees C: > > latent heat of fusion (ice to water) = 79.67 calories/gram > latent heat of vaporizion (water to vapour) = 597.26 cal/gm > which equals > latent heat of sublimation (ice to vapour direct) = 676.93 cal/gm > > If a dry bulb is +2.0C, and wet bulb -1.0 (i.e. water supercooled, not > frozen), the result is a dew point of -8.3, but the same temperatures > with the wet bulb frozen produces a frost point of -6.7. > > So dew point can be below 0, and frost point is always 0 or below. The > distinction is only whether it was measured with a wet or ice bulb. So > a dry bulb temp of 35 with a wet bulb of 15 gives a dew point of minus > 22, not a frost point. > > Laurier > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > 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: "McDonald" To: Subject: Re: aus-wx: WEATHER: Did anyone else see this at ~6pm today....? Date: Sun, 8 Oct 2000 12:39:58 +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 Robert, I noticed this band of cumulus congestus and the updrafts were very crisp. Two areas along this line seemed to punch a little higher than the rest. One I would guess to have been either just over the CBD or just N of the CBD and the other was probably over the inner western suburbs. At a guess i'd say the tops could've hit 18-20000ft. Also of note yesterday was the strong shear in the lowest 6km of the atmosphere (at that time). Surface winds were from 240 degrees (SW) at about 20knts, 700mb winds were 280 degrees (WSW) at about 50knts and 500mb winds (~6km) were from 340 degrees at 80knts. As you can see there is 100 degrees of directional shear and 60knts of speed shear. I don't know if this would have anything to do with it but it could. The radar at the time actually pulsed into the "pink" (40-100mm/h) briefly. I actually took some video of this band of congestus and I will get around to doing some captures sometime this week so everyone can see. I'm glad I wasn't the only one to get a little excited about this (yeah - we could do with a decent storm...hehe). Andrew McDonald. ----- Original Message ----- From: Robert Goler To: Aussie-wx Sent: Saturday, October 07, 2000 9:22 PM Subject: aus-wx: WEATHER: Did anyone else see this at ~6pm today....? > > Hi all > > A band of cumulus congestus passed through Melbourne around 6:00pm today. > I observed it from my 11th floor room, 20km to the southeast of the CBD, > as it passed over the CBD, with some small scuddy, raggedy lowerings > present here and there...no drama here. > > At 6:08pm I noticed a full, fat, conical shaped lowering extending from a > smooth base. The tallest buildings in the CBD are about 1 degree high, and > this lowering would not have been greater than 1/4 degree (width at widest > point would have been less than this). It was noticeable with the eye, and > particular so with my lil 8x21 binoculars. I managed to get a couple of > shots with my 300mm lens. It lasted for a couple of mins. > > Can anyone else confirm or deny what this was (ie at this stage I'm > thinking it was a funnel, but I could be wrong)? > > BTW Jane, I think the colours on the websites are good. > > > Cheers > > -- > > Robert A. Goler > > E-mail robert at mail.maths.monash.edu.au > http://www.maths.monash.edu.au/~robert/ > > Department of Mathematics and Statistics > Monash University > Clayton, Vic 3800 > Australia > > -- > > +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > 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: [203.54.90.9] From: "S G" To: aussie-weather at world.std.com Subject: aus-wx: Weather later this week Date: Sun, 08 Oct 2000 11:21:58 CST X-OriginalArrivalTime: 08 Oct 2000 01:51:58.0962 (UTC) FILETIME=[58513D20:01C030CA] Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Looks like some interesting weather could develop later this week in Adelaide and the lower south east of the continent. Some models are forcasting an intense low to develop just south of Adelaide with some fairly low pressures extending all the way up to the SA/NT border. Some fairly warm temperatures ahead of this trough/cold front and low pressure system as well. This could be a repeat of early October last year in Adelaide when we had thunderstorms throughout the day and then some heavy rain during the evening before the low pressure system passed through Adelaide. One thing that is worrying me is the timing of the system there are a lot of descrepencies between all of the states on the timing of the system. Plus the eastern states aren't forecasting much out the system at all. Maybe it will weaken as it moves east, hopefully it won't be weak to start with. As far as I'm concerned this system looks very confused at the moment. I would like to hear from anyone who could explain this system to me in a clearer manner. I would presume this system would form a rain band with embedded t'storms but so far Adelaide is only forecasting showers??? _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.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: raikman at austarnet.com.au To: Subject: aus-wx: New e-mail address Date: Sat, 7 Oct 2000 09:27:07 +1000 X-Mailer: Microsoft CDO for Windows 2000 Thread-Index: AcAv7PF1SfAI8JpSEdShZABQi5N8Gg== Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Hi everyone, This message is just to advise that I have a new e-mail address: raikman at austar.net.au Thanks Rod Aikman 42 Panton St, Golden Square, Bendigo, Vic +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: rossg at mail.eisa.net.au Date: Sat, 7 Oct 2000 09:20:12 +0930 To: aussie-weather at world.std.com From: Ross Goble Subject: aus-wx: Steady Rain in Adelaide Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com It's been raining here since about midnight, good soaking for the garden. Sorry no rain gauge, have to wait for the bom figures. No thunder claps either that I noticed - guess I've got a tad more time before I need to warm up the camera. Ross (Magill, Adelaide) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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: "Duncan & Mandy" To: Subject: aus-wx: Alice weather Date: Sun, 8 Oct 2000 14:07:03 +0930 X-Mailer: Microsoft Outlook Express 5.00.2314.1300 Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com Yesterday (Saturday) was the Henley-on-Todd boat race. Very hot and windy conditions which would've made things a little unpleasant for crowds and competitors. A trough moved though last night, bringing rain only to the West of here, but cooling things down. Today it's a cooler 30C, with cloud cover and a cool breeze. Perfect for carnivals - I bet the Henley-On-Todd organisers wish today was yesterday! cheers, duncan +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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, 08 Oct 2000 19:56:36 +1000 From: Keith Barnett X-Mailer: Mozilla 4.6 [en] (Win95; I) X-Accept-Language: en To: aussie-weather at world.std.com Subject: Re: aus-wx: TV Series October/November Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com I think this series has been shown before. If it's the one I think it is, it's as much on the animals and the environment as on the weather, with some simulated shots... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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, 08 Oct 2000 08:44:39 +1000 From: Don White X-Mailer: Mozilla 4.5 [en] (Win98; I) X-Accept-Language: en To: Aussie Weather Subject: aus-wx: Dry in Brisbane Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com I notice that 0.8 mm on 2 September is the only rain in Brisbane since 14 August - 0.8 mm in 56 days - is this some sort of record? Does anyone know what the longest rain free period in Brisbane is? Currently it's on 37 days and would be 56 day only for that miserable 0.8 ! don White +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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, 08 Oct 2000 23:48:06 +1000 From: David Carroll X-Mailer: Mozilla 4.74 [en] (Win98; U) X-Accept-Language: en To: Aussie Weather Subject: aus-wx: weather - Bathurst Sender: aussie-weather-approval at world.std.com Reply-To: aussie-weather at world.std.com 08/10 11.39pm HI all. Just heard thunder in Bathurst, went outside and saw several lightning flashes South towards Rockley, Oberon area. Rockley is 20 min south of Bathurst.. The Weather site lightning pics shows quite a bit of lightning from Bathurst to further out west. Weather radar showing small cell Orange, Bathurst and north to Mudgee, more lightning now Lithgow way. Dave +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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------------------------------