Storm Australian Severe Weather Forum
Severe Weather Discussion => General Weather - all topics not current severe weather. => Topic started by: Jimmy Deguara on 29 June 2008, 03:00:04 AM
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Just as a separate topic, this topic will encourage the more significant mornings in 2008 when frosts occur given it is a short period of time when such frosts occur.
This morning, the temperature dropped on of the coldest morning yet in western Sydney with 0.1C at Richmond.
Regards,
Jimmy Deguara
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I have been looking at this topic too. This June, the nights have been warmer than normal and I have had a look at the BOM weather stations for outer Sydney. A few other locations in the outer outer areas of Sydney have recorded similar minimum temperatures too over the past 2 to 3 nights:-
Bageries Creek
Thursday -0.4 C, Friday 0.2 C, Saturday 1.1 C
It is likely that there would have been a frost on Thursday and Friday morning here.
Camden
Thursday -1.6 C, Friday -0.2 C, Saturday 0.7C.
It is highly likely that there would have been some frost on all three mornings in some areas here.
Richmond
Friday -0.5 C, Saturday, -0.1 C
Same again.
So far, this is limited to these outer areas. Anywhere outside these areas have recorded minimums of 2 C and above. For comparison, the coldest morning so far this year at Blacktown is 3.3 C recorded 28/6/08 which is a little too warm for a frost.
Harley Pearman
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No frosts around the Lismore area yet, though not sure if temps have cooled enough around Grafton so far this year. This morning however dropped to 6 at my place which is fairly cold for here (at the top of a hill). Stratocumulus pre-dawn soon pushed the temp back up.
Temps have approached -10 in the southern parts of the Northern Tablelands around Walcha this week.
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Harley,
I have just checked and it seems there are some inaccuracies in your readings above. I like reading your comprehensive reports so it would be excellent to have this checked for any future reference. Do you think you may have ready the dew point or apparent temperature readings rather than the actual dry bulb temperature readings on the Bureau of meteogology website?
Michael, the -10C for the Walcha area and I suspect similar type of temperatures near Armidale in the hollows are just incredible considering the lowest temperature recorded in western Sydney is -8.3C at Richmond in 1970 from memory.
Regards,
Jimmy Deguara
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I am wondering too about temperature measurements. I have an outdoor (cheap) thermometer setup that is sitting about 3 foot off the ground. I have caught it reading zero early this week first thing in the morning, but there was no sign of frost (just some dew). So I don't know whether to believe it.
Not my preferred setup but lost the old max/min thermometer in Adelaide.
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Gyday all thought this would be worthwhile adding a few Pics from Ron in Walcha. He creates an ICETREE in his back yard the other weekend when they had -9 overnight.
(http://www.australiasevereweather.com/rodney/icetreea.jpg)
(http://www.australiasevereweather.com/rodney/icetreeb.jpg)
(http://www.australiasevereweather.com/rodney/icetreec.jpg)
(http://www.australiasevereweather.com/rodney/icetreed.jpg)
(http://www.australiasevereweather.com/rodney/icetreee.jpg)
(http://www.australiasevereweather.com/rodney/icetreef.jpg)
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Amazing effect - Ron used a fine mist from a garden hose to create the icicles. I wonder how cold the air temp must be for this to work - just less than zero, or much colder ?
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Jimmy
Thank you for advising me. I am curious now and I am not quite sure how the minimum temperatures are taken at the various sites. I had a look at the "Daily temperature readings" for various locations in the BOM web site and noted the minimums recorded. These are found in the Daily Observations Weather. In this case, for NSW.
I did some checking of the minimums noted at Weatherzone as well to match up and this is what I found for those mornings 26/6/08 to 30/6/08:-
Richmond
Thursday 2.9 C, Friday -0.5C, Saturday 0.0 C Sunday 0.7C Monday -0.1 C
Badgerys Creek
Thursday -0.4 C, Friday 0.2 C, Saturday 1.1C, Sunday 0.4C, Monday -1.1 C.
Camden
Thursday -1.6 C, Friday -0.2 C, Saturday 0.7 C, Sunday 0.1 C, Monday -2.4C
As you say there may be variations and differences to these, I would be very interested in learning more about this. Thank you.
Harley Pearman
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Actually Harley,
You are correct. I was checking the half hourly temperature BoM data and not the actual absolute minimum records so it is could be correct and not necessarily what I had suggested. Good that you verified as I know you are pedantic when it comes to statistical records. Thanks for that.
Regards,
Jimmy Deguara
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Cold mornings in Liawenee (Tasmania)
Yesterday, I read a report on Weatherzone Weather News concerning what is described as a "Super cold snap" in which the residents of a small town called Liawenee in the Central Highlands of Tasmania (Western edge of Great Lake) on Lake Highway about 56 km south of Deloraine woke up to a minimum temperature of -9.6 C at 6 am.
However upon investigating this and checking the official weather station at this site, I think this cold is worth reporting here:-
Tu 1/7/08 Min Temp -1.8 C, Max temp 2.3 C
We 2/7/08 Min temp -1.8 C, Max temp 0.9 C
Th 3/7/08 Min temp -1.7 C, Max temp 2.8 C
Fri 4/7/08 Min Temp - 10.7 C, Max temp 4.9 C
Sa 5/7/08 Min temp -9.8 C, (Max temp not available as I type this at 11.13 am).
Rather cold on Friday and Saturday mornings. Locals confirm the coldest period here since the weather station was operational in 2001.
There is also a photograph of Mt Wellington (Same storey) bathed in the early morning sunrise with snow down to low levels.
Harley Pearman
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I see that morning temperatures in your country are not so low as i taught. :)
I was expecting temp. around -10. I remmember when there was -20°C here. That was the morning temp. And the max day was around -1
It is better not to have so low temp.
I love the ICETREE pictures :)
Regards,
Andy
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Australia has a wide range of temperatures, mainly due to it's size. But most of the population live near the coast (different from Slovenia!) and the low elevation and proximity to water generally keeps the temperatures within reason in most capitals.
From wikipedia the hottest every recorded is 50.2 C at Oodnadatta in South Australia, the coldest -23 C at Charlottes Pass which is near Australia's highest mountain (which isn't that high by world standards).
Canberra is probably the coldest capital city in Australia for minimum temperatures, because it is situated inland at a fair elevation. It gets a little bit of snow that rarely settles every couple of years. The alternative is Hobart in Tasmania which is at water level so while it gets snow I don't know if the temperatures overnight get quite as low.
My personal experience living in Australia has ranged from -11 in Canberra (riding the bike to school was fun that morning, we got used to riding no hands with good gloves and the hands inside the jacket) to _+47 at Woomera in South Australia. Luckily in those outback areas humidity is very low so it doesn't feel as bad as Sydney or Brisbane 10 degrees cooler.
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The Liawenee (http://www.bom.gov.au/products/IDT60801/IDT60801.95959.shtml) observation site - elevation 1055 metres - has only been running since 2001. A local who lives at Miena, near Liawenee quoted in that ABC news report suggested it was the coldest morning for 25 years when -14 was reported.
You can see the snow on Mt Wellington from this excellent webcam:
http://www.rosebay.tased.edu.au/Camera.htm
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From wikipedia the hottest every recorded is 50.2 C at Oodnadatta in South Australia...
Funny, I thought the hottest temp recorded was Cloncurry QLD - +51.3c (source: BoM archives)
Big Pete
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From wikipedia the hottest every recorded is 50.2 C at Oodnadatta in South Australia...
Funny, I thought the hottest temp recorded was Cloncurry QLD - +51.3c (source: BoM archives)
Yes it surprised me as well (not that wikipedia is always reliable) as I thought the hottest place in Australia was Marble Bar WA. Had a quick hunt on the BoM site before I posted but couldn't find the link to the records.
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Saturday morning 12/7/2008 produced another noteworthy cold morning for western Sydney including:-
1.5 C where I live in Blacktown (The coldest morning so far this year).
Penrith 1.1 C.
Richmond had -2.5 C. This is the coldest morning so far this year.
Campbelltown had -0.6 C.
Camden had -1.1 C. Not quite as cold as the 30/6/08 where the minimum temperature fell to -2.4 C.
Still there would have been morning frost in these areas. I observed frost on car windows in my locality after sun rise.
Harley Pearman
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Quote from: Richary on 05 July 2008, 08:46:38 PM
From wikipedia the hottest every recorded is 50.2 C at Oodnadatta in South Australia...
Funny, I thought the hottest temp recorded was Cloncurry QLD - +51.3c (source: BoM archives)
Big Pete
Although not the focus of this thread, I thought I would touch upon the point.
Certain temperature and statistical records are being checked for their authenticity and some have unfortunately had to be laid to rest due to incorrect environments they were taken. In the case of Cluncurry, the thermometer was situated under a corrugated iron roof if I am not mistaken.
Regards,
Jimmy Deguara
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Some very cold mornings for July 2008 - New South Wales
I have been looking at numerous centres across New South Wales finding out which town or locality has woken to the coldest morning for the month. Some places have fittingly suffered frosts and cold mornings. The coldest minimums that I can find across the state for July are as follows:-
Armidale - Located on the Northern Tablelands at an elevation of around 980 metres should be mentioned. The coldest mornings are:-
Minus 9 C on the 12, Minus 6.6 C on the 17 and minus 6 C on the 31.
The average minimum temperature for the month is Minus 0.6 C.
Goulburn - Located on the southern Tablelands at an elevation of around 630 metres received Minus 6.7 C on the 23.
Oranage Located on the Central Tablelands at an elevation of around 888 metres received Minus 5 C on the 23.
The coldest of the coldest must go to Charlotte Pass where the temperature fell below Minus 12 on the following days, 5 - Minus 12.5C, 12 - Minus 13 C, 23 - Minus 14C, 24 - Minus 15.5C, 25 - Minus 15.5C, 26 - Minus 12.5C and 30 - Minus 12.5C.
The average minimum temperature for the month was Minus 6.3C.
Note:- This does not even come close to the morning of 18 June 1994 when Minus 23 occurred which is still the coldest recorded temperature on the Australian continent at a weather station.
The morning of 31 July should also be mentioned here because some serious cold temperatures occurred. The coldest that I can find include Minus 5 at Barraba, Minus 7 at Woolbrook, Minus 6 at Armidale, Cooma and Inverell and Minus 5 at Mudgee.
Sydney:
The coldest that I can find is Minus 2.5 C at Richmond on the morning of the 12.
There were many other centres across the state that recorded low minimum temperatures for 31 July from 0 to minus 4 depending on location.
Harley Pearman
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Some cold mornings for August 2008 - For localities in New South Wales
I have been looking at the run of minimum temperatures across New South Wales for August (Period 1 to 14 August)and so many places have had a significant run of cold mornings. Following the last frontal system and with still but clear nights with no cloud cover, minimum temperatures below 0C have been a feature across wide swathes of the state.
I would suspect too that the early morning frost that is occurring would be harming unprotected crops in the inland areas of the state. The following places are worthy of mention in this post as this is significant for August.
Armidale
The average minimum temperature for August 1 to 14 stands at minus 3.1C. On the 9, the minimum temperature fell to minus 6.6C, 10 - minus 7.8C, 13 - minus 6.9C and 14, the minimum temperature fell to minus 5.1C. The temperature has fallen below 0C on 11 out of 14 mornings to date.
This is reflected in the daytime maximums struggling to reach to 6.5C to 11.3C between 6 and 13C on the various days.
Barraba (North west NSW)
This small town has experienced 11 out of 14 nights where the minimum temperature has plunged below 0C. The coldest was on the 13 and 14 in which minus 6.1C was recorded here.
The average minimum temperature during this period stands at minus 3.1C.
Charlotte Pass (Snowy Mountains)
Cold mornings are typical here but minus 10.5C stands out on 5/8/2008. The average minimum temperature is minus 5.3C to date.
Coonabarabran (North west slopes and plains)
Special mention here given that minus 5.2C occurred on the 5/8/2008 and minus 1C occurred on 11,12 and 13.
Glenn Innes (Northern Tablelands at an elevation of 1,030 metres)
This is incredible in which 12 out of 14 mornings has seen the minimum temperature drop below 0C. The coldest being minus 5C on the 3, minus 6C on the 8 and minus 6.5C on the 9.
Goulburn (Southern Tablelands)
Worth a mention given that minus 4.7C occurred on the 4 and minus 5.6C occurred on the 5.
Guyra (AT 1,300 metres in elevation on the northern tablelands)
Not as cold as Armidale with the coldest being minus 4.3C on the 14.
Lithgow (At 930 metres on the Central Tablelands)
A reading of minus 5.4C occurred on the 4.
Tamworth (At 430 metres in elevation NW slopes)
This is amazing in its own right. A reading of minus 4C on the 9, minus 4.4C on the 12, minus 4.9C on the 13 and minus 6.3C on the 14.
The days are averaging 14C and are sunny but the nights have averaged minus 1.3C for the period.
Temora had minus 1.9C on the 14.
The run of cold nights have occurred across wide swathes of the state leading to frost. However, it is not limited to inland areas and the hills. The coast is getting it too although not as bad such as.
Richmond (NW Sydney):
A reading of minus 2.6C on the 9, minus 2.3C on the 12 and minus 2.6C on the 14 has occurred.
Murwillimbah had minus 1C on the 10 and Coffs Harbour had 1.4C on the 12, 1.3C on the 13 and barely 1.1C on the 14.
I have also read reports on Weatherzone in which some very cold nights have occurred in inland SE Queensland and even as far out as Charleville.
Where I live in Blacktown, minimum temperatures have fallen between 1C and 4C still very cold and well below the average minimum of 6.8C.
Harley Pearman
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Harley,
We have had several consecutive mornings with frost here in Schofields and this includes ice having to be removed off the windows on a few of these mornings. It is the first time I recall that August have had colder and more consistently colder mornings than July.
Can anyone confirm this?
Regards,
Jimmy Deguara
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1.8 is the coldest we've had so far this year. I don't know whether this is low enough for light frost, HOWEVER, last July brought full on frost when the temp dipped to -0.7 on the 20th.
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Steven,
In response to your 1.8C temperature, this is sufficient for frost but it depends on the ground temperature which at times can be up to a few degress lower than your screen temperature. I have observed frost even when temperatures have been 5C but this is in particularly dry air situations and during periods when significant frosts have been observed prior lowering the mean ground temperature.
Regards,
Jimmy Deguara
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We had a few frost in Coffs over this period, not sure how many exactly but I woke up to see 3 was probably a couple more but I didnt get up for them. Took photos on the 13'th
(http://i27.photobucket.com/albums/c172/enak12/August%2013%202008%20-%20frost/IMG_0802copy.jpg)
(http://i27.photobucket.com/albums/c172/enak12/August%2013%202008%20-%20frost/IMG_0799coy.jpg)
(http://i27.photobucket.com/albums/c172/enak12/August%2013%202008%20-%20frost/August%2017%202008%20-%20moon%20halo/IMG_0854copy.jpg)
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Been a few frosts around the Northern Rivers district over the past three weeks since the rain stopped - in fact there has been no rain since 28th July.
This is in the valley below my place on 31st July though there have been many mornings like this during August.
(http://australiasevereweather.com/photography/photos/2008/0731mb01.jpg)
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MB,
Thats a great example of sinking cold air and a pretty good reason why I wouldn't want to live in a valley!!
Roughly, what sort of temperature difference was there from your place to the valley in your photo? I'm interested as to how much difference there is with night time temperatures between hills and valleys.
James
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Hi James - I measured 8.8 as the min that morning. We are about 120 metres higher than the lowest part of the valley. It's typically 7 degrees warmer here than below - quite a difference. Of course that rule only applies for the clear, dry and still nights.
Lowest temp I've had this winter is 5.7 on the 12th August and the low parts of Lismore was getting minus 1.
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Steven,
In response to your 1.8C temperature, this is sufficient for frost but it depends on the ground temperature which at times can be up to a few degress lower than your screen temperature. I have observed frost even when temperatures have been 5C but this is in particularly dry air situations and during periods when significant frosts have been observed prior lowering the mean ground temperature.
Regards,
Jimmy Deguara
Well I haven't seen many frosts at these temps (around my area especially), perhaps once before when it got down to about 2-3C and I actually braved the cold to get out. :)
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Michael and James,
Even though the valley here in Schofields is relatively shallow - only perhaps a 20 to 30 metre drop, there is a significant difference in the frequency of frosts and their severity.
Another point worth raising is the eastward versus westward facing slopes. My parents chose this farm based on its inclination which obviously has a flow on effect on the health of plants and their growth in market gardening. Now I wonder if there is a correlation between the health of humans and animals given the above mentioned factors...
Regards,
Jimmy Deguara
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Hi Steve,
I am specifically going to point out the importance of drier air and rate of cooling at the surface in the rarer cases of frost occurrences at say 4-5C. Where you are, I assume the dew points are relatively higher (moister air) so perhaps this may be the reason? Any other comments?
Regards,
Jimmy Deguara
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With regard to height being a factor, I used to live near Gosford and would often wake up to hear on the radio it was 2 degrees or something similar in Gosford. Walked outside (aprox 80m ASL) and thought it's not that bad. As I walked down the hill to the train (about 10m ASL) you would suddenly strike a temperature change where it dropped several degrees in the matter of a few steps. Only on still days of course.
That said, where I am now at Rydalmere we are higher than Parramatta or Olympic Park weather stations by about 20m but it is often colder here than reported at those sites - I guess the proximity to the water may keep those areas a bit warmer?
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Cold air sinks called katabatic winds and cold air will pond in any low spot especially during a clear winters night. I have seen this occur so often. Cold air is more dense than warm air and being colder, it will sink to a lower elevation even if the rise or hill is not very high. The top of a hill can be warmer than the valley below. This certainly more prevalent on clear winter nights.
Jimmy, I have seen the frosts that have been occurring in outer north west Sydney on several mornings now and saw it again last Sunday morning too. I agree with you.
It is shaping up as the coldest August in a long time and almost daily I am seeing unusually low minimum temperatures being set somewhere. I have not seen this occur before. I read a report yesterday suggesting that this is starting to look like the coldest August in 10 years but I have seen other figures and quotes suggesting that this August is colder than that. I am not sure who is right. One thing is certain, the cold nights has become a weather event in itself and one that many have noticed.
Consider these minimums since my last post here.
Tenterfield
The August nights have been colder to date than that of July. Some unbelievable cold nights include minus 7.2C on 9, minus 8.3C on the 10, minus 7.1C on the 12 and a hard to fathom minus 9.5C on the 14. It was minus 6.6C on the morning of the 20.
Woolbrook
Minimums include minus 7.5C on the 10, 13 and 20, minus 8C on the 14 and minus 7C on the 19.
Armidale
The problem that Armidale suffers is that the town is built between North Hill and South Hill and is in a valley. Cold air ponds in this valley causing much colder temperatures. Obviously being 980 metres above sea level also helps. I think the weather station is at 2AD Radio Station in town (It was when I was at University from 1990 to 1993). If I am wrong please correct me.
Armidale had another minus 7.4C on the 20, minus 6C on the 19 and minus 6.6C on the 18.
Tamworth:
This regional city is at the foot of the Moonbi Ranges in the north west slopes. I am amazed that minus 4C was recorded again on the 20. The cold is occurring here too.
Gunnedah had minus 4C on the 20 and Coonabarabran had a minus 5C on the 20 too.
Glenn Innes
Glenn Innes is at the foot of a rise too but elevated 1,030 metres above sea level. The minus 9C on the 20 is incredible.
Yet Thredbo being higher in elevation had minus 5C. It was colder in Glenn Innes on the morning of 20/8/08 than at Thredbo.
However, a place called Eyre in Western Australia (Coordinates appear to be 32 15 degrees south and 126 18 degrees east as this is not a town) has set a new Western Australian weather record for minimum temperatures on the morning of August 12 being minus 7.2C. It beat its previous record of minus 5.9C on the morning of June 14 2006. However it is qualified that weather records begun only in 1983 but records from the nearby telegraph station go back to 1885. It is the coldest temperature recorded anywhere in Western Australia.
Hence, it is not confined to New South Wales or southern Queensland. It is more widespread.
Harley Pearman
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Hi all,
For the first time in many years I had on Friday morning a 1 inch thick layer of ice on my car. Also Melbourne area experienced its first Black Ice warning in many years.
Just a nibbler for the winter-freaks.
Big Pete
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Another cold morning 24/8/08
After a few nights respite from the cold, large areas of New South Wales suffered through another cold morning on 24/8/08.
Evidence is emerging that August 2008 is shaping up as the coldest in 10 to 30 years varying from place to place partly due to the cold mornings that have occurred.
I saw frost again in outer north west Blacktown Sunday morning. Additionally some towns across NSW had the coldest night for August. A sample of places that suffered again include:-
Woolbrook had minus 6C, Barraba minus 5C, Condobolin had minus 4C, Dunedoo minus 3C, Cootamundra minus 4.5C (The coldest morning this month), Temora minus 4C, Wagga Wagga minus 3.4C (The coldest morning this month), Young minus 4.6C, Armidale minus 5.4C, Inverell minus 4C, Lithgow minus 5.8C, Cooma, Mudgee and Tenterfield all had minus 5C.
Many other centres had minimum temperatures of between 0C and minus 3C.
Charlotte pass had minus 14C being the coldest of all places.
Given that is was again widespread, it would be interesting to see the damage the frost is causing to any crops that have been sown in the affected areas. Yet the frigid nights are occurring so late in August and in some areas, there has been little respite for the whole month.
Harley Pearman
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These photos were taken by Martha from the Guyra Argus newspaper yesterday morning (25th Aug). It was the first frost this season with a bit of moisture about - there was a heavy overnight fog.
(http://australiasevereweather.com/photography/thumbs/2008/0825ga01.jpg) (http://australiasevereweather.com/photography/photos/2008/0825ga01.jpg)
(http://australiasevereweather.com/photography/thumbs/2008/0825ga02.jpg) (http://australiasevereweather.com/photography/photos/2008/0825ga02.jpg)
(http://australiasevereweather.com/photography/thumbs/2008/0825ga03.jpg) (http://australiasevereweather.com/photography/photos/2008/0825ga03.jpg)
(http://australiasevereweather.com/photography/thumbs/2008/0825ga04.jpg) (http://australiasevereweather.com/photography/photos/2008/0825ga04.jpg)
(http://australiasevereweather.com/photography/thumbs/2008/0825ga05.jpg) (http://australiasevereweather.com/photography/photos/2008/0825ga05.jpg)
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Hi Steve,
I am specifically going to point out the importance of drier air and rate of cooling at the surface in the rarer cases of frost occurrences at say 4-5C. Where you are, I assume the dew points are relatively higher (moister air) so perhaps this may be the reason? Any other comments?
Regards,
Jimmy Deguara
Hi,
Well it was a particularly dry morning and dew points were quite low (although they're usually high at that time), that obviously explains this scenario. Oh and there was no wind whatsoever! Can't really have frost development without calm clear conditions.
Steve