Topic: Strong Cold Front SE Aust - Snow to Low Levels - 17 to 20 July 2007

[Jeff Brislane]

Hi,

We have a very strong cold front in the forcast bringing bitterly cold air with it from Tuesday through to Thursday morning. The air aloft is especially cold with this system and some forcast air temps aloft are -30 to -36 at 500mb and as low as -6 at 850. Forcast surface temps for Wednesday so far ar 2 for Orange, 3 for Katoomba, 4 for Goulburn, 5 for Canberra, Oberon should only make 0, -5 for Thredbo top allthough -8 might be more like it. The problem with this system though will be lack of miosture the further north you go. The snowy's should see 50cm from this system but the Central Ranges might only get a couple of centimetres in places but with CB's in the cold air there should be heavy isolated falls of snow I would think. The highest falls are forcast on the Central Tablelands for the southern and western slopes so places like Orange and Blayney or Crookwell should do well from this system.

Jeff.

[Jimmy Deguara]

Yes Jeff,

I was surprised very little was talked about in terms of this event unfolding once again over the Central Tablelands. My interest also with such cold air is its impact on Sydney and coastal communities as well. We'll see.

My experience suggests that usually some form of showers can occur in Sydney even in a westerly regime during particularly cold outbreaks.

Are you chasing Jeff? I have the next 7 weeks booked out myself.

Regards,

Jimmy Deguara

[Jeff Brislane]

Jimmy,

Maybe everyone is busy right now with school back on etc. This is a very potent cold air surge and we should see significant effects on the temp in Sydney tomorrow. This morning has seen frost here in Penrith with -1 and a chilly -3.5 so far at Richmond. You would have a bit of frost Jimmy? The main thing I don't like about this system is not the lower moisture levels but the fact that it's crossing overnight tonight. I much prefer a daytime passage for the photo opportunities so I'll see how it goes. It could be hard getting out there on Wednesday with sub zero temps across the mountains, as they'll likely close the GWH especially if it gets a dusting of snow. It is interesting that the BoM have upgraded the forecast for Katoomba on Wednesday to more likely snow showers so it could be a nice cafe day up there.

Jeff.

[Jimmy Deguara]

Given it is related to this thread, yes we have had another severe frost this morning and ice on the car. What surprises me is the frost is also close to the buildings. White all over of course.

Frost is lacking this season obviously due to the active rainfall pattern during June but July and August I think should see some pretty severe frosts.

So the temps for Richmond:  Sunday -1.5  Monday -2.9  and -3.4 this morning - not bad! Badgerys Creek recorded -3.5 this morning.

Regards,

Jimmy Deguara

[David C]

Quite a thick frost in southern sydney too -- the car was showing -1 on the display just before 8:00am, I'll callibrate it next week with a reference thermometer I am getting in for work, but I suspect it is pretty accurate.

I was just speaking to Paul at lunch over coffee and it is 21 years since that particularly cold day back in 1986, during which there were several reports of snow falling from around Sydney. I remember coming home from school and measuring 5C around 3:30pm and we had what appeared to be a snow shower around 4:00pm from a convective cumulus (of course whether this was snow is open to debate). Don White and some others seem to insist that these reports were of soft hail, however it would probably have been a 1 or 2C cooler with cold downdrafts and I think snow was certainly a possibility that afternoon. Will be interesting to see what happens tomorrow.

[Jimmy Deguara]

Hi David,

I was just speaking to Paul at lunch over coffee and it is 21 years since that particularly cold day back in 1986, during which there were several reports of snow falling from around Sydney

Yes it is 1986 but later July. The comparison is not the day maximum however but moreso the minimum that followed a couple of days later. It was a Friday afternoon when your suggested sleet and snow occurred which we experienced here. Two days later, the temperature dropped to -5 to -6 range at Richmond or something similar which is most likely one of the coldest morning on record. I think it is this minimum they are comparing to today and I guess specifically at Observatory Hill.

Just checked my records and it was 25th July 1986 when the sleet and snow occurred and 27th July when the very severe frost occurred. The days prior to the snow events were balmy and mild in the 25 to 27 C range if I recall. This severe frost on the 27th Kuly was so severe that a thick layer of ice formed in the bath tub cows used for drinking water. I remember because I pushed down with a stick and it would not break! My father and I tried to open a gutter that was blocked (unrelated to the frost) but we simply had to go back inside as out hands were killing us haha. The maximum on this day was only 10C but still that represents a decent minimum maximum spread haha and it rained most of the morning. This followed 4 other mornings that year in the -4C range.

Regards,

Jimmy Deguara

[Michael Bath]

Looks like the only places to get snow to low levels were in Victoria on Tuesday, notably the hills surrounding Melbourne. Snow line got to about 300 metres elevation, with settling snow from about 400 metres up. The system dried out fairly quickly once it passed the southern ranges, though snow still fell in the hills around Canberra and the Central Tablelands down to about 900 metres.

Temp here at present (7pm) is 9.5 which is impressive for here. Might get another record low temp by morning.

MB

[Jimmy Deguara]

News articles indicate that both Lithgow and Orange got snow today - the maximum temperature at Orange was 2C! Any other news regarding this?

Regards,

Jimmy Deguara

[Michael Bath]

No - haven't heard any more reports of snow around that area during yesterday. Satpics showed significant low cloud cover in that area that may have been capable of some very light snow showers.  Keep a check on the weather news

Got a min of 4.6 this morning here at McLeans Ridges, though the district seems to have got a lot more cold minimums than Monday morning - plenty of -2 to -4 type readings which is approaching record territory for July at Northern Rivers sites.  One notable thing is the very low dew points. My AWS got to -7.5 - the lowest I have seen in the previous 6 years I've had this running is -4.  Plenty of DP obs in the past 12 hours or so were around -10 at official sites. Very dry.

The local newspaper here, The Northern Star show a frost/fog photo of mine (taken Monday morning) in this morning's edition. They also promoted my NSW Northern Ranges Snow Chasing Guide which is great - nice prominent link.

MB

[Jeff Brislane]

Hi Guys,

I went out to Oberon with Kim on Tuesday night and stayed overnight in town. The snowfall there was quite good and nothing like the bad reports i've heard from other areas on the Central Tablelands. The town itself picked up about 2cm of snowfall with most falling between 9pm and 11pm. The snow on the front of the cloudband was too wet to settle as the temp wasn't low enough and there wasn't enough omph in the cloudband to push cold air down but it didn't last long as the temp dropped to freezing by about 920 or so and dry powder started falling and accumulating rapidly.

On Wednesday morning there was snow on everything and due to the cold temps and lack of sunshine in large doses it stuck around for most of the day which is a change from warmer events that see complete thawing by lunchtime. We headed out into the country side and were greeted with even thicker quality powder snow. South of Oberon we measured snow to 5cm deep and due to constant cloud cover there it didn't melt at all above 1200m all day.

We also headed out to Kanangra Walls in the afternoon and there was snow cover on and off almost all the way out there and there was also patches of snow on the lookout at Kanangra at 3pm at only 1000m asl! On the way back the snow on the road hadn't changed a bit and will still be there this morning. We also encountered snow still present in the shade at Jenolan Caves House which is only 850m asl! On the way out we saw snow here and there all the way to about 5km past Hampton at 430pm where it finally stopped.

All in all it was a nice couple of days and the snow quality was excellent and deep in areas I expected for this type of system. The only downfall was not the so called lack of moisture but the passage during nighttime allthough it probably accounted for more snow due to a lower initial temp.

Jeff.

[Jimmy Deguara]

Hi Michael,

Please feel free to indicate the latest story on your link to the snow - the media story. Good snow forecast resource by the way!

Regards,

Jimmy Deguara

[Michael Bath]

Lismore Airport site below zero by midnight, though temps have not gone as low as the morning before. The prolonged frost is going to have more major impacts on local crops. On the ABC rural report just now a blueberry producer a few ks SW of me (on the Alstonville Plateau) reported a temp range yesterday of -6.5 on the lowest part of his property, up to -1 on higher parts. A stone fruit producer near Bangalow reported -9 in the lowest gullies up to zero on the higher ground.

The early freeze last night seems very unusual for the Northern Rivers as much as it is for Southeast Queensland.

Only got down to 5 C pre-dawn here, which has since risen to nearly 8 by 7.30am due to a freshening westerly.

MB

[Michael Bath]

Satpic loops have been uploaded for this event.

Southeast Aust 16/07/2007 00z to 18/07/2007 00z [2.7mb]

Australia 15/07/2007 00z to 18/07/2007 23z [9.9mb]

[Jane Gough]

It's certainly been a rewarding few days in the outer East of Melbourne! I travelled to The Dandenongs on Tuesday 17th and Wedsnesday 18th. Tuesday I was treated to constant sleet with the odd flake falling, but not settling at the time I was there. Unfortunately, the colder air had yet come through, so after hearing the reports of snow at Olinda that evening, I drove up there again on Wednesday morning. What a sight!







It was all pretty sloshy and slippery at that stage, and I made the decision not to drive up to the top of Mount Dandenong (there was also fog with visibility down to around 50m and less in patches.). All in all it hads been a rewarding few days with snow, rain, thunder, lightning and hail...what more could you ask for?  . I've ended up with 31mm for the event, bringing my July total to 71mm.

Full set of images are online here, report will follow shortly!

http://www.stormygirl.net/chase180707.htm

[Michael Bath]

Peter Burr posted this link on Weatherzone. For those who don't use that forum, I encourage you to have a look at this link to Peter's website, and the ice photos taken at Ebor Falls near Dorrigo on 17th and 19th July.

http://www-personal.une.edu.au/~pburr/weather/images1.html

Extraordinary - it's not something I've even thought could happen.

MB