Model Output Discussion 12z 27/11/2012

[nick sussex]

Yes the beginning of characteristics of a SW slipping SE I think?

Yes but look at the next little complication with that residual energy left to the north, we need rid of this aswell. Overall this was far too nerve wracking with that shortwave taking an age to sink south.

[Cheshire Freeze]

I can almost taste those -15's so close yet so far!! http://www.wetterzen...s/Rtavn1082.png!! A little more robust blocking to our north and that pesky shortwave further south and bingo, this is close to being quite special!! -15's over a warm north sea we all know what that means

That ship has sailed now. I'm more interested in SE diving shortwaves against an increasingly cold slab of air just to our east.

Edited November 27, 2012 by CreweCold

[nick sussex]

Ok this is okay so far but take a look at that shortwave to the se of Iceland at 126hrs this needs to get nuked.

What this does is stop the ridge from extending further west and allows the low to edge east for a while, without that the track would be more se.

[TEITS]

I can almost taste those -15's so close yet so far!! http://www.wetterzen...s/Rtavn1082.png!! A little more robust blocking to our north and that pesky shortwave further south and bingo, this is close to being quite special!! -15's over a warm north sea we all know what that means

Thats not going to happen YET!

Remember the bitterly cold E,lys always were unlikely as I suggested a few days ago. Our best chance of pulling in those very cold E,lys is for the the blocking to remain to our N and the LP in the Altantic sliding SE. This opportunity may present itself around the 5th Dec in future model outputs.

[phil nw.]

Just a reminder of John H`s latest analysis of the Upper Air charts also copied into the technical thread.

the review of the 500 mb charts and their predictions over the last 4-5 days for next week

review of 500mb outputs nov 28 2012.pdf 588.17K

[Jonan92]

Trying to set a new blocking link again?

[Continental Climate]

Thats not going to happen YET!

Remember the bitterly cold E,lys always were unlikely as I suggested a few days ago. Our best chance of pulling in those very cold E,lys is for the the blocking to remain to our N and the LP in the Altantic sliding SE. This opportunity may present itself around the 5th Dec in future model outputs.

yeah ive got to give up on those initial -15's no point flogging a dead horse i suppose and the time period around the 5th also ties in with GP's winter forecast of a cold period setting in round early to mid december, onwards and upwards I suppose!!

[Panayiotis]

Although the reliable timeframe is still uncertain the 06z run and this run have shown low pressure in the Atlantic bringing warm southerly winds at 144hrs. Despite this the overall NH pattern still looks good with the PV split.

Edited November 27, 2012 by panayiotis

[Cheshire Freeze]

Although the reliable timeframe is still uncertain the 06z run and this run have shown low pressure in the Atlantic bringing warm southerly winds at 144hrs.

That chart doesn't show warm southerly winds. It's actually close to an undercut and CAA from the east. The LP is just too well formed and situated too far north for us to benefit from that scenario though.

[Continental Climate]

Now that is a heck of a cold pool to our north east if we can tap into that http://www.wetterzentrale.de/pics/Rtavn1562.png!! On reflection TEITS i would say more like the 8th-10th for some proper cold

[The Eagle]

Look at all that cold air to the east waiting to be tapped

[NorthYorksWeather]

Not a bad run in the reliable time frame still plenty of snow chances although it looks like elevated area's in the North may be most beneficial. If we can get that colder air further west and the angle of attack from the Atlantic slighter further south then it's game on, and it wouldn't take much tweaking for this to happen.

[chionomaniac]

Although the reliable timeframe is still uncertain the 06z run and this run have shown low pressure in the Atlantic bringing warm southerly winds at 144hrs. Despite this the overall NH pattern still looks good with the PV split.

Maybe in Cardiff - but away from thesouth and west the temperatures don't get above 5C

[Southender]

Better disruption of the PV in the mid-range as well. And better ridging into Greenie. Encouraging.

[Panayiotis]

That chart doesn't show warm southerly winds. It's actually close to an undercut and CAA from the east. The LP is just too well formed and situated too far north for us to benefit from that scenario though.

I can see your point, but if look at the uppers...

[Cheshire Freeze]

Attempt two to initiate here I think....

The high over North Atlantic should start to build north at this point on this run. The pathway to Greenland looks clear to me.

Edited November 27, 2012 by CreweCold

[beng]

Now that is a heck of a cold pool to our north east if we can tap into that http://www.wetterzen...s/Rtavn1562.png!! On reflection TEITS i would say more like the 8th-10th for some proper cold

Yes - even if the slider low does introduce some milder air (not certain yet), if we get the ridging in the Atlantic behind it, then the floodgates could well open properly.

Edited November 27, 2012 by beng

[LomondSnowstorm]

Surprised no one's noticed the heights building in the mid Atlantic towards Greenland with a more amplified upstream pattern:

FI of course, but quite promising all the same...

[January Snowstorm]

Some serious cold building to our Northeast.

If we do get a 2nd bite of the cherry and pick up a Northeasterly wind my God will it be bitter!!

We would likely see record breaking cold

[Isolated Frost]

I can see your point, but if look at the uppers...

Isn't that around average for the time of year?

[bluearmy]

the occlusion barely clears the east coast on this run. we get a shortwave at the foot of the disrupting trough. all good indicators for the slider scenario.

[Biggin]

Although the reliable timeframe is still uncertain the 06z run and this run have shown low pressure in the Atlantic bringing warm southerly winds at 144hrs. Despite this the overall NH pattern still looks good with the PV split.

Do you think so?? for me a newb, those "southerlies" dont originate from somewhere warm but are rotating round a complex low situation and will hardly be warm, but what do i know

[The Eagle]

This is actually a really cold look run between 120hrs and 180hrs. Not far from something very special. A little tweak here and there and we are in.

[Panayiotis]

Maybe in Cardiff - but away from thesouth and west the temperatures don't get above 5C

Yes sorry I was a biased to my location. Edited November 27, 2012 by panayiotis

[ukpaul]

Good to see low being pushed back west at 186h, the low resolution will probably have none of it but a good sign. A very similar run than we have for a number of days for down here, so it's good to see something interesting coming into the nearer time frame.