Model Output Discussions 12z 01/09/2016

[Summer Sun]

Some higher parts could have a dusting of snow next Monday

Edited October 31, 2016 by Summer Sun

[Ali1977]

The GEM looks quite different at 162 with more heights building into Scandy.  More runs needed but I think a cold weekend is certain, it's the longevity of this cold spell that isn't.

Edited October 31, 2016 by Ali1977

[swfc]

17 minutes ago, Steve Murr said:

Very very good afternoon so far

GFS good to about 162- you can it trying to drop energy south - however after that the GFS rolls all the energy eastward

UKMO - superb with the 524 line in the NE at 144 indicating a high chance of snow falling !!

steve given theres very little waa going up towards greenland ete whats to stop the jet steaming out of the eastern seaboard? cant see it tbh but eh im not an expert tbh.thanks 

[knocker]

The key this morning with the GFS, and is still this evening, was the orientation and movement of the upper trough once phasing with the incoming upper low Friday had been completed, in combination with the outflow from the Canadian vortex and the strength of the Atlantic ridging. It looks like it may be leaning towards the ecm with the neg, tilted trough slipping SE, brief ridging  and troughs approaching from the north west/

But the HP holds up quite well and thus the quite strong jet, 100+Kts, runs west-east north of Scotland so initially the new troughs tracking east are not prone to slip SE, until day 10 when a repeat of the amplification occurs with a trough aligned over Scandinavia and strong ridging to the west and another brief burst of cold northerlies.

 

Summary

A cool, sometimes wet, grotty weekend which could feel quite cold in the easterly but warming up quite nicely for a couple of days in the middle of the week for some decent Sidney time.

Edited October 31, 2016 by knocker

[SMU]

SWFC ^^ Scandi Heights blocking & splitting the jet

look at the GEM

Edited October 31, 2016 by Steve Murr

[karlos1983]

I feel like we've gone full circle here in the past few days, Showing cold, then mediocre cooling, back to danm right chilly again. You can't beat model watching when the chances of cold are on the table. Fantastic stuff.

Unsure what the uppers translate to on the UKMO, I've lost the cheat sheet. If someone could post that would be great.

impatiently awaiting the ECM now, but a good afternoons model watching so far! 

[Mucka]

A quick look at GFS ensembles and a wide range possibilities on offer day 6 onward. We can expect lot's of chopping changing in future operational runs.

Edited October 31, 2016 by Mucka

[West is Best]

Blimey. This is actually a better chart than anything showing on the 6z.That had a lot of cold upper air but this one is a synoptic tantaliser:

 

 

November 1985 Redux. An almost identical chart:

That led to this:

Notice the absence of a Greenland High and yet it was one of the coldest Novembers in the history of CET (4.1C) and we went on to have some bitterly cold spells that winter including the February CET of -1.1C. 

The signs are very promising: cold pools moving very early into the right place and, apart from anything else, the air and ground temps are about to take a big hit.

Edited October 31, 2016 by West is Best

[Frosty.]

These temperatures from the Gfs 12z will be a shock to the system when you add on the windchill factor, well below average with increasingly frosty nights and even before then the uk will see its first widespread frost of the season on wednesday morning...The first of hopefully many, many, many!

Edited October 31, 2016 by Frosty.

[northwestsnow]

Is there potential for a scandy high on the ukmo 144?

 

[Summer Sun]

If what GEM shows is right it will be feeling very chilly mainly due to the strength of the wind next weekend and into the following week with some rain too

Anything slightly milder is reserved for D10

One thing that is noticeable is just how much of eastern Europe sits under milder air

Edited October 31, 2016 by Summer Sun

[Frosty.]

23 minutes ago, Summer Sun said:

If what GEM shows is right it will be feeling very chilly mainly due to the strength of the wind next weekend and into the following week with some rain too

Anything slightly milder is reserved for D10

One thing that is noticeable is just how much of eastern Europe sits under milder air

Speaking of mild, realistically I don't see anything more than short-lived milder interludes during the next 2 to hopefully 4 weeks with winds generally from north of west drawing mostly rPm or Pm and occasionally Am air down across the uk.

Edited October 31, 2016 by Frosty.

[Summer Sun]

After the high teens and low 20's in the south today the weekend will be a big shock to the system!

[Frosty.]

The Ecm 12z shows an increasingly cold unsettled weekend with 528 dam, windy on saturday but the isobars open out a little by sunday but still a very chilly feel..certainly when you consider west Wales reached an amazing 22c 72f today.

Next Monday looks  with 524 dam across the SE!

Edited October 31, 2016 by Frosty.

[Nouska]

1 hour ago, karlos1983 said:

Unsure what the uppers translate to on the UKMO, I've lost the cheat sheet. If someone could post that would be great.

Is this what you are looking for?

[I remember Atlantic 252]

522 needed here Frosty off that setup, not going to be pleasant 

[Summer Sun]

Next Monday looks very cold in the east and a strong wind for good measure

By Tuesday the low finally pulls away allowing some less cold air into the west as winds slowly shift around to a west to north westerly

 

Edited October 31, 2016 by Summer Sun

[northwestsnow]

ECM is interesting, and its also a pretty chilly run generally in the reliable timeframe.

the 168-

http://old.wetterzentrale.de/pics/Recm1681.html

Is intersting because we do have a scandy high in place...

 

[SMU]

ECM has 524 thicknesses in the SE & 168

using the UKMO cheat sheet

for NE england I get -5.7 850 ( along 535 contour ) & that darker patch just off the coast -7.7 along the 532/533 contour !!

 

Notice all the models this eve hold back the atlantic !

S

[Frosty.]

5 minutes ago, I remember Atlantic 252 said:

522 needed here Frosty off that setup, not going to be pleasant 

524 dam would be mighty impressive, especially considering how warm autumn has been so far, particularly September. I would of course like a prolonged cold spell with 510 dam but I think I will have to wait until winter for that.

Edited October 31, 2016 by Frosty.

[karlos1983]

8 minutes ago, Nouska said:

Is this what you are looking for?

Thank you @Nouska that's the one 

[pdiddy]

Easterly incoming on the ECM...

 

[feb1991blizzard]

Lovely 216 for giving us another shot at better cold down the line.

[SMU]

& as if by magic the atlantic has to slide lows under the scandi high !

[Summer Sun]

In the space of 24 hours, ECM goes from a northwesterly to a west to southwesterly still cold in the east t240 could be interesting easterly possibly incoming

Edited October 31, 2016 by Summer Sun