Model Output Discussion: 12Z (22/11/12) And On...

[Frosty.]

sooooo.....where do we go from 192??

To buy a snow shovel

A wintry blast now looks very likely, I liked how JH said he thinks it will last 7-10 days, that gives plenty of scope for further upgrades in longevity with reloads until deep into december.

[chiffer]

sooooo.....where do we go from 192??

Fingers crossed, Stay cold! id like to say its to far out to justify, however 144 is a long time away!

[Geordiesnow]

Also, our best friend (the azores high) is keeping a watchful eye on us the whole time to see are we lonely!!

Good ECM but not briliant

Again, the depth of cold is not brilliant(which in fairness has been the trend) but there is no real sign of a block breakdown on this run, nor there is on the GFS which now I think i'm starting to think about, its a decent run with perhaps more longer term potential than the ECM(GFS has -15 uppers over Scandi, ECM is heading into positive figures).

I think the only thing that is making people nervous and most certainly myself is the lack of cold air to play with at the start which as I have been saying for days may come back and haunt us if blocking does not get into the right places. In normal circumstances, what the models are showing this evening should be very snowy runs, as it is, there more just quite cool and wet!

Be interesting if the other models go for the more northerly trend which again under normal circumstances won't be a bad thing but because of the Arctic high could well stay over svalbord region for a while, then the uppers are milder than they would if Svalbard was under an PV!

[ITSY]

Problem is, there's no cold pool to our east to tap into. Eastern Europe has 850s above 0c at 216 and 240hrs I think it's going to be sleetmagedon end of next week

Very true. I am a tad less convinced about the severity of this cold spell after this afternoon's/evening's outputs. UKMO is certainly a massive consolation

[chris55]

You gotta laugh at this, now ECM wants to drag up a toasty easterly due to the cut of high forming to the far north east!!!!

http://www.wetterzentrale.de/pics/Recm2162.gif

What the final outcome will be I have no idea, and neither do the models.

[Mucka]

And just to show the GFS is plausible in the mid term JMA throws up something similar but it has better ridging behind and turns out very nice anyway.

http://www.meteociel...44-21.GIF?23-12

So even if that low does burst through in a worrying manner we will still have a decent chance of quickly rebuilding the block behind which is why on balance I think we will be okay. Twists and turns to come though.

http://www.meteociel...92-21.GIF?23-12

Edited November 23, 2012 by Mucka

[snowking]

ECM for me is a bit of a tease out at 240

Atlantic ridge meeting scandi ridge, LP cut off to hold it up, and renewed push of WAA into the arctic, re-developing arctic HP

Shame its still so far out, but a satisfying run for now within the reliable. I'm not looking at specific detail much beyond 72hrs....if you take a look at the 850 profiles on the UKMO and ECMWF, virtually identical, thats as much as I need to know for now.

SK

[Mr Frost]

The thing I can't get my head around on here is the amount of 'blind faith' people seem to be exuding. At times the weather makes mockery of even seasoned forecasters and there is no guarantee or certainty of any outcome. Even if something is highly probable, it's still not certain. the GFS 12z remains a plausible solution and IMO people are being foolish consigning it to the 'bin' or 'shredder' (two phrases which are really starting to grind my gears just lately).

I'm trying to provide a balance to some of the more exuberant posts on here over the past few days!

To be fair you seem to swing back and forth more the models. Relax.

A balance? You were calling the zonal express to be arriving shortly on the winter thread 10 days ago. As a wise old man say's (Sorry John) don't get hung up on every run, look for the trends. You are constantly swinging from positive to negative with every GFS run.

Enjoy the ride!

[kumquat]

I'll take the ECM from an IMBY POV. 6 days of -4 to -8 850s from T120 onwards. For the beginning of December this is pretty exciting.

[tinybill]

evening just had to post this i know its F 1 but it looks nice!!

[Gowon]

http://www.meteociel.fr/modeles/jma.php

JMA has updated and it's similar to the GFS at 144 but looks better later on.

[Zenarcher]

ECM is great tonight lets compare it to yesterday and see the changes,

28th November - The low to the south of Greenland not as strong and the pressure to our North today is much stronger.

Yesterday

Today

29th November - Pressure to our North once again looking higher which is good also the low pressure system entering the Atlantic has been made weaker,

Yesterday

Today

30th November - The low that was to the SW of Greenland doesn't appear today. Pressure to our North still looking better.

Yesterday

Today

I've just compared the upper temps from today and yesterday's and today's is much colder with the cold air pushing more South down to around -5c and for the North of the UK -8c. A great set of runs this evening with all the models showing a blocked cold pattern.

Edited November 23, 2012 by weathermaster

[AWD]

I'll take the ECM from an IMBY POV. 6 days of -4 to -8 850s from T120 onwards. For the beginning of December this is pretty exciting.

I agree. The ECM offers cold & snow for a few days at the end of next week.

How long it lasts, who knows & I don't personally care, the ECM would offer a nice opening to winter for me.

[nick sussex]

Some good news from upstream, they go with the ECM ensemble mean, they've not included any operationals in their final update:

PRELIMINARY UPDATE...

RELIED ON THE 00Z/23 ECENS MEAN TO UPDATE THE PRELIMINARY FRONTS

AND PRESSURES FOR DAYS 3 THROUGH 7

FINAL...

MADE ONLY COSMETIC CHANGES TO THE UPDATE PACKAGE FOR THE FINAL

ISSUANCE. BOTH THE 12Z/23 GFS AND GEM GLOBAL HAVE DRAMATICALLY

CHANGED THEIR TUNE WITH THE HANDLING OF THE WAVE CROSSING THE

MIDWEST AND EAST DAYS 3 AND 4, NO LONGER SENDING A DEEP LOW

NORTHEASTWARD INTO NEW YORK STATE. BOTH OF THOSE MODELS SQUASH THE

DEVELOPMENT, WITH A MUCH SHARPER LIMITING STREAMLINE TO THE NORTH.

THE ECMWF CONTINUES TO BE OFF TO THE RACES AND FLAT WITH THIS

SYSTEM, WITH A DRY OVERALL FORECAST. THE GFS HAS TRENDED TOWARD

THE EUROPEAN CENTRE GUIDANCE WITH THE ENERGY IMPINGING ON THE WEST

COAST AS WELL, WITH A CONTINUED PREFERENCE TOWARD THE STEADY EC

THERE.

Interestingly on the diagnostic discussion they've ditched both the GFS and ECM operationals for the key system crossing the Great Lakes and have used the UKMET/GEM/GEFS mean.

THE UKMET/CANADIAN

GLBL/REG GEM GENERALLY SUGGEST SOME DEGREE OF COMPROMISE WITH THE

GEFS MEAN ALSO HEDGING A LITTLE AWAY FROM THE GFS AMPLITUDE ALOFT.

FASTER NAM TRENDS OVER THE PAST COUPLE DAYS AT LEAST SEEM TO

FAVOR A SOLN FASTER THAN THE SLOW SIDE OF THE SPREAD. THUS PREFER

AN INTERMEDIATE FCST AMONG THE UKMET/CANADIAN GLBL/GEFS MEAN.

At this point we want neither the GFS or ECM to verify for Europe so anything that suggests they might be wrong with the pattern in the eastern USA is to be welcomed!

Edited November 23, 2012 by nick sussex

[Snowy Easterlies]

yes the uppers look cold enough for snow on the ECM but how much snow will there be? a lot of the time we get the cold uppers and its dry, even though those charts show low pressure over us with those blues

[Weathizard]

Would much prefer a slow start and get some mild muck out the way first so we can get some serious prolonged cold rather than 2-3 days of below average temps and a bit of wet snow, I remain convinced we'll get a good period of below average temperatures, so many different routes we could go down though

[chris55]

Oddly it seems to me that it's the Azores high that we need for all this to come off. If it can ridge freely north/north east and link with the encroaching Arctic high then we are away, however it looks as though the shortwave moving off the tip of southern Greenland is just enough to stop this, and in turn the Azores high sitting in residence actually holds back the CAA from the north east!

[Severe Siberian icy blast]

Although the short waves on the ECM look to be the spoiler , the fact that we have -5 upper air or lower and are sitting under low pressure means it may turn out quite snowy, it then pumps warm air up into Europe and gives us yet another mildish easterly . . .doubt very much it would turn out like that but time will tell, so another twist in the models this evening , and the gfs goes off on one of those typical runs in fi.

[peterf]

link?

[Paul]

ECM is here Peter

http://www.netweather.tv/index.cgi?action=ecm;sess=

[J10]

Form an IMBY point of view, ECM looks very good with a North West wind for next weekend and cold uppers. However there remains big variations in the charts for next weekend/ The roller-coaster is get to go on for a few more days yet.

[Liam J]

The BOM is where it's at tonight, perfect evolution as the Arctic high sets up home close to northern Norway sending the shortwaves packing towards Biscay. Shame it's just the BOM!

http://www.meteociel.fr/modeles/bome_cartes.php?&ech=222&mode=1&carte=1

http://www.meteociel.fr/modeles/bome_cartes.php?ech=222&code=0&carte=1&mode=0&archive=0

[mountain shadow]

The models never ever get a proper handle on Greenland heights. Is seems to me they are underplaying height rises in that area compared to what we are expecting from the anomaly projections.

Lets not look for a breakdown until the cold actually arrived.

[Jason H]

RELIED ON THE 00Z/23 ECENS MEAN TO UPDATE THE PRELIMINARY FRONTS

AND PRESSURES FOR DAYS 3 THROUGH 7

<<SNIP>>

THUS PREFER

AN INTERMEDIATE FCST AMONG THE UKMET/CANADIAN GLBL/GEFS MEAN.

Interesting stuff. Thanks for posting this Nick. Still far from being modelled correctly.

Edited November 23, 2012 by Jason H

[No Balls Like Snow Balls]

I have taken a quick look at the big 3 on my mobile and at T120 they seem to be in a similar place to each other. I am not going to stress about the GFS at T144 as it was on the milder end of the ensembles. To sum it up still looking good for a cold spell.

Edited November 23, 2012 by No balls like Snow Balls