Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Continental Climate]

Heights trying to build toward greenland? http://modeles.meteo...nh-0-120.png?18!! This really is the depths of fi though!!

Im probably wrong but that russian high is stopping the vortex dropping into scandi? Which is where we need it!!

Edited December 18, 2012 by Continental Climate

[Mark Bayley]

I can't believe cold lovers want a pattern reset, honestly I have seen people saying that before and well the next thing you know, the cold does not return for weeks!

I think we really have to watch out for those rainfall amounts, could be an awful lot of rainfall in parts of Northern England for example especially if the block holds firm!

And the South West!

[Continental Climate]

A very mild christmas period coming up if this run is to be believed http://modeles.meteo...nh-0-138.png?18!!

Who knows we may get the whole pattern to back westwards some more but unlikely enough to keep xmas cold unfortunately!! LOL Just goes to show what a crazy run the 12z was, good ol GFS!!

Still some interest in the hemespheric pattern i suppose, heres hoping for a chilly new year!!

Edited December 18, 2012 by Continental Climate

[Geordiesnow]

And the South West!

Wow that is a serious amount of rainfall, even in other parts of the country where the ground is already very wet!

This run did had a westward shift which meant Friday is a little colder than the previous run and there is more WAA going towards Greenland but I'll be very surprised if the mild air does not win now, just to what extent will it win out could be the main question and how long it will last for.

[cooling climate]

With the high to the east retreating we are better placed for a norherly incursion.

The quicker the high does this the better.

[nick sussex]

Same old story from the GFS, the run to run continuity is dismal.

Who knows maybe the mystery tour will be back on tomorrow but even if it does bring that bit of earlier interest with heights dropping to the north the high is only going one way.

And when that happens you want it catapulted back east and not hanging around.

Edited December 18, 2012 by nick sussex

[swilliam]

A very mild christmas period coming up if this run is to be believed http://modeles.meteo...nh-0-138.png?18!!

Who knows we may get the whole pattern to back westwards some more but unlikely enough to keep xmas cold unfortunately!! LOL Just goes to show what a crazy run the 12z was, good ol GFS!!

Still some interest in the hemespheric pattern i suppose, heres hoping for a chilly new year!!

Doesn't look in the very mild catergory to me except in the far S (even then just above average).

[Geordiesnow]

With the high to the east retreating we are better placed for a norherly incursion.

The quicker the high does this the better.

What Northerly? I see an alarming trend of the PV heading into Greenland, don't see any sustained Northerly happening at the moment.

[swfc]

Im struggling to make any sense od where gfs is going her????The pv looks dizzy moving from west to east and vice versa!!It is taking a battering at 170hrs"fi"but pressure builds popping up everywhere on the nh charts

[Panayiotis]

I think the Russian high will become more of nuisance as its still showing in Fi :L http://cdn.nwstatic....192/h500slp.png As its stopping the PV going into Russia and forcing it into Greenland

Edited December 18, 2012 by Panayiotis

[Continental Climate]

LALA land i know but look at that severe cold getting into the US http://modeles.meteociel.fr/modeles/gfs/runs/2012121818/gfsnh-1-192.png?18!!! -10's getting right down into nevada and new mexico -20's into montana!!

Galling really considering how far north we are in relation to them!! A true continental climate!!! (p.s. i know we are maritime so i dont need an explanation)

[Shunter]

Nearly every operational GFS run over the past two days has made westwards movement of the Russian HP in its early timescale and every time its been dismissed by the Professionals and amateurs alike. Seems to me this large HP cell is retrogressing slowly towards Iceland and maybe beyond. The computer models logic does not see this and corrects to norm as soon as possible on each operational run giving the impression that the HP is slowly decaying or being moved back East. Maybe just maybe everyone has underplayed the synopsis unfolding before us ?

[Buriedundersnow]

well it was good to yet again see early upgrades and i'm gonna stop looking past 72-96 hours as past there it can all change depending on upgrades or downgrades.

[Iceaxecrampon]

This is seriously bonkers....

Daffs will be popping at this rate.

Ian

[nick sussex]

Well looks like British Gas profits will be taking a tumble!

You can always rely on the GFS to go from cold tease to barbecue weather in one run, putting the GFS aside the negative PNA pattern is doing us no favours.

Some one order some upstream amplification!

[Mark Bayley]

What Northerly? I see an alarming trend of the PV heading into Greenland, don't see any sustained Northerly happening at the moment.

Although not the on the ECM. Personally if we are not going to see anything from that high to the east i would much prefer something similar this mornings 0z ECM

http://www.netweathe...ction=ecm;sess=

This isn't without support from the ensemble means. Would at least open up the change for brief northerly spells

With the potential for the trough to finally shift into Europe and the high backing off

This is also supported by the Geopotential height chart from the ECM showing the core of the PV in the Siberian sector

I would be more inclined to trust the long range ECM than what the GFS is showing!

Edited December 18, 2012 by Mark Bayley

[Continental Climate]

This is seriously bonkers....

Daffs will be popping at this rate.

Ian

That is repulsive to look at!! Lucky it wont happen!!

[Panayiotis]

We normally see the 18z being the best run for cold, out of all the runs in the day, but in the last couple of days, seems it prefers to be sober and not produce anything wintry even in Fi....

[Bristawl Si]

How many xmas parties is it now that the GFS 18z has been on over the last week or so?!

As yet again it stumbles thru the back door, trying its best not to wake the rest of the household! LOL

[Cheshire Freeze]

Well looks like British Gas profits will be taking a tumble!

You can always rely on the GFS to go from cold tease to barbecue weather in one run, putting the GFS aside the negative PNA pattern is doing us no favours.

Some one order some upstream amplification!

Those heights over Central & Southern Europe have been there in FI for the last 3 runs. That, to me, is concerning; especially considering if it was a GH showing up we'd call it a positive trend.

[swfc]

For what its worth my local forcast has now changed from 4-7 dgs sat and sleet and snow on high ground is now rain.bbc just showed the low steaming in saturday!!!For me im going for fi at 72- 90 hrs.Atlantic looks nailed on to push threw eventually tho

[pdiddy]

This is seriously bonkers....

Daffs will be popping at this rate.

Ian

Only maxima of 7-8C at the surface though...

[TEITS]

Im still going to sit on the fence whether the 12Z GFS was on the right track. The evidence suggests it was wrong but even if all the ECM ensembles are against the pattern shown on the 12Z GFS can they all be wrong? Well the answer is yes because I have seen occasions when they have all been wrong. Also considering how the models continue to change I feel as though ensembles are worthless at the moment.

Lets look at +48 and then rewind the clock.

http://www.wetterzentrale.de/pics/Rtavn481.png

Were the models suggesting this when at the +144 timeframe? The answer is no and the models for this period we're actually indicating very mild SW,lys.

What is basically happening with the model output as the +0 to +72 timeframe gets closer is the models are backing the HP further W with a tendancy of SW going underneath the HP i.e the +48hr output. So when we look at the ECM/UKMO at +96/+120 can we honestly say that the LP will push the HP out of the way resulting in milder SW,lys. What could still happen is like the 12Z GFS suggested and that is the HP isn't pushed away and the LP decides to undercut the HP rather than push it away E. If we again look at the +48hr charts then you cannot say it won't happen again.

The model output has the potential of showing a sudden E,ly that I remember occuring in the 1980s. So don't be surprised to wake up one morning and discover at +72 the models are predicting an E,ly rather than a mild SW,ly.

[If Wishes made Weather]

Unfortunately not the first run to put western Europe under a HP cell between Christmas and New Year sandwiched between two PV lobes. Nice to see the jet going off into Africa however, and the absolutely smashed vortex, but it goes to show that despite what ought to be good base conditions, we can still end up with un-winter like weather.

[Guest]

We normally see the 18z being the best run for cold, out of all the runs in the day, but in the last couple of days, seems it prefers to be sober and not produce anything wintry even in Fi....

That all depends where you live! There is something wintry for some parts of Scotland on the majority of the high-res frames of tonight's 18z GFS...