Model output discussion - 1st December onwards

[ITSY]

Anyone doubting the potential for a LONGER term pattern change just has to look at some of this evening's postage stamps. Nothing major in the medium term but lots to play for if we look further afield and assess the broader profile over the longer term. Might come to nothing but these options would suggest that something could be afoot as we move into the weeks ahead. As fergie said, we risk missing the wood for the trees if we fixate too closely on temp profiles, immediate snow potential and whether this or that easterly will materialise. Stick to longer term assessments of the broader profile and we'll see where things take us. Over to the strat people and the pros for a detailed understanding of WHY these changes may or may not happen, but some great charts to look at here. 

[nick sussex]

At T240hrs every single GEFS member has removed the Euro high so that's something to be thankful for. Typically it looks like  snow is set to arrive to the European ski resorts as the Christmas holidays finish!

Next weekends weather is looking very complicated, lots of precip about but what falls from the sky open to question.

The NH is undergoing changes and troughing over Europe rather than the Euro high dominated pattern. The Euro high seems to have been around for months and unfortunately set up in the worst position to direct countless lows into the UK .Unfortunately as we've seen mild in the UK winter inevitably means a lot of wind and rain.

In terms of next weekend its a messy complex affair with some extreme cold parked in eastern Europe , ordinarily we're talking of trigger shortwaves when it comes to easterlies, the stakes are normally raised very high because we're often left in the shortwave behaves itself or the Scandi high sinks outcome.

Its not that straightforward this time because no model wants to sink the block over Russia, the issue is if a lobe of high pressure can survive to the north to help force low pressure to disrupt and head se.

This was the joker that the ECM played when all looked lost, as everyone knows I wasn't enamoured with its run this evening. Not saying that it can't verify, we've seen before some fraught evolutions to cold but they do come with little margin for error.

In the background we do have the continued progression of the MJO so I think fluidity to the NWP is likely to continue, we should bear in mind that the Scandi/Russian block has largely come out of the blue and wasn't supposed to happen, was this an MJO response?

So next weekend is still I think a forecasting nightmare where anything could happen, lots of snow or lots of rain or a bit of both!

 

 

[Bullseye]

One of the things I have noticed is the main models going with the situation of the Scandi High moving east into Kara Sea/Russian High, the question would be what impacts this has on the UK compared to Scandi High looking at previous situations? Few American Meteorologists are also impressed by signal of Kara Sea High over time.

To add to this, Eric Webb on Twitter seems to think Kara Sea High has similar strength to January of 1897,1919,1926,1931,1942 ,1977 and 1995 so very few, shows how impressive a Kara Sea High of this strength would be.

Edited December 28, 2015 by Bullseye

[Due South]

Check out Big Joe B Twitter feed. First time he has spoken about the up coming weather for the UK this winter.

[A Frayed Knot]

Please tell us ' i for one don't have Twiiter

[Radiating Dendrite]

GFS 6z is a fairly similar run to the 18z. I may not have a meteorology degree but the problem is surely the fact that the high pressure is not a true scandi one but much further to the north and east. It never ridges far enough West to engage any low and send it SE into Europe. We are stuck in no man's land - looks a similar situation to a few years ago when Europe went into the freezer but we were too far West of the pattern and never tapped into the cold. 

[Smiler1709]

56 minutes ago, Radiating Dendrite said:

GFS 6z is a fairly similar run to the 18z. I may not have a meteorology degree but the problem is surely the fact that the high pressure is not a true scandi one but much further to the north and east. It never ridges far enough West to engage any low and send it SE into Europe. We are stuck in no man's land - looks a similar situation to a few years ago when Europe went into the freezer but we were too far West of the pattern and never tapped into the cold. 

This is the scenario that I think will play out this time next week. Big Siberian high to Far East to give us any true cold,  I want cold as much as anyone but you need near perfect model output to get cold and snow to our little island especially to lowland England. Hopefully we at least become drier so the poor people affected by the floods can get some much needed relief. 

[Liam J]

Not many comments on the 00z GFS, never a good sign! Unfortunately it turns into quite an unsettled run with frequent wet weather so would provide little relief for the flood hit areas. Near the end of the run the Azores high ridges in from the SW which would bring drier weather. 

ECM going for the undercut!

 

Edited December 28, 2015 by *Sub*Zero*

[knocker]

A difference of opinion regarding mid week between the METO and gfs. Whichever way you hack it there will be some wet and windy weather.

Edited December 28, 2015 by knocker

[Cheshire Freeze]

ECM keeping the dream alive this morning...looks decent from what I've seen thus far with the cold infiltrating against disrupting lp at 192. UKMO, GFS and GEM not interested however.

[SMU]

Stella UKMO & ECM this morning -

both identical at 96/120/144

undercut city !!!

lets keep it simple - 

- trough disruption at 120 /144

- undercutter 144/168

 

s

[Cheshire Freeze]

3 minutes ago, THE CHOSEN ONE said:

Stella UKMO & ECM this morning -

both identical at 96/120/144

undercut city !!!

lets keep it simple - 

- trough disruption at 120 /144

- undercutter 144/168

 

s

216 hrs, ECM- Feb '96?

[IDO]

This has always been about getting the undercut nailed as early as possible, due to the block not being a standing anomaly, more of a mobile feature. The GEM for instance has two failed attempts at an undercut and it is on the third attempt there is success, but of course by then (D8) the heights have been shoved NE/E by the vortex lobe (failed trigger LP systems) in the Atlantic trough (too much energy):

GEM    GFS D7:  

^^^GFS around the same time and again its the third trigger low that gets the undercut, but again heights are only sufficient to push the jet further south. As Mucka said yesterday the easterly is pretty much a lost cause and its just a change of pattern from the different tracking of the polar jet and how much trough disruption we can get to keep those uppers cold rather than warmed out. Looking at the GEFS it does appear that the vortex lobe is too strong and will pass close to the UK, some members disrupt but many just bring significant rainfall:

    Pattern change to cooler, more seasonal upper flow: 

UKMO:   ECM:  D8: 

UKMO & ECM going with the undercut of the second LP so maybe catch some of that cold as a as the undercut is earlier than the other models. Though at over a week away I wouldn't be banking that just yet. But again better from the ECM, D8-10, more trough disruption. Though I consistently ignore that range for the ECM as it usually has the OP in the coldest cluster even when there is no trend!

The CFS week 2 and week 3 ties in with the GFS output, looks like the wet weather will continue but in a cooler flow. The w3 and w4 anomalies keep an Atlantic anomaly so more wind, rain but maybe less stormy. 

CFS 1 +2  CFS w3 & w4: 

So we are still at loggerheads as to whether we can get a cold spell from the models within a general westerly pattern with the heights to our NE. Euros -v- N.American's model wise. Maybe an answer tonight?

[london and south east kent]

Hi all looks like same old story with more wet weather to come next week more floods to come but I do see the pattern is slowly on the  change in lower  pressure to the south and much much colder to the east we won't just go in to a easterly over night the pattern is slowly on the change the cold will come soon 

[knocker]

Rather overpass than undercut

Chart weatherbell

[knocker]

Should improve the skiing in Europe with high PW values associated with a persistent jet.

[Man With Beard]

Ummmmm ... an even closer call this morning as to whether the cold pool will get this far west. So many failed attempts from the Atlantic to join up before one finally sticks at T168. All the while, the block is slipping further and further north. The undercut on ECM looks like Gordon Banks great save from Pele i.e. a great last ditch save of a lost cause. We need Scandi heights to be in less of a hurry to clear at around T96/T120 - still time for that.

Maybe it's good to remember where we've come from - just 4/5 days ago, only a few of us were calling for a pattern change - most were still seeing a continuation of mild. Now, I'd say the pattern change is almost secured in terms of less mild, but we're now possibly getting even more than was bargained for by getting under the polar front. 

Considering the flooding situation though, this is bizarrely one situation where a freeze would be more welcome than the rainy option - the further south the undercutting lows can get, the more welcome for northern areas!

 

[Whether Idle]

Does anyone have a link to the ECM120 postage stamps?

[Snowmad79]

After a washout that has been around for what seems like an eternity, we finally seem to be on the cusp of a proper winter blast. I say on the cusp as the heavy band off ppn being fed up from the southwest may push into the north sea before it hits the block and stalls giving a good dumping over the ocean whilst we continue get a drenching.

Obviously the ECM etc at 168hr would pull in some colder but at the moment it doesn't look like a pattern with longevity. Good to finally see some sort of change from the barrage of mild and sopping wet weather we have all had in recent months.

[northwestsnow]

13 hours ago, Carlrg said:

 

Excellent ECM this morning-

http://www.wetterzentrale.de/pics/Recm1201.html

http://www.wetterzentrale.de/pics/Recm1441.html

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

http://www.wetterzentrale.de/pics/Recm1921.html

Showing trough disruption as the block forces the jet SE into Europa.

Snow potential across the UK as last !!!

On the other side of the coin GFS is not great.

[nick sussex]

34 minutes ago, Whether Idle said:

Does anyone have a link to the ECM120 postage stamps?

Here you go:

http://old.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa%21168%21pop%21od%21enfo%21enplot%212009112700%21%21

Still a lot of uncertainty around that time, any showing the troughing positively tilted to the west will likely push too much energy over the top. This looks very much like a battle between operational run versus ensembles. At some point one will give in , lets hope its the ensembles.

[Ali1977]

Unfortunately but as expected signals of cold are slowly being dropped, ECM and UKMO look ok but won't deliver to the UK as a whole, maybe far NE. GFS looks poor throughout, and I feel this may be nearer the correct modelling than the others - and more inline with the METO.

Edited December 28, 2015 by Ali1977

[northwestsnow]

13 hours ago, Carlrg said:

 

Ali ECM is showing snow across much of the Uk this morning.

[shaky]

Doesnt take much for the gfs to show what ecm is showing!!lets hope it shows an undercutter next run!!ukmo and ecm similar at 144 hours!!could do with that low slightly less deep to the west though!!

[nick sussex]

2 minutes ago, Ali1977 said:

Unfortunately but as expected signals of cold are slowly being dropped, ECM and UKMO look ok but won't deliver to the UK as a whole, maybe far NE. GFS looks poor throughout, and I feel this may be nearer the correct modelling than the others - and more inline with the METO.

It was always unlikely that the deep cold pool would have a direct hit on the UK as the block is more based over Russia however you don't need that to get snow and the surface layer will be much colder than the 850's would suggest as you'll bring in lower dew points and temps from central Europe. The ECM forecasts max temps for Amsterdam next Monday -1c, Tuesday -5c.

You'd only need that deeper cold if you wanted the convective type easterly and there   hasn't been a strong signal for this. At this point I'd be more worried about getting that low to head se at T168hrs.