Model output discussion - 1st December onwards

[Liam J]

Certainly not as good as previous ECM runs, here comes the Atlantic? 

[knocker]

Taking the gfs this morning the main concern over the immediate future is how much rain will be deposited from the systems traversing the country starting with Frank tomorrow. After Frank another system is due over the weekend before a low is looking set to run across central southern England at the beginning of next week. Looking further ahead into the Land of Oz a deep depression is set to hit western Scotland courtesy of a strong jet but obviously there will be some adjustments in the interim.

Chart weatherbell

[Man With Beard]

Close but no cigar on this run.

Two things to note though. First, All models now show a nasty storm at T216. Second - the PV is in serious trouble, being displaced all over the NH. Who saw that coming?!

[Liam J]

Temps look like coming back down to where they should be for the time of year at least maybe a bit below, coldest air looks like coming from the west in PM shots, wouldn't call it a cold spell although after recent mild weeks it will feel colder.. We appear to have taken a step backwards of sorts... And people were moaning that the Met Office weren't jumping on the cold bandwagon. But it wouldn't take much adjustment to pull much colder air towards the UK... In the short term rain, wind & further flooding misery likely unfortunately. 

Edited December 29, 2015 by *Sub*Zero*

[northwestsnow]

UKMO 144 pick of the 00z runs-

http://www.wetterzentrale.de/pics/Rukm1441.html

 

[knocker]

Just to add to my post above a brief summary of the ecm run.

Very unsettled with a few periods of wet and windy weather traversing the country. Any snow confined to Scotland apart from a flurrry at the end over the N. of England and the mountains in Wales. Temps varying a little below and above but generally average. At the end of the run the cold pool to the east is situated over western Russia.

[northwestsnow]

4 minutes ago, knocker said:

Just to add to my post above a brief summary of the ecm run.

Very unsettled with a few periods of wet and windy weather traversing the country. Any snow confined to Scotland apart from a flurrry at the end over the N. of England and the mountains in Wales. Temps varying a little below and above but generally average. At the end of the run the cold pool to the east is situated over western Russia.

Morning knocker, i was thinking the ECM might still produce for snow for Northern England Scotland and perhaps Northern Ireland.

[northwestsnow]

4 minutes ago, *Sub*Zero* said:

Yes but negligible away from hills.

No denying thats a big downgrade on the snow chart Liam, all my eggs are going in the UKMO model basket

Edited December 29, 2015 by northwestsnow

[knocker]

4 minutes ago, northwestsnow said:

Morning knocker, i was thinking the ECM might still produce for snow for Northern England Scotland and perhaps Northern Ireland.

Morning nws. Yes it does indicate that in the latter part of the run but generally the Atlantic systems are pushing the colder air back so rain is the order of the day. The usual caveat that this just one run.

[carinthian]

Good Morning all, well I like the look of this chart from UKMO on a broader scale. Euro high looks like on the way out with a general fall of pressure over Western and Central Europe at long last. The Low to the West of The British Isles seems to be align a trough with NW/SE axis, which could produce a frontal battle zone . Higher pressure values holding across Northern Russia with a ridge out westward . Note the developing cold wave over Southern Sweden. All in all, certainly a drop in temperature, whether the developing set up produces snow, we cannot confirm on todays models, but will get close . Interesting to watch the models over the next few days.

C

[Timmytour]

1 hour ago, Man With Beard said:

ECM T144 - the cold pool has hit a disturbance over Norway which stops a clean westward progression.

If I'm not mistaken, that's a familiar theme of the past two winters we've had?

[Hotspur62]

Well to me the broad trend over last 24 hours across models is a case of close but no cigar for a UK wide cold spell, The High over Scandinavia although Strong seems to be furher East and the really cold uppers never really reach us in the UK staying a good 2-300 miles to the East of us.Also, as I mentioned yesterday the Lows are not sliding low enough to properly drag in the colder air from the East. As a result temps from the New year I think will be 6-9 Midlands Southwards and probably 3-6 Midlands northwards with places of elevation(200m upwards) having a stronger probability of seeing snow. I am just using past scenarios where things have been similar over last 3-4 years. Just a realistic call I think but the positive thing is we will hopefully have a -AO,the High is strong enough to have another go or two in the future,heights are dropping in the Med,the Jet seems to be diving slightly further Southwards and there is a much colder Continent to drag in colder air so all is not lost.

 

It is just a shame in times like this that our lovely little island is not about 300 miles futher East and a bit further North which would certainly cut out any margainivity!!

[NO LONGER POSTING]

Have to agree with the above posts the trend is to cooler conditions without this mild barmy temps but nothing of note unless you live up a mountain. The drivers are there but they just can't drive us into a proper cold spell. It wil be welcome non the less by many seeking something more wintry but we will have to wait a little longer for anything more widespread and substantial. Although things can and will change 

[Nick F]

I think many people in the north and west will be praying for high pressure rather than slow moving frontal battle zones - no signs of that. Rather disturbing seeing endless Atlantic lows piling in to the UK against the block to the NE. 8 day rainfall total from GFS for Cumbria of 75mm maybe a tad conservative, especially for high ground, many other western areas like Wales seeing far too much too.

In terms of better chances of tapping into deeper cold air tantalisingly close over Scandi/Baltic, really need to see height rises over the Norwegian Sea and a more southerly tracking jet to be sustained, join up of N Atlantic low heights and Scandi low heights developing from the cold pool would not be good. Still, don't think we are out of the game for some colder solutions further south quite yet ...

[shaky]

Just woke up and my god gotta say what a set of models!!!ukmo and ecm keep the undercut and gfs is slowly but surely getting dragged towards the euros aswell!!!steve murr is right looks like a snow event as early as 72-96 hours for some parts of the country!!!low sliding in and then disrupting over the uk!!!

[Cloud 10]

ECM ensemble mean at day 8 looking much better than the op. run with -4 uppers covering a fair chunk of the UK.

Op.run..  Ensemble mean..

 

Very encouraging longer range GEFS as well,with a negative  AO being advertised.

 

[bluearmy]

i missed a good conversation over the ec monthly etc last night. worth re reading if anyone missed it.  i have noted the high anomoly to our sw towards the end of week 2 on the ec eps and now the gefs come into some agreement. the search for winter has many directions this morning. early part of next week remains plausible across a swathe of the uk. the atlantic jet looks strong thereafter but the spreads on ecm havent quite given up on that being further south than currently modelled. what does seem clearer is that the blocking to our east will relax to allow the jet through but at what latitude and on what axis? 

so many conflicting signals but i agree with ed that the current most likely route to sustained  winter would come via retrogression of that high anomoly to our sw towards greenland. (high heights across the polar field to our north will be receptive to strong ridges from the mid latitudes). seems possible around mid jan.  EC monthly and paralell version offer some support here, as do the GEFS and ec eps.

Edited December 29, 2015 by bluearmy

[Nick F]

^^^ add to what @bluearmy mentions above, the 00z EPS control shows a mid-Atlantic ridge up though Greenland building days 10 -15.

Day 10 EPS mean indicating retrogression of +heights from Kara Sea to Greenland and generally  the polar area seeing +heights at 500mb  - bolstering the -AO signal, which looks good for us longer term.

I think the bitter cold easterly idea is out of favour, though was never really on the cards anyway, however, there remains the potential for cold enough air feeding west to bring some frontal snow to northern and perhaps central areas if the jet can adjust a little further south.

 

Edited December 29, 2015 by Nick F

[blizzard81]

48 minutes ago, bluearmy said:

i missed a good conversation over the ec monthly etc last night. worth re reading if anyone missed it.  i have noted the high anomoly to our sw towards the end of week 2 on the ec eps and now the gefs come into some agreement. the search for winter has many directions this morning. early part of next week remains plausible across a swathe of the uk. the atlantic jet looks strong thereafter but the spreads on ecm havent quite given up on that being further south than currently modelled. what does seem clearer is that the blocking to our east will relax to allow the jet through but at what latitude and on what axis? 

so many conflicting signals but i agree with ed that the current most likely route to sustained  winter would come via retrogression of that high anomoly to our sw towards greenland. (high heights across the polar field to our north will be receptive to strong ridges from the mid latitudes). seems possible around mid jan.  EC monthly and paralell version offer some support here, as do the GEFS and ec eps.

All well and good but our biggest problem will be that very persistent lobe of pv over north east canada. If anything it seems to strengthen yet again over time.

[blizzard81]

58 minutes ago, shaky said:

Just woke up and my god gotta say what a set of models!!!ukmo and ecm keep the undercut and gfs is slowly but surely getting dragged towards the euros aswell!!!steve murr is right looks like a snow event as early as 72-96 hours for some parts of the country!!!low sliding in and then disrupting over the uk!!!

The ecm op is a big but not surprising downgrade on previous runs. Ukmo looks good at 144.

[bluearmy]

5 minutes ago, blizzard81 said:

All well and good but our biggest problem will be that very persistent lobe of pv over north east canada. If anything it seems to strengthen yet again over time.

Or you could look at that as being our supply line of systems to be deflected underneath the developing blocking. you need something coming East to deliver precip to nw Europe and also to re supply any euro trough which is always essential to a sustained wintry pattern. 

in contrast to previous winters, I think the polar split upcoming will prevent energy seeping back across from the east Siberian vortex to bolster the Canadian for long enough if things are going to evolve to a decent winter pattern for our part of the NH.

of course, it could all end up in a mid lat block which would be great news for the saturated north of the UK. 

Edited December 29, 2015 by bluearmy

[I remember Atlantic 252]

1 hour ago, shaky said:

Just woke up and my god gotta say what a set of models!!!ukmo and ecm keep the undercut and gfs is slowly but surely getting dragged towards the euros aswell!!!steve murr is right looks like a snow event as early as 72-96 hours for some parts of the country!!!low sliding in and then disrupting over the uk!!!

Not really an undercut on ECM, if anything ECM has trended towards GFS, UKMO though shows an undercut but not full one

[shaky]

Gfs trending towarda the ukmo and ecm again regarding that shortwave at 90 hours!!slightly further south and west!!!

[blizzard81]

2 minutes ago, bluearmy said:

Or you could look at that as being our supply line of systems to be deflected underneath the developing blocking. you need something coming East to deliver precip to nw Europe and also to re supply any euro trough which is always essential to a sustained wintry pattern. 

As long as they undercut, otherwise it's just more wet, stormy weather. This is what I fear as heights remain relatively high over southern europe.

[Weathizard]

1 hour ago, Cloud 10 said:

ECM ensemble mean at day 8 looking much better than the op. run with -4 uppers covering a fair chunk of the UK.

Op.run..  Ensemble mean..

 

Very encouraging longer range GEFS as well,with a negative  AO being advertised.

 

A quite massive difference between that and the 00z GFS ensemble suite mean, surprising for two ensemble suites to be so different, shows the volatility of the situation I guess.

 

 

Edited December 29, 2015 by Weathizard