Model Output Discussion 4th Dec.2013-12z onwards.

[Captain Shortwave]

At day 7/8, the ECM cuts off the deep Atlantic trough forcing a cut off low towards the Canaries, this results in a strong flat west/south west jet stream across the Atlantic. Unfortunately that is a further nail in the coffin which goes with the residual energy over northern Russia/Finland pointed out yesterday. Prognosis for the next fortnight at the moment looks very poor to be honest. But it doesn't mean we will see out December like this.

The GEM evolution looks highly suspect with respect to the low near Greenland at just 4/5 days out, the low simply hangs around Greenland for no real reason. It doesn't look right to me* and of course this is crucial to allowing a more northerly push of the ridge to give heights further north.

* Just because I say it doesn't look right, does not mean that this is correct and by some miracale we will be in a frigid easterly in 10 days time 

Edited December 4, 2013 by Captain shortwave

[Mucka]

i'm talking about the z500 spreads mucka. wherever the 00z had the clustering and jet energy at day 10, the 12z op followed.  too late to show you now as the 12z has updated the 00z charts.

 

Fair enough. I don't like the 12z mean so I guess the postage stamps (are you getting them?) are much the same as this morning with little Easterly influence?

The 12z Op does pretty much follow the 12z mean as well so fair does, I'm still expecting the Op to reflect milder in the graphs though from day 8.

What would be nice is to see a split that results in that mean with at least a cold cluster, (say 20% or so)

Edited December 4, 2013 by Mucka

[TSNWK]

So the ECM 12z suggests to me that op will not be the mild outlier it was on the previous 2 runs, another signal that we are about to enter a long mild dry period after this chilly snap and possible inversion chill in the southeast early next week.

I would also expect the next ECM 32 update to flip mild on Friday, due to the trends over the last 36 hours or so. A neutral metoffice update on Thursday continuing the back away from the postive update for coldies we saw on Monday. GFS has never really be up for the easterly..

We are in a bit of pickle at the moment coldies.. We are trending in the wrong direction, getting further away from decent cold.

GEM this is your moment to shine

Edited December 4, 2013 by TSNWK

[tinybill]

i  know if  fantasy  world the cold  lovers  are dreaming  if it carry on could it  be  white  on the  big  day who knows

Edited December 4, 2013 by tinybill

[bluearmy]

Fair enough. I don't like the 12z mean so I guess the postage stamps (are you getting them?) are much the same as this morning with little Easterly influence?

The 12z Op does pretty much follow the 12z mean as well so fair does, I'm still expecting the Op to reflect milder in the graphs though from day 8.

What would be nice is to see a split that results in that mean with at least a cold cluster, (say 20% or so)

 

nope - you have to spend a small fortune to get the postage stamps (or at least work for an organisation that does!).

 

we are seeing variations on a theme. there was never a strong suggestion that the ridge would get far enough north to provoke deep cold by mid month. we are just seeing options whereby the northern arm is reinvigorated as less energy heads into the southern arm. the fact that the ridge is suriviving just to our east rather than sinking away is testament to its strength.

[bobbydog]

GEM pertubation 12 please!

 

[Lake District Blizzard]

The biggest positive to take from the models today is that it is much better to have these synoptics  in the first half of december, than have them popping up after the new year in January or February.

 

If it was a choice between mild high pressure or Atlantic depression after depression with lashings of wind, rain and flooding, that is typical of early december i think id take the high pressure every time.

 

Id like to see something like the GFS 12z FI develop around the 20th with a nice cold frosty high pressure sat over the uk, giving way to a north easterly blast just in time for Christmas 

Edited December 4, 2013 by Lake District Blizzard

[phil nw.]

The later naef's ht anomalies keep that +ve anomaly around the UK/W.Europe right out to the end of the run.

The high wanders towards Denmark by day 9-10 and the ECM set also continue to show a robust block just to our east at day 10.

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

 

Looks like a blocked setup to me with a quiet Atlantic with the jet split in mid-Atlantic going over and under the Euro block which is holding fast.

http://modeles.meteociel.fr/modeles/gfs/runs/2013120412/gfsnh-5-192.png?12

 

It does suggest that fears of zonality kicking in are still premature.

[legritter]

Well nothing on tonights ECM for coldies ,unless it as the position of the high in its last 3 frames totally wrong and the high finishes up much further north .And at this range other possibilitys are possible .GFS not on our side but i half expect this to flip pretty soon ,but in what direction . GEM Model well and truly showing us some promise and hopefully its smelling something .UK MET as we dont get to see longer range charts are i think toying with a possible change in about 10 days time ,but you can only gleen this from its updated further outlooks . some posts tonight talking of christmas well 21 days away thats 42 runs of ECM and MET  Office and 84runs of GFS,,and of course GEM and many more .Three weeks time could be totally different .The  Polar vortex could be totally in another state with the Atlantic Oscillation going Negative ,we are in a very good position gang its only Day 4 of winter with many changes to come ,they could all stack up against us but equally be our friend .never give up the chase BUT be patient .Crack open a STella .cheers .

[Mapantz]

The biggest positive to take from the models today is that it is much better to have these synoptics  in the first half of december, than have them popping up after the new year in January or February.

I can understand that sentiment but who's to say that they won't continue like that until March? I find it tricky to believe that getting a certain synoptic out of the way now will help produce better synoptics further down the road. Of course, i could be wrong, there may well be some scientific data that could back that up :lol:

[Cloud 10]

GEM pertubation 12 please!

 

 

Aha! The GEM ensemble members are now available to view individually and also in 

Northern Hemisphere view.

 

Meteociel - Cartes Ensemble GEM (GENS GEM / CMC ENS)

 

 

Many thanks Sylvain.

[Gibby]

Good evening everyone. Here is tonight's look at the 12 noon outputs of the big 5 weather modules and what they mean for us at the surface over the coming few weeks from today Wednesday December 4th 2013.

 

All models show a rapidly deepening depression moving East to the North of Scotland while Southern Britain lies under a weak ridge of High pressure tonight. Through the night winds increase markedly over Scotland then Northern England with severe gales and storm force gusts in places. An area of rain will move South too, heavy and squally briefly before clearer and colder weather with a continuation of severe gales and developing wintry showers of sleet or snow across Scotland by the end of the day. England and Wales will also see winds increase with a weak band of rain towards the end of tomorrow, however winds are not expected to be troublesome here with rainfall at a minimum too. Thereafter a cold and dry Friday once remaining wintry showers clear the NE leads into a milder trend over the weekend and start of next week as High pressure crosses ESE over the South and away to NW Europe where is it looks like settling for some considerable time.

 

GFS tonight then shows little change to these synoptics for virtually the remainder of the run with SSW winds blowing up across the UK with the mildest conditions over the North and West while Southern and Eastern areas stay fine and possibly cloudy but less mild then further NW.

 

UKMO tonight closes it's run with High pressure close to the Netherlands with a light Southerly feed over the UK. All areas look like staying dry and relatively mild in any brighter spells and in the lee of high ground to the South. There is still the risk of patchy frost and fog at night across the SE in particular.

 

GEM shows High pressure building over Scandinavia towards the middle and end to next week before High pressure transfers to Greenland swamping the UK in colder winds from Europe with some clearer air making for some frost at night in shelter from the SE wind.

 

NAVGEM shows High pressure towards Central Europe with a ridge towards the UK and the Jet Stream roaring over the top of the High over Scandinavia. This keeps many areas fine and dry with a lot of cloud and average temperatures or above for all, coldest in the SE.

 

ECM tonight shows a sobering though for cold lovers tonight as it shows High pressure covering most of mainland Europe with dry weather extending across much of he UK too. With a broad SW flow temperatures look mild or very mild for some with occasional rain at times possible towards the NW at times.

 

The GFS Ensembles show good support for very much warmer conditions aloft next week and probably beyond. At the surface it may also be mild as South or SW winds mix the air out to bring some of that mild air to all at times. As usual at the end of the run natural variability between various solutions ensues with no definitive trend to be drawn from that range.

 

The Jet Stream tonight shows the flow moving NE to the NW of the British Isles after the temporary diversion SE down the North Sea for the next 24-48hrs. It shows very little sign of deviating from this location for the foreseeable future tonight.

 

In Summary tonight leaving GEM's operational fanatics aside all models support a sustained period of potentially mild and benign weather for the foreseeable future once the gales and coldness of the next few days dissolves away. High pressure looks destined to become slow moving to the SE of Britain with South or SW winds driving mild and cloudy weather from the East Atlantic over Northern and Western areas at least. Southern and Eastern parts may also be mild at times though winds from a more SE direction at times could direct some rather colder air across at the surface with the risk of overnight fog and frost patches. Amounts of rain over the two weeks looks small.

[R.P. McMurphy]

GEM pertubation 12 please!

 

 

White cold christmas anyone?

[Summer Sun]

As Gibby pointed out the next 2 weeks has very little rain some parts of the south could go 2 weeks without any

 

[fergieweather]

So is the GEM not particulaly facvoured because it is the wrong set up or because its evolution is just too fast? I thought i read that high pressure to the North/East was a favoured solution by the met yesterday (EC 32 solution too) although this was around day 15? Sorry if i picked the wrong end of the stick up somehow.

No, they said we don't discount GEM solution but we don't favour it given ensembles going other direction. 12Z EC will merely bolster that view. Monday EC32 is superceded by Fri update, but it's blocked signal later Dec isn't supported by some other products & thus a dichotomy of possible outcomes by then has emerged past 24hrs. Key lesson here isn't to get hung-up on this stuff churned-out post T+144 too much or get suckered into hopecasting, especially anyone who harbours affection for specific WX type. It's not worth the stress/coronary. Christmas will happen, be it mild or chilly.

[R.P. McMurphy]

As Gibby pointed out the next 2 weeks has very little rain some parts of the south could go 2 weeks without any

 

 

Come on Gav, a precipitation forecast for the next 2 weeks is about as much use as a strange gas in a spacesuit..... It stinks.

Edited December 4, 2013 by Glenn W
hidden inappropiate word-guess

[Summer Sun]

Come on Gav, a precipitation forecast for the next 2 weeks is about as much use as a **** in a spacesuit..... It stinks.

 

The ensemble supports a very dry outlook for the south, so its not out the question

 

[Ali1977]

High pressure much further east giving slight continental feed, slightly cooler...

Better run coming I think

Edited December 4, 2013 by Ali1977

[Ali1977]

Cold air is into France and Belgium at T156, that was no where near on the 12z

[cold snap]

Could be a pub run 18z special here .

High better positioned at 156 hours already ,completely different to 12z

[Barry12]

18z vs 12z

 

 

 

Much better

[Ali1977]

False alarm I maybe, looks like high is starting to sink again....definitely changes ahead ref that high location I think!!!

[I remember Atlantic 252]

Yes the 18Z is better, only 3C max with continental air next Wed (midlands), just hope we can draw clear skies in from the SE

[TSNWK]

18z vs 12z

 

 

 

Much better

Sorry cant see it. Yep things looked a bit better around 120 - 144 with stronger ridiging north east. But then the high deflated south again..

[Panayiotis]

Yes a much better 18z with the low further south in the Atlantic which has a slight negative tilt. Seems good for day 10, we shall see...