Model Output Discussion 29th December - Into mid-Winter.

[A Frayed Knot]

Reminder to us all 'Stick to FAX CHART'S ... Naff Computer Models ' they are Robots '''' Said it many a time . You all love the Garden Path full of PUFF !!!

Never ever learn ...

it's all Computer ..

Love .

[Daniel*]

Looking at the London ENS it does appear the GFS op was overly progressive definitely more legs in our cold period I'm thinking 5 days maximum but this is clearly subject to change, the best chance of snow thus far nationwide coming up you never know when it'll be the last, probably evading knocker country!...in deepest darkest FI some coldie interest probably meaningless at this stage, 20% of the perbs have +ve heights to the N/NE. 

Edited January 6, 2017 by Changing Skies

[That ECM]

What has been suggested for awhile now is fairly strong NW flow with uppers that would be cold enough for snow in favourable areas from about T144 onwards. Ukmo this morning t144 is positioned to bring this as is the gfs. Looking through each perb all but one to various degrees are suggesting this. When and to what extent will depend on where the high positions it's self.

 

From there onwards is very unclear imo and most options are on the table. FWIW I would punt at a glancing NW and the HP having to much influence for the opportunity to have a proper easterly for us further down the line. Time will tell as always.

Edited January 6, 2017 by That ECM

[knocker]

Will skip commenting on the overall pattern this morning as there is little change and everyone should be pretty familiar with it so it's just a matter of how the GFS is handling the more detailed evolution.

Monday has a low tracking east north of Scotland with associated fronts tracking SE across the UK bringing some light rain to most.with average temps. Post the passage of the fronts a showery NW airstream (Showers more likely in the North) with a bit of a squeeze between the HP to the SW and LP to the NE. Then on Thursday a perturbation forms in mid Atlantic which seems to be a combination of the upper trough tracking east from the vortex and energy sneaking up from out low to the south. It was from this development yesterday that it conjured up some explosive cyclogenisis.

It doesn't do that on this occasion but does herald the well sign posted wintry spell as it runs it rapidly east, traversing the UK and is in the Baltic by Friday where it has phased in with the deep upper trough just to the NE. This briefly plunges the UK into a much cooler NW/N airstream which could well bring some significant snowfalls on high ground in Scotland and the north of England.

The upper trough quite quickly moves away SE leaving the Azores HP to push NE once more leaving the UK in a light W/NW showery airstream with temps for a time well below average so some of the showers will be quite wintry. After that....................best left for now although dog's dinner springs to mind.

Which all in all fits in okay with this morning's anomaly

Edited January 6, 2017 by knocker

[AWD]

The main message from the 0z GEFS is make the most of next weekends polar NW/NNW airstream;

Near unanimous support for a return to average fayre thereafter.  Can see all the cold/snow fanatics from southern England frantically booking a weekend away up north next weekend.  Lol.

[Seasonality]

Just for fun of course. But a cold FI for much of Europe. 

[knocker]

[winterof79]

Nice chart from ECM.

 

Edited January 6, 2017 by winterof79

[Seasonality]

5 minutes ago, knocker said:

So does this show that naughty Azores high back in business with a Russian High and colder trough into Europe? Maybe some similarities to 00z GFS FI?

[knocker]

4 minutes ago, Seasonality said:

So does this show that naughty Azores high back in business with a Russian High and colder trough into Europe? Maybe some similarities to 00z GFS FI?

It does indeed show that with general low pressure Siberia/Aleutians and Alaskan ridge into the Arctic.

[knocker]

The ecm has a different take towards the end of the run. It has a depression southern Greenland at T168 which tracks E/SE on the jet to be over Central Scotland by T216. which may well bring some snow to high ground in the north. The Azores ridges NE in it's wake.

Edited January 6, 2017 by knocker

[bluearmy]

ECM op days 8/10 shows a differing polar profile to expected direction of travel with AO staying positive. All ens guidance has been for -1/-2 post Jan 13 for at least four/ five days so as per yesterday's post day 7/8 offering, I will not be bothering with the op until the ens are out and the spreads will be where my attention is placed. safe to say that not unexpected for the means to be skewed towards the theme of the op so a neutral AO likely 

[mb018538]

ECM is poor this morning - too much energy and a flat profile. A brief day of -5 850s before the slightly milder stuff makes its presence felt again. Detail too hard to pin down still.

[Man With Beard]

So yesterday's ECM was on the optimistic side of the ensembles, and this morning it is slightly on the pessimistic side. General theme isn't really that different though - short colder blasts with main risk of snow for the north

[MR EXTREMES]

so once again before the 144 time frame most of the models are backing away from even mid lat blocking,

more towards captain sw post last night.

 

so brief northerly before the next low pressure system sweeps in from the west.

so no north or northeast flow looks likely, the met office ideas on northerly and north westerly looks likely, before the azores heights nudge in from the south west.

these heights cant go many places as we have lower heights to our east north and northwest most importantly around greenland where the annoying vortex remains dominant.

we really need help from the stratosphere to really disrupt a dominant vortex.

as blue has suggested very weak signal in regards to ao,

but likely to remain slighly positive and the nao likely to be steadly rising to positive.

but this does not mean winter is over and if i were to punt for a better chance of real blocking id say end of jan going into feb possibly even march when the vortex starts to run out of steam.

last winter see things change around april after a warming event in march although ive wrote of most of jan, already based solely on the energy and location of the polar vortex!,

also add the west qbo, very boring mjo signals, and the north pacific monster ridge id be inclined to believe theres more against hlb similar to last year only that low pressure has not been the dominating as much as last year.

the models certainly find it hard to model these set ups but broadly speaking i cant really find any straws to clutch last night ecm had better mid lat block coming close to high lat block but once again looking likely it was a over excited run.

i would not be suprised to see the northerly downgraded or pushed east in future runs.

 

[bluearmy]

Btw, not enthused about the ec46 now I can see the whole picture

maybe that's a good thing for coldies! 

[blizzard81]

I think Tamara's excellent post from last night will be ringing in many people's ears this morning.  I expect the ecm ens to flip to the mild side again and that's where they will stay.  The nina base state has scuppered any chances of prolonged cold this season. Just think winter 10/11 but without the cold December. 

[blizzard81]

17 minutes ago, bluearmy said:

Btw, not enthused about the ec46 now I can see the whole picture

maybe that's a good thing for coldies! 

The ec46 has been shockingly bad this winter.  In same camp as the cfs.

[ArHu3]

16 minutes ago, bluearmy said:

Btw, not enthused about the ec46 now I can see the whole picture

maybe that's a good thing for coldies! 

The devil is in the details, it was right on the grand scale of global anomalies for January and December but details proved to be fatal for cold 

[shaky]

The 00z runs seem to reduce amplification whereas the 12z runs seem to increase it and therefore slightly better runs!!please tell me am not the only one that has noticed this!!

[bluearmy]

2 minutes ago, blizzard81 said:

The ec46 has been shockingly bad this winter.  In same camp as the cfs.

Thats a bit harsh !!

to be fair, it has never peddled zonality thus far and we have not seen zonality which would be the norm.

[blizzard81]

2 minutes ago, bluearmy said:

Thats a bit harsh !!

to be fair, it has never peddled zonality thus far and we have not seen zonality which would be the norm.

Maybe so but it was completely wrong with the high latitude blocking it steadfastly kept touting. It never forecast the mid latitude block that we got stuck with. 

[MR EXTREMES]

the only straw i could find that maybe throwing models into a frenzy is the vortex displacement shown on the gfs although im not altogether confident in vortex disruption.

[Frosty.]

The latest models are still showing a colder shot with snow potential later next week, especially for the north. The Ecm 00z indicates further reloads from the NW beyond day 10..following the upcoming nondescript mildish weekend it looks increasingly interesting as we go through next week with snow likely to be in the forecast at times which would be better than what we have seen so far this winter by a distance!

Edited January 6, 2017 by Frosty.

[Alekos]

39 minutes ago, bluearmy said:

Btw, not enthused about the ec46 now I can see the whole picture

maybe that's a good thing for coldies! 

How is it looking for Greece ? ! I'm thinking the trend is for strong Northern jet and milder for NW Europe ?