Model output discussion 25th Jan - The final third of winter beckons..

[Dennis]

frozen times ahead

[Wayneywoo]

It's only a matter or time but you can see with every run the Scandinavian High is driving for Greenland...

[MR EXTREMES]

1 minute ago, Wayneywoo said:

It's only a matter or time but you can see with every run the Scandinavian High is driving for Greenland...

Absolutely agree I think the ecm has been awful gfs started awful but got better ecm is downgrade upgrade each run.

But ukmo is held firm for days now and also retrograde is a strong possibility beyond the weekend.

Best charts to watch over the coming days would be uk met fax charts.

[warrenb]

Scandi blocks are a nightmare to model, and are always broken down to quickly, think about it, the models are having to deal with a complete reversal of pattern.

Always have been a problem, remember the 80's when the forecast for these was difficult at best. You see all the forecasts on youtube, but these are when it is already in place and snow is falling.

Once in place they are very difficult to breakdown and tend to meander around. Signs are very very good in the models at the moment.

[Wayneywoo]

I don't know what it is with the GFS 06z but it looks like it's going awry again after say 100hrs ish.

Waiting for the more knowledgeable to comment...

[winterof79]

In the beginning 1043MB

The remnants of Tuesdays rain band being sent packing back to the UK with its tail between its legs

 

 

 

Lovely orientation at 1050MB which is higher than any model is projecting

Edited February 6, 2017 by winterof79

[Gustywind]

7 minutes ago, Wayneywoo said:

I don't know what it is with the GFS 06z but it looks like it's going awry again after say 100hrs ish.

Waiting for the more knowledgeable to comment...

Looks ok to me, slightly higher pressure towards Iceland than the 0z at t120, block further west. 

Light snow developing Sat PM as cold blob moves in, widespread -8s upper air.

Edited February 6, 2017 by Gustywind

[cheshire snow]

Just now, Connor Bailey Degnan said:

If you're a cold fan, end of this week should be decent enough for you. However if you're a snow fan, and you like proper snow, not little grains, then they're isn't much to be excited about, at least in the short term. May be upgrades to come.

Spot on IMO Connor

certainly turning a lot colder,with some snow flurries or light snow showers especially for Eastern areas,however widespread snow is certainly not in the forecast YET, however the longer the cold stays in place I do feel there will be opportunities for more in the way of the white stuff.

C.S

[winterof79]

Lovely kink in the bitter  flow at 138Z

Edited February 6, 2017 by winterof79

[stodge]

Morning all

I last commented on here last Tuesday or Wednesday and I said then that IF we were still in the game in terms of the hunt for a pattern change by Monday morning, it would be time to get more excited.

It's been a roller coaster few days topped off by last evening's ECM 12Z OP which certainly set the feline among the pigeons.

This morning, however, and thankfully for most people's sanity, order seems to have been restored and for fans of cold it looks a solid outlook though for fans of snow less so.

As Mr 1962-63 has reported, it would be unwise to under-estimate the strength of the cold block advancing west into Scandinavia yet progressive (or should that be over-progressive) modelling can do that. As we saw just two or three weeks ago, the "breakdown" from the last European MLB was pushed back four or five days from initial modelling to reality.

I then argued for 14 days of milder Atlantic-dominated weather.

I was wrong - well, partially. Some of the blowtorch SW'ly charts presented by GFS failed to materialise as, to be fair, did some of the storm-laden outlooks from some of the other models. It's not been that mild or that stormy (especially in the SE) - there has been rain but not enough to set against what has been an unusually dry winter so far.

So, what now ?

For fans of cold (as distinct from snow), the ESE'ly set up is as good as it gets. The minimum fetch across the North Sea for frigid air accentuates the cold and is much better for sunny days than the traditional E or NE airflow which picks up cloud from the warmer North Sea. The forward energy in the northern arm remains a problem but as long as the core of HP remains above 50 degrees North, the air flow will remain nice and cold.

Blocks don't last forever - the Scandinavian blocks usually go one of three ways - one, they retreat back East into Eurasia, two, they sink South and three, they retrogress West to the North of the British Isles and then to Greenland.  The model output is offering the possibility of a Northward ridging Azores HP setting up around Iceland and that would certainly maintain the cold blocked regime.

GFS in FI has sniffed at option three on a few occasions and that remains the holy grail for cold/snow fans. Whether we will see enough retrogression to allow the trough to drop through the British Isles and re-enforce the E'ly flow remains to be seen but that would be the ideal scenario for snow fans. I must confess Option 2 would be my favourite at this stage as strat displacement needs to be just right to keep the Atlantic at bay.

As for the models, UKMO has, IMHO, led the way this winter and has been solid throughout the approach to this new cold spell. This morning's output suggests Option 2 (see above) but it's very early to be dogmatic about the weekend and beyond. GFS has, with the odd flip and flop, done very well in general terms and this morning's 00Z output was more eye candy for cold and snow fans. ECM hasn't been so supportive of a long cold spell and has played Option 2 strongly in the past 24-36 hours. As with others, I've struggled with elements of the ECM evolution but it cannot and must not be dismissed out of hand. GEM has played a good hand as well - it's a model which never goes overboard with blocking but has been consistent.

 

[frosty ground]

Features starting to appear now on the models now..... Northern England in this case.

[Iceberg]

Gfs looks very good, more importantly the small wave that develops for Sunday will imho develop into a meso low at it enters the t96-72 timeframe with warm sector and cold sector. The warm sector should still be cold enough for snow but I can see this giving 2-8 inchs due to the low progression and infeed of moisture from the North Sea. 

 

[Ali1977]

5 minutes ago, cheshire snow said:

Spot on IMO Connor

certainly turning a lot colder,with some snow flurries or light snow showers especially for Eastern areas,however widespread snow is certainly not in the forecast YET, however the longer the cold stays in place I do feel there will be opportunities for more in the way of the white stuff.

C.S

Widespread snow looks a possibility onSubday according to GFS - and it would lie wherever it falls in sub freezing temps 

Edited February 6, 2017 by Ali1977

[Gustywind]

Light to moderate snow continuing for many during Sunday, bitterly cold still. Another area of low heights moving into E Europe under the block at t150, helping to sustain the easterly flow.

[snowray]

Full agreement with UKMO now on the 06z out to T150, trough moving west with some heavier snow showers for much of the country.

[sparky1972]

just a quick question before the day get busy on here, i am reading alot about potential cold developing from wednesday but all i can see from a local forecast is for temps to rise, from 2c to 5c by sunday on the metoffice site, are they seeing something different using there own model?

[Ali1977]

4 minutes ago, snowray said:

Full agreement with UKMO now on the 06z out to T150, trough moving west with some heavier snow showers for much of the country.

From here look at the pressure building over Greenland - this looks good for further down the line 

5 frames later and PV has gone - big surface HP building

Edited February 6, 2017 by Ali1977

[winterof79]

[cheshire snow]

Just now, Ali1977 said:

Widespread snow looks a possibility onSubday according to GFS - and it would lie wherever it falls in sub freezing temps 

Let me be more precise the cold spell starts Wednesday I was talking about the first 96 hours or so anything after Saturday is pure FI at the moment,should have been more precise  in my post apologies 

C.S

[Ali1977]

Greeny high and Booming FI on its way 

[numbnutts(uk)]

new tweet from mr f .

Ian Fergusson ‏@fergieweather  59m59 minutes ago

More

W COUNTRY By Thurs on, colder air spreads W: mostly dry; a few snow flurries at times; a low risk snow showers appear more widely at weekend

[TEITS]

7 minutes ago, sparky1972 said:

just a quick question before the day get busy on here, i am reading alot about potential cold developing from wednesday but all i can see from a local forecast is for temps to rise, from 2c to 5c by sunday on the metoffice site, are they seeing something different using there own model?

Possible if the flow veers from a E,ly to a NE/ENE,ly. The temp rise occurs due to the warming effect though the wash. Seen this occur many times.

[Weathizard]

The scandi high is absolutely huge, almost too big for us to get the best benefits! That being said I think it's best anything outside of day 5 is taken with a pinch of salt, this includes the ENS which I think in such complex setups are about as useful as a chocolate fireguard.

[Ice Day]

At 192, after a brief 'warm up' (not warm!), the winds a starting to swing more ESE bringing the cold pool in Europe our way again. As Ali said, heights building up towards Greenland could lead to some FI shenanigans!

 

[terrier]

Well well well the gfs06z is a cracker cold right from t60. Snow showers packing into eastern counties. Think once the cold gets in it's gonna take some shifting. And once the Atlantic does try to make inroads could be some big snowfalls for western areas.