Model Discussion 12Z 25/02/13

[phil nw.]

A new thread for the 12z runs and possibly the last Winter one.

It still looking rather cold for the rest of this week with the Scandinavian High gradually moving towards the UK by the end of the week maintaining the quiet and settled theme.

I wonder what pattern the models will settle on for the beginning of March with energy split north and south it`s finely balanced and with cold air lurking just to our north and east Winter could still bite back.

Usual requests for politeness and on topic posts please folks.

Anyway continue below.

Edited February 25, 2013 by phil nw.

[phil nw.]

As expected no real change at T120hrs on the 12Z GFS

http://cdn.nwstatic....120/h500slp.png

The high over the UK nicely sandwiched between the Atlantic trough to our south west and the Scandinavian trough.

Settled,light winds,daytime temps still single figures with night frosts where skies clear.

[Purga]

I wonder what pattern the models will settle on for the beginning of March

Well before 12z fires up - it would be nice to see p10 of the 06z be the pattern that develops

[phil nw.]

Little doubt about the setup for this week now with both GFS and UKMO maintaining the High around the UK until the weekend at least.

UkMO at t120hrs.

http://www.meteociel...20-21.GIF?25-17

so this continues the much drier period for a few more days which i guess is welcomed by many-temperatures still rather depressed for now.

The main interest from there is the pressure on the block from the northern jet and it seems the GFS is still keen to push it away into the continent turning the flow into the south east for the UK.

http://nwstatic.co.u...45121804360ffd;

some warmer air moving into southern areas by this time.

We will have to see how this compares with the 12Z ECM as its 00Z run was keen to drive that Atlantic trough further east into the Med thus maintaining a colder pattern for the UK.

So next weeks evolution still up for discussion that`s for sure.

[No Balls Like Snow Balls]

Some milder temps being pushed into the UK by the start of next week on the 12z GFS

I should add that the mean 2m ensemble temps over the last couple of runs have been a few degrees lower than the op, so it might be the same again that the op run is overdoing the temps. I think some higher temps would be welcomed by many.

Edited February 25, 2013 by No balls like Snow Balls

[Milhouse]

Some milder temps being pushed into the UK by the start of next week on the 12z GFS

I should add that the mean 2m ensemble temps over the last couple of runs have been a few degrees lower than the op, so it might be the same again that the op run is overdoing the temps. I think some higher temps would be welcomed by many.

A pleasant weekend on the cards but sunshine amounts remain open to question, however by then we should have cut off the source of all the cloud at present spiling in from the east. Temperatures around average but light winds making it feel pleasant. Looks like some frosts by night too so classic early Spring weather.

UKMO in agreement bringing a dry and fine weekend.

[Wilkybarkid]

No one here today - so rather than lurk as I have done for the past 5 years I will post.

Given up with GFS this winter. I ignore all its output post 96hrs.

I used to think it a good model for trend spotting. However it only spots trends as it is run so often it shows every variable possible. Which isn't really trend spotting more a model akin to monkeys, typewritters and the complete work of shakespeare.

Thus I think its output not just tonight but for ever should be ignored - I recall Ian F has commented that it's what the professionals do at the meto with regard the gfs.

[snowking]

Just a quick one

The overnight ensemble mean heights were pointing towards the scenario once again progged by the ECM 0z det - that is troughing into Iberia, with our heights over the UK being replaced by lower heights to the south, likely keeping the UK on the cold side of the jet stream and offering something akin to January (in terms of synoptic setup - it's really rather feeble attempting to place any specific details on things at this stage)

The key thing here is that the initial Scandi trough to our east reloads cold into the continent, and so should something like the ECM 0z/Ensemble mean suites verify, then we are looking cold into the 10-15 day period.

The GFS det looks an outlier against the ensemble means, though any solution should not be discounted at this stage.

Generally though over the past couple of months, the combination of ECM and Ens Mean heights have offered the most accurate signal into the day 10 period

SK

[bluearmy]

the 12z gfs op develops that arctic ridge n of alaska in fi and given the option of a frigid eastern seaboard or a frigid nw europe, guess which way the algorithms head ?

[Summer Sun]

Both GFS an UKMO are in agreement to t144 tonight by keeping high pressure over the UK by the end of the week we may see things brighten up for a lot more of us as the high begins to move it should cut off a lot of the cloud which is currently coming of the north sea

Surface temperatures should be pushing close to 10c by sunday

The cloud should also be a lot thinner for many in England and Wales this weekend allowing the sun to break through

Edited February 25, 2013 by Gavin.

[Yarmy]

Both GFS an UKMO are in agreement to t144 tonight by keeping high pressure over the UK by the end of the week we may see things brighten up for a lot more of us as the high begins to move it should cut off a lot of the cloud which is currently coming of the north sea

Surface temperatures should be pushing close to 10c by sunday

The cloud should also be a lot thinner for many in England and Wales this weekend allowing the sun to break through

Certainly hope so, I've forgotten what the Sun looks like.

[Skeggy Winter Storm]

Both GFS an UKMO are in agreement to t144 tonight by keeping high pressure over the UK by the end of the week we may see things brighten up for a lot more of us as the high begins to move it should cut off a lot of the cloud which is currently coming of the north sea

Surface temperatures should be pushing close to 10c by sunday

The cloud should also be a lot thinner for many in England and Wales this weekend allowing the sun to break through

Really hope so gav likewise forgot what the sun looks like put my winter hat away for 9 months looking forward to spring so its looking at models for slow progress to springlike weather

[Altohumorous]

Further to my correlation with the same period of the year (end Feb/start March) in the fairly recent past, most of the early and mid-90s had cold spells from north or east in this period, a couple short-lived (but right at the turn of the months), others lasting a week or more overall. Definite trend of easterlies during this period too.

[chris55]

the 12z gfs op develops that arctic ridge n of alaska in fi and given the option of a frigid eastern seaboard or a frigid nw europe, guess which way the algorithms head ?

Not quite sure on that one Nick...what do you think? lol. Northern US V cold!

If that depth of cold was heading to the UK then my winter towel would be very much retracted!!!

[Panayiotis]

ECM seems to be struggling with the energy over Greenland, compare the 12z with the 00z at 144hrs:

Edited February 25, 2013 by Panayiotis

[Methuselah]

At least one thing's certain: irrespective of what the models suggest, things can only get better...

[karyo]

ECM seems to be struggling with the energy over Greenland, compare the 12z with the 00z at 144hrs:

It looks much closer to what the 12z GFS and UKMO show so unlikely to be anywhere near as wintry in FI as the 0z was.

[Panayiotis]

It looks much closer to what the 12z GFS and UKMO show so unlikely to be anywhere near as wintry in FI as the 0z was.

Its actually not that bad..

[chris55]

A March snowfall is still a possibility, although the models were hinting at this a few days ago for the 3rd now we are looking further ahead.

[karyo]

Its actually not that bad..

Up to 168 hours it has taken a step towards the GFS.

It improves by 192 hours but it is on a knife edge!

[Panayiotis]

Up to 168 hours it has taken a step towards the GFS.

It improves by 192 hours but it is on a knife edge!

Yes very! I would guess at snow from this for the north:

But cold and potentially snow is being pushed back and kept in the realms of Fi, hopefully there is a glimmer of hope tonight within the ensembles!

Edited February 25, 2013 by Panayiotis

[karyo]

Yes very! I would guess at snow from this for the north:

But cold and potentially snow is being pushed back and kept in the realms of Fi, hopefully there is a glimmer of hope tonight within the ensembles!

The 216 and 240 hour charts are promising and the best from the major models for cold. However, as you say, it continues to be pushed back and It almost feels cruel to me!

[SMU]

A very pronounced reverse circulation around 60N depicted by the 00z & 12z ECM operationals- Certainly drawing attention away from the lackluster & poor performing GFS.

With such a significant negative index developing for the AO in the mid term- the prospect for more wintry developments could present themselves for the North & East in particular.

The -20c isotherm lurking over Scandi is always something good to see, but as ever the journey to the UK is never a straight forward one ....

S

[Cheese Rice]

ECM has so much potential, all dependent on that pesky high, a push north east would do wonders.

[nick sussex]

The ECM tease continues with broadly the same pattern as the 00hrs however heights are lower over Greenland and we don't see the complete removal of the PV to Siberia.

It's very difficult to sustain cold in the UK with a western based negative NAO however the ECM operational does develop some cold uppers more especially for northern areas.

The problem at this range is shortwave activity near Iceland which the models don't pick up well this far out, I think realistically to have a chance at a more wintry picture you'd need to see the pattern further east and south.

You've also got the problem of phasing and for those that saw the GFS come out you have that taking place to the west of the UK, essentially when that happens low pressure to the sw gets pulled ne too far west and then its game over.

I think for the timebeing the ECM is still a low probability with the GFS trend more likely given past history,we'll see over the next few runs whether those odds change.