Model Discussion And Chat 19th Feb.2012

[summersnow]

GFS 06z appearing to fall in line to a degree with ECM 00z. Interesting! It looks like the chances of something a bit colder on the horizon are increasing with the possibility of snow.

My own interpretation of this for early March is that there may well be significant snow for upland and northern areas - although any snow at lower levels in the north will tend to not last - unless in sheltered locations. 60/40 in favour of such a scenario IMO.

Still a long way to go however, and with Azores HP still close by, it could easily take charge again in future runs - as it has done pretty much all winter. As I've stated before though, this is one of the more likely times of year for regime change, so more likely in early/mid March than before.

[Tim Bland]

06Z OP has some support from the ensembles. A definite trend for something cooler starting this time next week. some -10C uppers showing for the south so snow in low land southern parts is not out of the question

[legritter]

well some good looking charts this morning ,and good DAM line well and truly over us ,but bearing in mind its forcast and not actuall yet i still think hang fire 24 hrs or so .its just a nightmare that mr azores could want to join the party ,tonights FAXES should start to give us more information , i said back in autumn i would compare past synoptic situations to give an idea of future events well as i half expected IT NEVER WORKS THAT WAY . but i found many a cold snowy spell in march delivering .thanks to those who post interesting charts data etc as my computer skills are limited ,and most of my information comes from somebody elses hard work , hope we all get some fun if it all falls into place ,GFS out soon ,fingers crossed CHEERS

[Earth Wind and Snow]

Some intersting charts starting to show their hand now

Just wondering - I know Scotland did well in early March 2006 with sustained snowfall / snowcover via a northerly. Is there many other instances of sustained snowcover for a day / several days in March for more southern parts. I have often seen snow fall here in March but it usually melts by noon or so and I cannot remember an event that had snow cover lasting all day

EWS

[Stu_London]

1947 had lying snow in the south for quite a bit of March

[Gael_Force]

Some intersting charts starting to show their hand now

Just wondering - I know Scotland did well in early March 2006 with sustained snowfall / snowcover via a northerly. Is there many other instances of sustained snowcover for a day / several days in March for more southern parts. I have often seen snow fall here in March but it usually melts by noon or so and I cannot remember an event that had snow cover lasting all day

EWS

Just two years ago, south of France had very heavy snow from a similar set up to what is being shown in the models. The uppers were colder than currently forecast and delivered record breakingly cold daily maximums for the Riviera. That snow lasted for at least two days on the beaches of the Mediterranean, longer elsewhere. Dates were eighth and ninth of March 2010 if anybody wants to look in the archives.

[MP-R]

Some intersting charts starting to show their hand now

Just wondering - I know Scotland did well in early March 2006 with sustained snowfall / snowcover via a northerly. Is there many other instances of sustained snowcover for a day / several days in March for more southern parts. I have often seen snow fall here in March but it usually melts by noon or so and I cannot remember an event that had snow cover lasting all day

EWS

Not on topic so feel free to delete but in answer to your question, snow lay on the ground for 2-3 days in early March 2004 following snow over the previous weekend. I think it all just depends on depth and how much rain is involved.

[Summer Sun]

After a mild spring like week there could be a fair bit of rain for some on sunday

http://www.wetterzen...s/Rtavn1501.png

Though I think the drought hit south east will miss out on the rain as per usual I feel sorry for all the farmers as this is becoming a very serious situation now.

After that we return to what is becoming a common pattern of late high pressure and little or no rain

http://www.wetterzen...s/Rtavn2161.png

http://www.wetterzen...s/Rtavn2401.png

http://www.wetterzen...s/Rtavn2641.png

http://www.wetterzen...s/Rtavn2881.png

http://www.wetterzentrale.de/pics/Rtavn3361.png

All the cold from the morning has been thrown out the window and replaced by the Azores high

Edited February 27, 2012 by Gavin D

[Timmytour]

GFS 12z seems to indicate prospect of an ice day over a large swathe of England for the weekend after next... big time FI and no reall snow prospects to go with it. But for those wanting a last stab of winter it's more promising to be occasionally there in FI then be faced with what was being modelled last week

[karyo]

_{The 12z} gfs _{is a disappointment in comparison to the previous run as it has downgraded the cold chances for next week. The} UKMO _{is even less inspiring with minimal amplification and a dominant Azores high!}

_Karyo

[Frosty.]

The Gfs 12z shows a rather chilly spell next week compared to the very mild weather this week, temps in some eastern areas of scotland tomorrow will reach 17c but next tuesday it could be nearer 5-7c so quite a contrast but nothing signicant but at least some rain for the drought affected areas next week and rain for many other areas too. Actually the temps this week generally don't look as high as the models were showing recently, this is probably due to a lot of cloud in the swly flow but temps of 11-14c at the end of feb is nothing to be sniffed at, it does look cooler by the end of this week.

Edited February 27, 2012 by Frosty039

[Tim Bland]

ECM at 144hrs is a halfway house between GFS 06z and 12z. We need to see that low on sun / min dig as far south as poss to see snow on its northern edge. 06z favoured the south 12z (Gfs) favoured no one and 12 z ECM favours Scotland..all still to play for!

[cooling climate]

Sticking my neck out I would say the ECM t192 and 216 charts should be worth waithing for.

There thats done it.

I never saw that coming I'll get me coat.

Edited February 27, 2012 by cooling climate

[karyo]

_{The 12z} ECM _{is better than the other two with more amplification but it looks quite risky. At 168 hours the door is close to opening from the east thanks to the strong Scandinavian high and our trough starting to move south. However, the Atlantic looks more active than on the 0z.}

_{http://www.meteociel...map=0&archive=0}

_Karyo

Sticking my neck out I would say the ECM t192 and 216 charts should be worth waithing for.

There thats done it.

Unfortunately, like I said, the Atlantic looks too active in this run and in fact in all the 12z output, which wastes another Scandinavian high!

Let's hope that the 12z output has over reacted on a signal and we'll get a more blocked outlook tomorrow...

Karyo

Edited February 27, 2012 by karyo

[Cloud 10]

ECM remains consistent in dropping the trough down towards the UK,and now at 144 hrs.

Cold and unsettled for the last half of the run,and some very different weather to what we have experienced recently

if it came off.

[nick sussex]

The same old failings seen during the winter are appearing yet again with the models. Initial amplified patterns shown in later timeframes become flatter as these head towards the 144hrs timeframe.

Overall the models have downgraded the wintry potential this evening and both the GFS and ECM make hard work of ejecting the low south at 168hrs, the ECM hardly manages this before the next low moves in , the ECM produces a much better looking Scandi high with better cold to be advected west but the Atlantic rolls in and keeps this to the east.

It shows just how difficult it is to get a low dropping south with ridge backing west over the top to verify.

Although the outlook does look somewhat colder it's hard to see a real taste of winter occuring off tonights operational output.

Unless you're on top of a mountain it just looks cold and wet on the ECM, its morning output was far better, if we don't get a westwards correction in the output tomorrow and a weaker looking Atlantic then I think thats game over in terms of chances for some lower ground snow that can last and not disappear by lunch time.

[NO LONGER POSTING]

Looking at the models really anything is possible...And personally, I want it to be warm towards the end of march because it is when I turn 18!!!! XD

[cooling climate]

No need for any knee jerk reactions off of one set of afternoon runs from the models if a cold

wintry east/northeasterly is not to be then so be it but lets see where we are this time tomorrow.

[Cloud 10]

Still a big difference between ECM and GFS wrt mean height's around the UK,with the GFS wanting to keep things

fairly settled,the ECM the exact opposite.

Interesting to see the CPC update soon.

CPC has updated and looks like non of the above!

Climate Prediction Center - 8-14 Day 500mb Outlook

Maybe JH can make some sense out of this.

Edited February 27, 2012 by Cloud 10

[bluearmy]

MAYBE IF I WRITE IT IN CAPITALS, SOME OF YOU WILL FINALLY UNDERSTAND. THOSE COMPARISON CHARTS ARE AUTOMATED REPRESENTATIONS OF FI OPERATIONAL OUTPUT FROM ECM AND GFS. Knowing what you do about the reliability of operational output post T168, would you expect to base a forecast on that output? No, me neither.

Cpc 6/10 (as opposed to 8/14 posted above), looks good though not sure we will receive widespread wintry stuff. The trough needs to correct itself west and south at the weekend to keep a continental flow ahead of it.

[Frosty.]

The latest models show it's all up for grabs this weekend regarding how the low pressure impacts on the uk, the gfs and ecm show it on different tracks which makes all the difference between rain and snow for the locations in the action zone. I do think it will become colder by early next week, maybe as early as the weekend in the north but that won't be difficult as temps tomorrow will be at 13-15c and 17c in aberdeenshire but temps tailing off a bit after tomorrow but still on the mild side, must admit though that it was equally as warm at christmas.

[bluearmy]

Whatever happens to the depression at the weekend as it approaches the uk, the latest T120 FAX shows the 528/546 dam to be pretty close north to south. Uncertain of it's current track but will definitely be very, very wet where it ends up.

[nick sussex]

A very underwhelming GFS 18hrs run, a brief shot of colder air but nothing much to write home about then high pressure moves in again.

Certainly if ever proof was needed that the GFS lower resolution output is a waste of space its the ridiculous amount of changes you get from each output.

Regarding any colder prospects, hard to say what will happen until we see the models agree on the orientation and placement of high pressure to the ne and the amplitude of the upstream pattern.

Unfortunately the models have moved away from a clean set up of low dropping south through the UK and ridge backing west, one suspects that any cold to the east isn't going to make it far enough west and the UK will be left with a more modified flow with troughing nearby much as the ECM suggests.

It's ensemble mean is solidly behind that, again the never ending low heights to the north and the reluctance of the pattern to amplify sufficiently mean that a last taste of wintry weather looks less likely this evening.

Whether the next troughing can sink sufficiently to bring another chance is open to debate, after a few days of improving cold potential it's a backward step this evening, we'll see in the morning whether theres a last minute reprieve.

[Terminal Moraine]

The disparity between the GFS and ECM continues once we get beyond the end of this week. The GFS is keen to maintain a strong mid Atlantic high, which would keep the majority of Britain mainly dry but with a good deal of cloud, whereas the ECM has a much more active, colder and unsettled outlook with the Azores high pushed a long way south.

The GFS does seem more in line with yesterday's long term outlook from the Met' Office, although they indicated that high pressure would be more persistent to the south rather than the west, but I'm desperately hoping the ECM is correct.

[johnholmes]

MAYBE IF I WRITE IT IN CAPITALS, SOME OF YOU WILL FINALLY UNDERSTAND. THOSE COMPARISON CHARTS ARE AUTOMATED REPRESENTATIONS OF FI OPERATIONAL OUTPUT FROM ECM AND GFS. Knowing what you do about the reliability of operational output post T168, would you expect to base a forecast on that output? No, me neither.

Cpc 6/10 (as opposed to 8/14 posted above), looks good though not sure we will receive widespread wintry stuff. The trough needs to correct itself west and south at the weekend to keep a continental flow ahead of it.

no need to shout bm and the way I use the charts I do feel is giving decent results in what upper air pattern to expect in 10-15 days time. When they change from day to day with their own output or with one another then considerable doubt exists-Ive always said that and continue to stand by that-what I said yesterday morning before my pc crashed I say again this morning although I have yet to see the output from late evening NOAA or the output from ECMWF-GFS this morning.

I'll posy my views later today once I get things sorted.