Winter Model Discussion 18Z 19/2/13 onwards.

[TEITS]

Just been looking at the max temps today and comparing to the GFS. I wonder if anyone can tell me what the BBC were predicting on their weekly forecast on Sunday for today.

Only managed 2C when the GFS was predicting 4C. This is much lower than I was anticipating.

Back to the current output and whilst the focus has been on the SE the latest +72 fax charts suggest the risk is further N!

[Tim Bland]

Massive change at just 168 hrs!!maybe cfs is right?

ECM by 240 hrs. Has a cool northwesterly, possibly snow on high ground? need heights to get further north / north west which may follow from 240hrs?

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=0&type=0&archive=0

Just looked at CFS, doesn't look great to me? Are you referring to a different CFS product?

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=258&mode=0&carte=0&run=10

Edited February 20, 2013 by Tim Bland

[Mair Snaw]

Just been looking at the max temps today and comparing to the GFS. I wonder if anyone can tell me what the BBC were predicting on their weekly forecast on Sunday for today.

Only managed 2C when the GFS was predicting 4C. This is much lower than I was anticipating.

Back to the current output and whilst the focus has been on the SE the latest +72 fax charts suggest the risk is further N!

http://www.meteociel...ax72s.gif?20-12

Was quoting 5c here. only got to 1c here today....

[Methuselah]

Just been looking at the max temps today and comparing to the GFS. I wonder if anyone can tell me what the BBC were predicting on their weekly forecast on Sunday for today.

Only managed 2C when the GFS was predicting 4C. This is much lower than I was anticipating.

Back to the current output and whilst the focus has been on the SE the latest +72 fax charts suggest the risk is further N!

http://www.meteociel...ax72s.gif?20-12

A definite shift, Dave. Have we all been blindsided by the weather again?

[weather eater]

Certainly a slightly different mid range plus evolution from the ECM a chance of a northerly but it still looks like we are heading to a west based NAO to me, a variation on a theme rather than a real shift of evolution.

Was quoting 5c here. only got to 1c here today....

You did well you must have more height, indeed 70m, 3c here.

Edited February 20, 2013 by weather eater

[chris78]

Just been looking at the max temps today and comparing to the GFS. I wonder if anyone can tell me what the BBC were predicting on their weekly forecast on Sunday for today.

Only managed 2C when the GFS was predicting 4C. This is much lower than I was anticipating.

Back to the current output and whilst the focus has been on the SE the latest +72 fax charts suggest the risk is further N!

http://www.meteociel...ax72s.gif?20-12

countryfile forecast had 2/3 today in the east 6/7 in the west...spot on.

[snowking]

ECMWF deterministic take on things then

Midday Friday:

Midday Saturday:

Pretty much along the lines of the NAE/NMM take on things for Friday

Saturday shows the potential from that trough further north, and as LS mentions into SE Scotland too - good to see a much wider spread of precipitation than initially anticipated.

SK

[nick sussex]

Just looking at the latest T72hrs fax chart, we've got that trough which is circled in blue that the BBC forecasts suggest could bring some snow to the ne and n. The warm front circled in red is perhaps what we've seen suggested on the GFS precip charts, this could edge west towards the UK for Sunday, as we saw from the GFS it does raise the dew points after a band of snow moves through and that could tie in with that feature.

Perhaps when Ian F pops in he'll give an idea of what the UKMO think about Sundays prospects.

[Purga]

ECM 12Z was a surprise with cold conditions throughout and most of the UK in sub 528 at t240.

GFS 12z ens still showing a lot of very cold solutions longer term and with the Op a mild run ddiverging from the control which wants to go cold.

Will be interesting to see how this one plays out - springtime on hold?

Edited February 20, 2013 by Purga

[Purga]

ECMWF deterministic take on things then

Midday Friday:

Midday Saturday:

Pretty much along the lines of the NAE/NMM take on things for Friday

Saturday shows the potential from that trough further north, and as LS mentions into SE Scotland too - good to see a much wider spread of precipitation than initially anticipated.

SK

Aren't they identical charts SK ??

[stratty]

ECMWF deterministic take on things then

Midday Friday:

Midday Saturday:

Pretty much along the lines of the NAE/NMM take on things for Friday

Saturday shows the potential from that trough further north, and as LS mentions into SE Scotland too - good to see a much wider spread of precipitation than initially anticipated.

SK

Are they not the same SK?

[UV-RAY]

ECM t240 and a much more potent easterly could be in the offering, with pressure rising over

Scandinavia as the trough over Iceland cuts southeast. Very promising and only 240 hours

away lol.

Yes, the old promising charts at +240 hrs, now where I've I heard that before.

[Harsh Climate]

The latest BBC weather forecast on BBC one shows the snow confined to NE England, Yorkshire and Lincolnshire where it may turn heavier on Saturday, they show no snow for the south on Saturday as things stand

Just in-case no one saw it here it is

Yep, the models have been quite consistent in showing some precipitation over the north east later this week, so can see why they are now forecasting a little snow.

As for the south, nothing notable has been showing up too much on the charts apart from that more dynamic feature that brushes by at the end of the week (unfortunatly with milder uppers.)

I still think a few light accumulations in the north east and high ground in the south east looks the form horse at the moment, with just the risk of something heavier coming into kent for a time on sunday before it turns to rain.

I'm liking the ECM tonight, certainly strong signals for some northern lattitude blocking with the chance of much colder air invading from the north/north east

.

Edited February 20, 2013 by Harsh Climate

[Gibby]

Good evening. Here is the report of the 12z output from GFS, UKMO and ECM for today Wednesday February 20th 2013.

There is little change in the outputs tonight from that of this morning in the shorter term. All models show an inceasingly cold and strong Easterly flow developing over Southern Britain around a strong Scandinavian High pressure. Once setup these are notoriously slow to break down especially in late Winter as Europe is at it's coldest at this time of year and the Atlantic at it's quietest too around now. Through the coming days the High to the NE extends West towards the North of Scotland but little overall change in the synoptics is likely until well into next week at the earliest. Therefore there will be many days of cold weather with a bitter NE wind. Mostly dry weather will ensue but there will be a few exceptions as snow showers gradually feed into some Eastern and Southern areas through the weekend but amounts will be small for the vast majority. Next week sees a slackening of the flow with less wintry showers and dry weather for most continuing with some continuing frosts by night.

GFS then moves on through the remainder of next week with High pressure only slowly weakening later in the week with much lighter winds, less cold days but still some overnight frosts under any clear skies as the High recedes away. Through FI the situation is quite complex but cold weather remains never far away with a South positioned jet flow and bitter winds poised to the far North of the UK for a time though they fail to make it into the UK on this run. A less cold and slack East or Southeast flow over the UK eventually threatens frontal rain into the SW late on.

The GFS Ensembles show rather less of a marked rise in uppers as we approach next week on this run with the rise reduced to average levels before a strong spread between members become shown towards the end of the run. The operational run was yet again on the warmer side of the team as was the Control run a cold one in the South at the end with a steady increase in the chances of precipitation as we move on from the middle of the run.

The Jet Stream shows a split flow still with the Southerly flow the stronger arm carrying some unsettled conditions across Southern Europe at times. The weaker arm to the North rides over our Scandinavian High with very little change likely for some time. A linkage from the Southern arm does mix with the Northern one and strengthen it briefly but proves temporary as the split flow realigns after the middle of next week.

UKMO for next week shows High pressure over Scotland with a lessening of the cold East flow over Southern Britain. All areas will remain cold but it would be dry and bright in places with sharp overnight frosts continuing.

ECM finally shows next week staying rather cold too as High pressure gradually pulls West out into the Atlantic by the end of the working week and coupled with a strong rise of pressure over Northern Canada opens the door for a potential Northerly flow beyond the term of the run.

In Summary tonight there are continued signs from all models of an extended spell of fine and settled weather. After the very cold weather of the next four or five days things will warm up marginally next week but with High pressure largely maintained over or to the North of the UK things will never be very warm. Overnight frosts will be widespread. In the longer term the Atlantic shows little sign of having sufficient strength to break down the block as things stand and the jury is therefore out how synoptics evolve beyond the next 7-10 days but a quick change to Spring warmth looks unlikely to me anytime soon.

[UV-RAY]

Looks too me that after the next 5-7 days temps will at best only return to normal values. Could be a cold CET by the end of March maybe.

[Carlrg]

A definite shift, Dave. Have we all been blindsided by the weather again?

Crickey where did that come from. As far as i know (but please correct if i'm wrong) nobody picked up on this. Who'd be a forecaster? Deffo not me.

[SMU]

Crickey where did that come from. As far as i know (but please correct if i'm wrong) nobody picked up on this. Who'd be a forecaster? Deffo not me.

Its been there for 2 days- Problem was it was masked on here but people moaning about it being dry.

Amazing despite all the comments from people on here that have seen these situations time over - saying that it will unlikely be dry for very long most assumed it would.

Im not suggesting any huge great depths, but with from T36 - T132 we have nearly 5 days of snow potential - so we should hear of lots of areas having snow falling, perhaps not many though above 2/3 cm.

still fun though & after all thats what we are here for.

Steve

PS for all those comments around ECM overdoing the cold we are now progged on the NAE for -13c upppers into Kent Friday

http://www.weatheron...M=0&PERIOD==

The first time since the glancing blow from the NE in 2005- so 7 years ago!

Edited February 20, 2013 by Steve Murr

[shaky]

ECMWF deterministic take on things then

Midday Friday:

Midday Saturday:

Pretty much along the lines of the NAE/NMM take on things for Friday

Saturday shows the potential from that trough further north, and as LS mentions into SE Scotland too - good to see a much wider spread of precipitation than initially anticipated.

SK

That shows a washer streamer set up aswell!!i think the streamer would travel a lot further inland than the ecmwf is showing but we see whay happens!!the midday friday chart and saturday charts are carbon copy!!

[Yarmy]

It's been a great winter at T240, it has to be said.

[That ECM]

I'd call that a semi-tease! Certainly the UKMO and ECM at 144hrs are better for retrogression,with the now to be named retrogression gap! Its between those two lows to the sw and nw, you need that gap to appear to allow the high room to edge west.

The output for much of this winter is like a girl I knew. Promised much, delivered for many but I missed out more often than not. Still, better not moan to much, she not a bad wife!!

[Methuselah]

Its been there for 2 days- Problem was it was masked on here but people moaning about it being dry.

Amazing despite all the comments from people on here that have seen these situations time over - saying that it will unlikely be dry for very long most assumed it would.

Im not suggesting any huge great depths, but with from T36 - T132 we have nearly 5 days of snow potential - so we should hear of lots of areas having snow falling, perhaps not many though above 2/3 cm.

still fun though & after all thats what we are here for.

Steve

PS for all those comments around ECM overdoing the cold we are now progged on the NAE for -13c upppers into Kent Friday

http://www.weatheron...M=0&PERIOD==

The first time since the glancing blow from the NE in 2005- so 7 years ago!

True, in part, Steve. But didn't all of the snowcasts themselves also concentrate the most intense falls in EA and SE England?

[Mair Snaw]

Certainly a slightly different mid range plus evolution from the ECM a chance of a northerly but it still looks like we are heading to a west based NAO to me, a variation on a theme rather than a real shift of evolution.

You did well you must have more height, indeed 70m, 3c here.

Yeah maybe that the bbc forecast only covers Matlock 8miles from my village and 120m lower so guess that helps a little too.

[chris55]

Just looking at the latest T72hrs fax chart, we've got that trough which is circled in blue that the BBC forecasts suggest could bring some snow to the ne and n. The warm front circled in red is perhaps what we've seen suggested on the GFS precip charts, this could edge west towards the UK for Sunday, as we saw from the GFS it does raise the dew points after a band of snow moves through and that could tie in with that feature.

Perhaps when Ian F pops in he'll give an idea of what the UKMO think about Sundays prospects.

Hi Nick this was Ian's post from earlier. Quite unusual to have a front coming in from east to west producing leading edge snowfall, but in this rare situation the embedded cold over the UK is colder than whats following behind from the east!!

Story consistent with previous updates. By Friday, Dartmoor continues to be an area singled out for a little more focused snow given ripe conditions for Channel shower banding. Flurries elsewhere in E. Saturday offers somewhat deeper convective depth but really relies on convergence to offer more meaningful snow showers, as per UK4 prognosis I posted last night. Some localised impacts possible so being watched. By Sunday we're back to skinnier depths and lighter showers; Monday more awkward given frontal/pseudo-frontal feature from E rotating W around top of continental vortex. Likely to offer a trickier forecast hybrid of wintry PPN into E Anglia and SE with potential for a leading area of snow to low levels across Midlands. However, amounts not looking too bothersome at this juncture but it's a dynamic PPN feature so perhaps a more widespread snow potential versus weekend story. Beyond that, MOGREPS-15 retains anticyclonic influence well into trend period, versus the shift to more cyclonic EC members. Latter somewhat favoured, ie to less cold SW regime eventually, but a fine balance of choice frankly and hence UKMO not yet nailing colours to either mast given low confidence.

GFS highlighting the situation in broader sense.

Edited February 20, 2013 by chris55

[Andy Bown]

Perhaps when Ian F pops in he'll give an idea of what the UKMO think about Sundays prospects.

I'm not absolutely sure Ian will be around in the next 4 or 5 days as he posted last week about having leave time off from being on BBC

Points West from today until next Monday.

[Frosty.]

Well the Ecm 12z has built on the 00z run and cracks begin to appear in our anticyclonic spell in around 8 days and continue to advance from there into a more unsettled and cold pattern, this time the north has a chance of snow with cold uppers mixed with low pressure to the northwest, the gfs 12z has a similar idea by T+240 but the ecm looks a lot better synoptically to bring down an arctic spell through early march, the gfs op run is not onboard with that idea and continues to put barriers in the way of a big cold plunge from the arctic but perhaps now the longevity of this settled spell is becoming reduced from what looked like another 2 weeks and is now rather less than that with a breakdown from the northwest now appearing more likely.

Edited February 20, 2013 by Frosty039