Model Discussion - 10th March Onwards

[Paul]

Please use this thread to discuss the model output...

Model links:

GFS

ECMWF

UK Met Office

Fax

Ensemble graphs

Ensemble maps

Compare the big 4

[damianslaw]

Oh dear no posts in nearly 2 and half hours indicative of the very 'uninteresting' outlook I guess. In these situations expect only subtle changes in the models from run to run - there doesn't appear to be an awful lot of energy in the jet at the moment so any atlantic attack next weekend will probably be a shortlived weak affair no thanks to the every persistant position of the PV - until this weakens or shifts we will always be exposed to the influence of the azores high.

The models are suggesting a temporary atlantic breakdown by next weekend as the current high drifts eastwards enabling the atlantic trough to cross the country but with strong heights building quickly behind we could easily see a revert back to the synoptics of present.

Perhaps later in the month we may begin to see a change upstream with the PV finally shifting or weakening considerably to enable heights to build more northwards towards Greenland and who knows a northerly - a very common set up for late March when northerlies reach their yearly maxim.

Longer term - if we do see heights building more to the north this will help to promote cooler shots of temps into the very warm SST's to our SW at present which should have the effect of weakening the influence of the azores high. One reason why it has been so dominant is because of the warm SST's - these are helping to allow the azores high to ridge NE towards the country.

[IDO]

No surprise that the 12z GFS has sent the messy low of the 0z run packing. Much flatter on the latest run with the cooler uppers passing through the south very fleetingly. Still, compared to the proceeding week, next weekend will be cooler for all, but nothing you could call cold. We then have two HP's joining forces to give us a settled picture from T177.

The HP then slowly pushes east and temps pick up to around average. A bit messy again from GFS at T276 when it has potential cooler and wetter weather spreading in from the west, probably due to the PV weakening. Still 16c showing up at the end of FI for the SE, but cooler to the west, but still close to average.

This potential pattern change in FI threatens a more unsettled period with lows moving in from the east giving the end of March a wetter outlook, adding credence to CFS's forecast for a predominantly wet & cool April and May.

Edited March 10, 2012 by i'm dreaming of...

[Summer Sun]

GFS 12z remains settled upto Friday for most, although cloud will be an issue for some in any breaks temperatures will respond the best chance of lengthy breaks looks like been in the east, though even in the east it will be cloudy at times

By Friday it looks like turning unsettled for a time from the north, however most of England and wales may manage another dry if not cloudy day with pressure staying at 1020mb

Saturday may see a band of showery rain over the uk this looks like it may be mostly light with temperatures cooler than earlier in the week

By sunday pressure may begin to rise again giving most of the uk a dry but cooler and cloudier day than of late, the far north west and south coast may have some light rain at times

By monday pressure continues to build back in giving the uk a mainy cloudy day again with temperatures still above normal for the time of year

http://www.jp2webdes...o.uk/ds/gfs.htm

Anything beyond next monday is uncertain I would say

Edited March 10, 2012 by Gavin D

[snow drift]

Which ever run you view ECM UKMO or GFS for a lot of the country, there is little or no wind or rain out to T120 . Un happy sailors, wind surfers etc and more importantly little rain for the areas that need it.

[Milhouse]

ECM has the very warm uppers lasting until Thursday (even reaching 10c) in the far south. Overnight and into Friday these are swept away as much cooler air spills down from the northwest setting us up for a few days of temperatures around 10c and a scattering of showers likely. However all the while its becoming progressively drier from the west as HP makes significant inroads by the start of the following week.

[Summer Sun]

ECM 12z

Sunday to Thursday

Dry and settled for many, cloud will be stubbon in some areas to lift however the further east you are it should break for lengthy periods allowing it to feel warm in some areas

Friday to Monday

Friday see's changes happening with the mild / warm air getting shifted into europe and been replaced by some cooler conditions with rain speading north to south, this may linger on during saturday

By Sunday high pressure begins to build once more, it will be cooler than of this week, but temperatures in the south may still be above the seasonal average

Monday and Tuesday see's the high pressure taking charge again and some milder air returns, though cloud cover could prevent it been as warm as this week

http://www.jp2webdes...o.uk/ds/ecm.htm

GFS ensembles show temperatures falling from around the 16th, lowest temps look been around the 18th before a slow rise commences again, rain fall remains zero untill the 17th

Edited March 10, 2012 by Gavin D

[Timmytour]

I expect the impact of the solar flares to be represented in the models from tomorrow and to show up as bringing us the possibility of snow for next weekend.

At the same time, there are one or two problems with my Nigerian inheritance, but once the fees have cleared from my account, i expect my windfall to be arriving around the same time as the snow.

[IDO]

According to the GFS 0z ensembles, FI starts around the 17th. Prior to that 90% of the members are in agreement with HP in charge and a mild setup for most of the UK with little rain.

From next weekend the ensembles T850's scatter from -4 to +8, with a 50:50 split between mild and cool. The control run stays mild right through to the end of FI, apart from a dip around 20-22nd. The OP run apears to be reflective of the ensembles showing a cooler few days around T154, with a buried low that clings to the UK for a few days with a track that at the moment favours the south, with the promise of a few wet days (GFS chop and change with this feature, so low confidence).

From T216 to T276 it is zonal, so average in the south for temps and cooler up north. HP back in charge from then, with temps slowly moving above average.

Looking at the PV, it is still in tact by the end of FI so any long term pattern change remains on the back burner according to this run. However the 18z last night was showing a weakening of the PV so it maybe only a matter of time, especially as the jetstream appears to not be as potent through this run (from T144).

The ECM is similar to the GFS, pattern wise, but is less messy, with no low in the mix. The trough encroaches on Friday, after a mild HP dominated week, and has left our shores by Monday, with a HP taking charge from then, with the north maybe more unsettled. This ties in with their EC 32 run, suggesting HP close by for most of March.

So a mild settled week ahead with less confidence from then.

[bluearmy]

upstream ridges continue to look amplified across n america and now the aleutians. the trop vortex (partially as a result of these) is weakening across the polar regions as we should expect in march. no doubt the last stand will be the greenland area. our mean ridge seems to be in no hurry to depart, although brief incursions of pm air are likely from time to time as one cell drains away and another reforms form the west to take its place.

EDIT: just looking through the anomoly charts for uppers around day 8 and note central canadian prairies showing a positive anomoly > +20c as a result of one of those ridges !!!

Edited March 11, 2012 by bluearmy

[Summer Sun]

Not much changed from GFS this morning, low pressure looks likely to much down from the north in about a weeks time for about 4 days before high pressure takes over again from 288h onwards

UKMO

High pressure in charge to friday low pressure edges down from the north on saturday

ECM

Low pressure try's to move right over the uk but it never really makes the south, next saturday it does before been pushed back north by high pressure on sunday where we see pressure of 1020mb return to most of england, this process continues through next week, by the end of ECM everywhere but the far north west of scotland looks like been fairly settled if not cloudy at times

http://www.null/ds/gfs.htm

http://www.null/ds/ecm.htm

http://www.null/ds/ukmo.htm

[Nick F]

Although it's looking rather mild by day much of this week, the air looks like drying out quite a bit, helped by dry air descending from aloft under the anticyclone - which should allow ground frosts to become increasingly common through the week where skies clear.

Some differences GFS v ECM on the phasing of Atlantic trough arriving at the weekend, 00z GFS slower and holds it back across E Atlantic/Biscay- which even allows an unstable and potential thundery flow into southern England from France. ECM on the otherhand drives the trough quicker into mainland Europe with a cooler westerly flow for the UK.

Beyond, less certainty that HP will build quickly back in as yesterday's runs suggested.

[TonyH]

Rather mild you say?

[Nick F]

Rather mild you say?

Even warm, for the first half of March. Could see some large diurnal differences in temps with the increasingly colder nights though. Something that tends be more common later in Spring though, rather than early March!

[Scorcher]

Rather mild you say?

Yes seems like 20C is quite likely somewhere on Wednesday given how GFS underestimates the temperatures.

[johnholmes]

yes its just possible using the 06z GFS that 20C might be reached/exceeded by a touch. Very spring like for most of the Uk for several days and with close agreement from the models. As the upper trough edges in to the west from about Thursday on they diverge a little as to the position of the axis of the trough. A breakdown of sorts filtering east during Thursday into Friday for western areas. Uncertain beyond that as to how much rain may occur and still pretty doubtful for the dry areas. No detail on next weekend for a couple of days I suspect.

Enjoy spring for many for a few days.

[Nick F]

06z continues the theme of the Atlantic trough stalling close to western Britain, eventually forming a cut-off low.

Given the tendency for a high pressure anomaly across western Europe for much of the past winter, perhaps as a result of a downwind effect of the warm SST anomaly invof the Azores, it seems plausible for trough disruption in this general area. With pressure eventually rising again.

[Polar Maritime]

As JH say's, it is looking very likely somewhere will hit 20c in the sun somewhere on Wednesday.

[ukpaul]

The GFS accumulated precipitation by 192h would be funny if it wasn't so predictable and depressing. Just what is it going to take to get precipitation down here? FI out to the end of March doesn't exactly show anything different either.

Rain, damn you, rain!!

[MP-R]

I think the lack of comments is pretty indicative of the boring nature of this weather. The GFS 12Z though does throw a few spanners in the works for a totally settled picture fortunately. A shallow feature shows up next weekend bringing some rain, possibly heavy to many areas, slipping eastwards before dissipating as heights build again by midweek. Then the Atlantic trough takes a dive to the SW of the UK with a warm southeasterly arriving in the outer reaches of FI so possibly more influence from the low than the high if things go well.

Still no sign of much needed persistent rain for southeastern areas though.

[IDO]

Interesting development on the 12z GFS run. The PM excursion never really gets going, as the resolute HP to our SE holds firm. The cut off low then straddles the west of the UK allowing East and SE England to have a mild weekend (17th & 18th). By T186 a developing HP to the SW pushes the low through the UK, clearing the south in a hurry and by early Wednesday 21st has cleared the UK.

From T240, HP back in charge and temps gradually climb, with the HP drawing in milder southerly winds. Back to 16c by Saturday week in the south. By this time the PV is weakening. As per most of this winter, FI modelling the UK to miss any escaping cold uppers, and instead Europe in entombed in a massive HP, with 21c just across the Channel in France and the UK having max's of 17c.

The low in 8-10 days looks the best chance for the south to get some rain, otherwise little around.

At the end of FI plenty of lows to our NW/W and with the jetstream being weakened, the change to a more mobile pattern is certainly a good possibility.

[Summer Sun]

GFS 12z

High pressure dominated to thursday before low pressure edges down from the north, this set's up an unsettled spell for around 4 days

By 240h high pressure is building back again, by 288h high pressure begins to build quite strongly to our east, high pressure satys with us from 240 right through to the end of GFS which gives us a settled end to March, it also bring back the warm air

UKMO also shows the breakdown by friday, however with high pressure never far away from the south east rain fall here looks like been very hit and miss and some areas may miss out completely

http://www.jp2webdes...o.uk/ds/gfs.htm

http://www.jp2webdes....uk/ds/ukmo.htm

Edited March 11, 2012 by Gavin D

[phil nw.]

It looks very pleasant for outdoor activities this week for the large majority.

The high will bring some Spring sunshine and warmth with temps. by day well up in the upper teens especially for England and Wales.

As ever the north west coastal districts of Scotland will be cooler and cloudier at times with some drizzle as the core of the high eases into the continent later in the week and the south westerly breeze picks up.

This heralds the approach of at least a temporary cooler and unsettled little spell as an Atlantic trough develops and moves towards the UK at the weekend.

http://www.wetterzen...cs/Rukm1441.gif

http://www.wetterzen...s/Rtavn1441.png

It may well be that little rain will affect the south east looking at the GFS output and with the promise of another high pressure spell to follow the protracted dry spell looks likely to continue down there.

Edited March 11, 2012 by phil n.warks.

[Zenarcher]

Monday to Wednesday Summary

Western Ireland and Scotland will remain mostly cloudy but dry. The wind will be mainly breezy but later on Wednesday gales are likely for Western and Northern Scotland. For the rest of Ireland and all of England and Wales the fine settled weather will continue seeing clear and sunny weather conditions and the wind will be mainly light but turning breezy on Wednesday.

Thursday and Friday Summary

Slightly less settled weather can be expected as the high pressure now moves away from the UK. For Scotland, Ireland and Northern England it is looking mostly cloudy with a few showers around however some sunny short periods can be expected across Northwestern Scotland at times. Mainly breezy for these parts but gales across Western and Northern Scotland. For Wales and most of England will remain settled and bright however partly cloudy skies are likely to become more common later. The wind here will be mainly breezy.

Looking at next weekend the three main models agree on that it looks like weak low pressure will cover Southern parts meanwhile high pressure starts to build over Northern Scotland.

Edited March 11, 2012 by weathermaster

[AWD]

I'm not so sure that it will be clear throughout England and Wales over the next couple of days, tomorrow especially!

Both Matt Hugo and Ian Fergusson over on twitter have expressed views and charts from the latest UKMO MESO runs, suggestive of a lot of cloud cover over England and Wales tomorrow, with sunshine at a premium!

Tuesday better, with more sunshine in places, but again, there will still be some cloud cover about too!