Spring Model Discussion 18Z 9/3/13 onwards....

[Summer Sun]

Snow fall becomes very marginal at t240

[mushymanrob]

yeah could be marginal snow events for some later this week going of current chart outputs, but im not expecting any settlement except on higher ground. what we had today typified what we get in march... snow showers, sometimes breifly heavy, that all but disappear on contact with the ground.

the outlook isnt one that will suit most, wet, cool, mostly cloudy.

edit... forgot to look at gfs in fi ... suggests something milder, but its done that before. one day itll be right!

Edited March 11, 2013 by mushymanrob

[chris55]

This Low needs watching, ECM takes the centre down to the West of Wales, and then it fills in situ. Uppers not to spectacular, but I have seen snow in March from uppers of -3/4. A true "slider" looks unlikely at present, but it could throw up a surprise over the next few days. One to keep an eye on.

[Frosty.]

Tonight's Ecm 12z is very much in line with today's meto update with lots more cold weather ahead (by march standards) with further risk of snow for northern and eastern areas and for higher ground in particular. The complex trough covering the uk later this week will bring less cold weather with rain but the far north of the uk may remain in the cold air with further risk of snow and then as the trough edges southeastwards, cold air could flood down across the uk again with widespread frosts and ice, the models are showing that the further north in the uk you go, the more wintry it will potentially be. There is a risk of disruptive snow tomorrow night and throughout wednesday into thursday in the far north/north east of the uk with accumulations of 4-6 inches, with even higher totals for the hills/mountains, low pressure spreading fronts in from the west during thursday with rain but turning to snow as it hits the cold air and then back to rain again, but possibly staying as sleet or snow in the far north.

Edited March 11, 2013 by Frosty039

[bradymk]

Snow fall becomes very marginal at t240

you know the charts are cold when Gavin is showing a +240 chart Seriously, hope you get some warmth after today, truly bitter out there! Unfortunately or fortunately for some, the outlook looks cold for a while yet, although not on the same scale as today and tomorrow but still cold, especially for the time of year with some exceptional northern blocking, a synoptic dream at the moment. Some will no doubt see more snow in the next week, higher you are and further N, the more likely. Hopefully all this northern blocking now wanes and dissapeaea for the summer.

[Mucka]

GFS 12z Op was a steaming outlier by day 4 so best ignored.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=234&ext=1&y=39&run=12&runpara=0

http://176.31.229.228/modeles/gens/graphe_ens4.php?temp=1&x=232&y=33&ext=1&run=12&runpara=0

[Tim Bland]

Last 3 frames of ECM are entertaining... How often do you see low pressure moving west over the uk and ending up in the Atlantic ! But of a sleet fest in store for most..would have been epic in jan / early Feb

[bluearmy]

just a note of possible interest probably lost amongst the inevitable concentration on looking at the radar today - naefs shows a building of heights to our east in week 2. a continental soueaster in late march should be ok for some pleasant weather. maybe some brightness too.

[mushymanrob]

GFS 12z Op was a steaming outlier by day 4 so best ignored.

http://modeles.meteo...un=12&runpara=0

http://176.31.229.22...un=12&runpara=0

i would never ignore any model, just maybe put it on a back burner. often what appears to be an outlier can turn out to be the herald of a new trend/pattern. many wanted to bin the gfs in dec 2010 because it was the first to show a thaw. it was proven to be correct.

[Panayiotis]

GFS 12z Op was a steaming outlier by day 4 so best ignored.

http://modeles.meteo...un=12&runpara=0

http://176.31.229.22...un=12&runpara=0

Whats your location, because I dont know where that ensemble is for.

[Summer Sun]

The London ensemble has roughly a 50/50 split from the 22nd

[nick sussex]

A lot of variation in the ECM postage stamps at 168hrs in terms of trough placement:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

Troughing very close or over the UK, could prove interesting especially to northern areas, quite a few solutions there look to have the troughing more favourably placed with a cold undercut from the east or ne.

I think that's the main uncertainty going forward, will it be wet and cool/cold/ or wintry.

[Gibby]

Good evening. here is the latest report on the 12z output issued from GFS, UKMO and ECM for tonight Monday March 11th 2013.

All models show Low pressure over Northern France with a biting and bitterly cold NE flow over the whole of the UK. Through the coming days the Low to the South is shown to move away East as High pressure slips South to the West of the UK. Winds back through North towards the West by the middle of the week as well as decrease considerably. Snow showers will plague Eastern areas throughout this spell with some more prolonged snowfall possible in the SE today. Through the middle of the week showers will turn from snow more to sleet and rain in Southern and Western areas from Wednesday before Low pressure develops to the NW at the end of the week brings more general rainfall and less cold conditions at least to the South and West but still the risk of further snowfall over some Northern and Eastern areas, especially over the hills.

GFS then shows deep Low pressure over or just to the North and West of the UK with strong winds and heavy rain for all in temperatures no better than average in the South while rather below in the North with snow on hills here. Through FI tonight Low pressure anchors further West of the UK pulling winds from a milder SW or South direction with rainfall more plentiful in Northern and Western regions while the South and East become relatively milder and drier. high pressure then builds from the SW of Britain with any rain then restricted to the far NW with dry and bright weather further South with perhaps patchy night frost.

The GFS Ensembles show the operational as a milder option among the group though not without some support. In general though the slow recovery to less cold but not mild conditions remain with rain at times with Low pressure close by.

The Jet Stream shows no real sign of moving North for any length of time. There is a new Northern arm which moves SE over the UK as we move into next week but it remains weaker than the main flow which continues East over Southern Europe.

UKMO for the weekend looks wet and windy for most with Low pressure setting up shop in the English Channel by Sunday with outbreaks of rain or heavy showers circulating around it. Temperatures will be higher than of late but it will still be somewhat on the cold side with snow falling rather than rain on the hills of Northern Britain at times.

ECM shows Low pressure over Southern England on Saturday then relaxing South on Sunday with a cold and cyclonic flow of winds over the UK in cold air. Some heavy rain or showers look likely for all with some further snowfall in places, mostly but not exclusively over the hills. Later in the run Low pressure remains in total domination of the UK weather, to the East for a time then retrograding unusually West with a rather cold Southerly flow delivering some potent thundery and possibly still wintry showers to end the run.

In Summary there is very little sign of Spring tonight unless you believe in the far reaches of the GFS operational run. There looks to be a lot of cold or rather cold conditions to come over the next few weeks with Low pressure close by making for some potent showers of rain with the risk of hail, thunder, sleet and snow all very possible in any one place over the coming period with some frost at night. There should not be a repeat of the current severity of cold though after tomorrow.

[Dean E]

This Low needs watching, ECM takes the centre down to the West of Wales, and then it fills in situ. Uppers not to spectacular, but I have seen snow in March from uppers of -3/4. A true "slider" looks unlikely at present, but it could throw up a surprise over the next few days. One to keep an eye on.

JMA goes for something similar at +144hrs.

But agree, the uppers are not best placed, especially anywhere south of the Midlands...

SM

[Cheshire Freeze]

GFS 18z much more like the ECM with the trough further east

Colder air infiltrating further south

Edited March 11, 2013 by CreweCold

[Captain Shortwave]

The mid range is very complex with a trough going between 2 others and possibly interacting with either one of them, both or none at all. GFS shows it all, over the last 24 hours it's churned out pretty much every possibility haha. This run interacts with the trough to the north which brings in a northerly for Sunday.

[Cheshire Freeze]

Bank bank BANK this run so far. A very disturbed and unstable N'ly shown at the weekend

That disturbance is shrouded in cold air.

[mountain shadow]

Where were these synoptics in January!!??

Whilst well below temperatures are likely over the next ten days, I fear any decent lowland snow will be restricted to night time.

Amazing to see none the less.

[Captain Shortwave]

Bank bank BANK this run so far. A very disturbed and unstable N'ly shown at the weekend

That disturbance is shrouded in cold air.

Superb, cold core low, probably some beefy showers which would throw the full shebang of precipitation with probably some heavy localised snowfalls with possible thunder/lightning. Later on it looks like we could get a beast of a north Easterly brewing with that massive Arctic high and the trough slowly drifting in central Europe

[Cheshire Freeze]

Superb, cold core low, probably some beefy showers which would throw the full shebang of precipitation with probably some heavy localised snowfalls with possible thunder/lightning. Later on it looks like we could get a beast of a north Easterly brewing with that massive Arctic high and the trough slowly drifting in central Europe

It's a bloomin' brilliant run for cold/snow/interesting weather lovers. No doubt about that. Top notch for middle of March.

Still cold out to 216 hrs

Edited March 11, 2013 by CreweCold

[Panayiotis]

Wonder where the 18z lies in the ensembles, quite a cold reliable run..

Edited March 11, 2013 by Panayiotis

[Captain Shortwave]

It's a bloomin' brilliant run for cold/snow/interesting weather lovers. No doubt about that. Top notch for middle of March.

Still cold out to 216 hrs

Haha unfortunately the GFS got chucked out of the bar when it hit low resolution

Edited March 11, 2013 by Captain shortwave

[Panayiotis]

Lovely NAVGEM tonight:

I wonder is those -20C would even reach our shores? Now that would be epic!

[Mucka]

NAVGEM quite consistent, here the trough has sunk a touch further SE than the 12z

Edit

Panayiotis beat me to it

Edited March 11, 2013 by Mucka

[stewfox]

Where were these synoptics in January!!??

Whilst well below temperatures are likely over the next ten days, I fear any decent lowland snow will be restricted to night time.

Amazing to see none the less.

Had 19 days of lying snow this winter but yes would have been interesting mid Jan