Man With Beard

GFS 06Z prep charts have 60mm rain falling near the channel isles from Sunday evening till Tuesday lunchtime. Ok, it may not all be snow and that figure may change drastically but it does underline: at under T72, the charts have serious snow potential. Someone somewhere not far from us is going to get hammered.

Well just about everything happening winter wise on the 06Z. Snow chances almost randomly scattered about the country. Frontal snow, front-edge snow, back-edge snow, convection, marginal and non-marginal. Deep cold uppers coming and going. Strong biting easterly winds. Potential ice-days. And it just keeps on coming. And starting within T30 not T300. Is it really the spring equinox next week?

GFS 00Z maintains trend of snow into Southern parts on Monday. UKMO looks similar, perhaps the colder of the two now. Overall, at T114, looking like a much better longterm set-up for continued cold too with low heights moving from Scandi towards the whole of UK again

A couple of stray GEFS runs had the warmer uppers even further north on the 12z - uppers still look ok to me but just goes to show anything really could happen yet.

Am I the only one looking south rather than east? There was a whole lot of snow over Northern France for Sunday night on the 06Z and 12Z - every GFS run seems to bring it further north and now it hits the south coast on Monday morning. edit: ok I see the new posts!

The little feature running along the south coast is there again - consistent with the 06Z - could be fun and games in Devon and Cornwall if it verifies

GFS has a little feature running through N France and the English Channel on Monday morning - southern counties not far away. One to watch.

IIRC, the UKMO also made a mess of the Dec 2012 that never was, it held onto the easterly for at least a day after the others dropped it. I think the models have all had horrible moments this winter. Though I don't recall the ECM being wrong inside T120 that often

This charts sees all of England and Wales below -14 at the same time. Even Feb 1991 didn't manage that, you have to go back to 1987. Just how cold would this have been in January?

06Z has a round 2 and round 3 for cold Here's the beginning of round 2

Well, if you favour the highly scientific (!) method of 'halfway house', you'd have to say the ECM is most likely. GFS - extreme cold pushed south quickly; UKMO - cold stays mainly north, not that cold. Leaving ECM as the halfway house (well, slightly less than halfway to GFS)! Cold but not quite as extreme, but the cold stays in the UK for longer.

Is the GFS trying to throw in a "mild" sector in the North Sea ... only the mild sector is under -8C at 850hPa?? Would be interesting for snow if it was.

GEFS mean still very cold at T144 - no real change when compared with 00Z and 06Z

Just above freezing at T144 But feeling quite pleasant by T240

GFS not as severely cold at T120 compared to 06Z, but still packs a punch http://www.meteociel...&ech=120&mode=1 UKMO ... well it's been out on its own at T96 before and been right - so can't discount the pack following it again

www.wetterzentrale.de/pics/MT8_London_ens.png This is a remarkable set of ensembles for any time of winter - mean 850 temps below -7C for at least 5 days and a few runs in there that are severely cold, approaching -15C at times. Potentially record breaking for mid-March I would think, and not a million miles away in timeframe either. And now with support from ECM op this morning too.

This one's for Birmingham: http://www.yr.no/sted/Storbritannia/England/Birmingham/langtidsvarsel.html

Well winter bites back in FI this morning. ECM actually looks a little frightening at T240, a large pool of -16C uppers over Scandi heading our way. GFS 06Z reminds us it is far too early to forecast a cold snap at 10 days out, but the runs serve as reminders that so long as there is severe cold to the north and east, major wintery weather remains possible throughout March. Definitely not time for "winter is over" posts yet.

Thanks John, really helpful. I think your charts demonstrate how there is still a small chance that something wintery could develop for the UK. However, the relative silence on here today reflects a lack of willingness to chase yet another less likely outcome at T192+. Though Scotland still very much in the game for marginal snow. Another possibility, of course, is weaker blocking to the north allowing a push of warmth from the south - I wonder if this is how things will go?

If low heights in Iberia get established they could stay there quite some time - this would probably result in southerly based winds and eventually mild (dare I say warm?) weather reaching the south of the UK - though significant cold weather may also result from such a set-up if there is a link-up with low heights to our east. So in the 7-14 day range I'm expecting an easing of the cold and eventually mild/very mild, but still a small chance of very cold. An all or nothing scenario.

Remarkable model agreement again today in the early-mid range. Considering that prospects for the UK this week are virtually unchanged from model output mid-last week, it represents the best model performance of the winter. Very surprising when you think we are entering an easterly phase, which historically have led to lots of flip-flopping. Trouble is, I think many of us are hoping for a bit more flip-flopping at the moment. I readily admit I have been expecting more movement in the model output, which was why I haven't given up hope in a more general risk of snow through England and Wales - looks more and more as if we will need localised developments now - troughs developing over the North Sea, increased convective possibilities, convergences, streamers. But a substantial drop in heights during the coldest spell probably has to be discounted now.

The changes on GFS / UKMO this afternoon are in part due to a slower approach from the Atlantic low towards Iberia at T72-T96, this delays the phasing with the cold pool, leading to an initial southerly correction of the lower heights over Europe(T96ish), but less of a pull away from the UK of those dark blues later in the run (T120ish). It is this phasing of the Atlantic low from the west and the cold pool in the east which is going to make significant changes T120 onwards, and I think it will be a day or two yet before this is fully resolved. I'm backing a delay in the arrival of the Atlantic low (as per GFS 12Z) leading to a more static cold pool over France/Germany, less ridging from the Azores and an upgrade in mid-term wintery potential here as the cold pool roles itself over in situ just to the south of us.

I see that the METO, the models and many posters are going for virtually dry right up to the end of this cold spell. Not saying they're wrong, but I'll be surprised. Almost every 'dry' easterly I've seen in 10 years of model watching ends up getting disrupted somewhere. Often, it's not over the UK, but this time we're in prime position. Therefore, I'll be surprised if most places south of Birmingham don't see some snow by Monday.

What's interesting me (synoptically and IMBY I confess!) is the scenario of an ESE blowing down the south coast in -8C 850s (a few model runs have shown this). Has this ever happened before? Lived on south coast for 20 years, can't recall it ever happening for more than a few hours - but, theoretically, it would surely lead to significant snowfall throughout the region, especially in places such as South Devon. Is there a precedent for a prolonged such setup?

A hint of the high sinking over Scandi by T144, but also a hint of heights rising towards Greenland - could the whole HP be sucked up to the North West allowing a northerly blast up the line? Which would result in a prolonged cold spell.