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

Yes ECM 240 det is very good and with the sharper trough to the east of the Greenland high (compared to the 00z GFS) heading south east, I'd say a 264 chart would be heading rather cold for the UK..

Yes, it's very touch and go and the HP to the NW could easily slip a bit too much more NW and we could end up with a west based -ve NAO! As always it's very tricky getting cold to the UK and of course the above chart is a long way off.

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

So near and yet so far away!

[Winter Model Discussion 06Z 17/02/13 onwards.]

Just a quick note re Saturday, with 12z UKMO-GM offering a much sharper, pronounced upper shortwave trough moving NE to SW as the cyclonic influence of the continental vortex edges closer at the weekend. Latest run much more developed with this feature versus previous output and ensembles, hence treated with due caution regarding reliability currently.... but MOGREPS snow probability mapping (wIdespread 60% - 90% signal across much of S & central UK on Sat) coupled to interesting albeit not excessively worrying snow accumulation prognosis from UK4-Extended means we'll be keeping close tabs on this one in further runs next few days. Cheers.

Thanks Ian, sounds promising, ler's hope the snow potential continues to improve.

[Winter Model Discussion 06Z 17/02/13 onwards.]

Could have been a cracker but isnt...however t240 could grow into a cracker....chasing end of winter rainbows here

Not really

[Winter Model Discussion 06Z 17/02/13 onwards.]

Yeah, a more dynamic feature in terms of potential ppn (not a showery one) so it's one to watch, but as I stressed, I'm not sure yet how the UKMO-GM handles this (if indeed at all - might not be so keen). Will see how EC plays it later too. Still miles off for getting too fixated upon.

Hi Ian, I'm right on the south coast between Worthing & Littlehampton which is normally one of the worst places for snow (LOL) but from what i can see from the latest NWP outputs we may be in with a shout to suck in a few decent snow showers off the channel at the weekend. We do often get some surprise and unforecasted showers (usualy sleet or rain) here and it would be nice if we could have a bit of fun this time - I usually resort to getting up to the highest points on the south downs to get a very rare fix of something wintry.

[Winter Model Discussion 06Z 17/02/13 onwards.]

Turning much colder with increasing snow risk

[updated 08:00 18/02/2013]

The working week will begin with dry and bright weather across most of the country. It will be chilly early with a patchy frost this morning, but temperatures will rise quite quickly and by early afternoon it should feel reasonably mild and almost spring like. Make the most of pleasant conditions because a big change in the weather is on the way this week. By Wednesday much colder air will be pushing in from the east, and through Thursday and Friday it looks as though winter will return with a vengeance. There should continue to be plenty of dry weather in western regions, but overnight frosts will become increasingly widespread and sharp. In eastern and southern coastal counties snow showers are expected to develop, possibly becoming heavy at times, and pushing significantly inland with accumulations likely. The cold spell looks set to continue through the weekend with only a slow recovery in temperatures next week.

Thank you Brian Gaze for that.

I'm hoping for some snow activity along the south coast at the end of the week, hopefully pushing in from the Channel a bit more.

Fingers crossed, any snow however light welcomed down here.

[Winter Model Discussion 06Z 17/02/13 onwards.]

http://www.meteociel...H1-240.GIF?17-0

At 240 my initial thought was a sinker- but if we look- greenland has cleared of the JET & the atlantic has great vertical advection.

Also a trigger low neatly lined up east of greenland to recurve over us.

The models have granted me a stay of execution tonight-

Looking good this week, I would say 3 ice days on the bounce for me & very very close elsewhere......

I will be interested in both Ians thoughts on the 12's more particular the shower train potential....

S

ECM 240 looks a bit 'dodgy' for longevity and could easily go down the tube to me Steve but I bow to your greater knowledge on this one.

[Winter Model Discussion 06Z 17/02/13 onwards.]

Mmm.. what's going to happen with that feisty little Azores LP??

Could the energy go under our HP and help form an omega block? He says hopefully but not very confidently!

[Winter Model Discussion 06Z 17/02/13 onwards.]

It really is nerve shredding if you're in the UK following these cold pools coming out of the continent with the snow potential on a knife edge.The one thing that hasn't downgraded is the cold pool to the east which is better than a few days back on the ECM.

The cold pool is still going strong with the low in the northern Med pivoting and throwing some instability nw towards the UK at 144hrs.

Really not bad at all from the ECM so far, a bit further north and there could be some real fireworks.

Cold pool is rapidly dwindling Nick

A reload from the N is needed but sadly looks like a no no.

[Winter Model Discussion 06Z 17/02/13 onwards.]

I quite agree, RD.

When you consider that the caution, coming from the more-knowledgeable members (John Holmes, Ian Ferguson et. al.) as it did, was entirely justified: indeed, the forecast skew-T/lapse rate conditions have never looked favorable with respect to much in the way of heavy convective, widespread snowfalls...

I wish they did though...

Welcome to NW, day1973...

You never welcomed me RP ... only joking !

[Winter Model Discussion 06Z 17/02/13 onwards.]

Looks like the pattern is shifting gradually south as time ticks by which is OK-ish for us down on the south coast but not such fun for folks further north who want cold and snow. Still we are normally the one's to suffer cold rain or sleet when most other places are enjoying the snow i.e. in January just gone! Not much snow looking likely here, however, more like a keen cold easterly especially right on the coast / beach or up on the South Downs - hoping for a bit of a surprise dusting maybe?

The ENS both GFS & ECM look pretty soild on a warm up after next weekend as many have commented on

Looks like the last of the winter cold (as opposed to the summer wine ) and a great pity there has been no GH otherwise it could have been so much better. Guess it will come out of hibernation in May thru' to about October

[Winter Model Discussion 12Z 15/02/13 onwards.]

Hi: UKMO note block *could* wane even post-nxt weekend but they lean towards somewhat greater longevity, before what they term an "increasing signal" for the HP to then migrate SE and usher-in the Wrly component. EC EPS has Bristol, for example, back in double figures by the end of Feb. Anyway, potential joy either way for cold lovers (albeit snow might be limited) and later perhaps the springtime aficionados.

Indeed, so a fairly'tame' affair in prospect as seemed likey over the past few days. Me being on the south coast, the synoptics could easily give us a reasonable chance of some cold weather and some snow & more so than some locations further north - for a change! From the expert opinions I have been reading, I'm not expecting anything very exciting but it is a long way off in weather timescales and what is in the offing sure beats mild tedious gloom.

[Winter Model Discussion 12Z 15/02/13 onwards.]

ECM 240 - Just like 'A question of sport' - what happens next??

Edit: with nothing in the Med (LP) to support the HP it would sink and then finito cold spell.

[Winter Model Discussion 18Z 12/2/13 onwards.]

the UKMO GM t144 is quite a slack flow so the fact that exeter are happy to go with this for the time being means they still remain on the cautious side re late next week. clearly the text from the 6/15 dayer adds the caveats that the other model guidance from those ops we see offers a slightly more unsettled picture with a stronger flow and therefore more CAA.

gary's comment that this may not be so far from the previous cold spell may not be too far from reality. i have thought for a while that this was all heading toward a similar end game re blocking/sliders and undercuts. this time we look to get a decent flow of v cold uppers and low dp's to begin with before the flow is sharpened ahead of any attempted incursion. still looks to be no more than a week or so and any snow bearing cold will struggle to make it into march. a good fall with a few days cover to finish the winter would do me fine.

So we could end up with another relatively tame affair?

[Winter Model Discussion 18Z 12/2/13 onwards.]

Looks like another slip towards downgrade from ECM this morning. More of a cold dry picture and with the loss of retrogression towards GH shown a couple of runs back but hopefully we can get some frosty nights and sunshine by day and maybe a few flurries in the East / SE. A change from endless grey skies and marginal sleety stuff!

[Winter Model Discussion 18Z 12/2/13 onwards.]

Is the 12z ECM a downgrade from the 0z? Seems like the really cold air just gets shut out again and so any easterly won't be particularly potent.

[Winter Model Discussion 18Z 12/2/13 onwards.]

the only worry i have now is ian f post about the return of west southwest flow i sopose the pros have the tec to see this outcome would be a shame if this failed im climbing back on the fence for now until its nailed.

My first post on NW after a lengthy period 'lurking' - very impressed by the wealth of knowledge available and especially like the 'sage-like' musings of John Holmes!

Regarding the above post, I believe Ian F was referring to an earlier stance this morning by UKMO regarding the possible 'return of W / Sw regime and was awaiting the latest which he has now recently advised. It reads to me as though the latest MGREPS output now supports the EC N blocking / cold scenario an so supercedes the earlier position. I stand to be corrected of course.