UKMO 144hrs. Probably cold at the surface..

A somewhat familiar pattern from the GFS...

GFS at 312hrs...

Short GEFS ensembles are the coldest yet. And in the longer term the control is fairly frigid.

However...
GEM totally collapses the block in double quick time. UKMO also looks a bit ropy.

Yup, GEM this morning looks like the 18z GFS from yesterday - and as for MetO, it shows a stalemate - that Atlantic low is going nowhere fast. It would probably be cold at the surface still.

In the shorter term, as you say the GEFS are cold, as are last night's EPS (they only reach 3C as a mean high for London by day 9 - a long way off). GEM ensembles also keep very cold air at the surface over London out to next Saturday, only showing much sign of a warm up on Sunday.

In the meantime, we've a solid week of highs close to freezing. Quite unusual for February these days!

Is that kink in the isobars in the north sea off the coast of eastern Scotland a small disturbance on the GEM at 72hrs?

ECM similar to UKMO at 144hrs with the stand off but goes on to produce this..

Fans of "branches" on Fax charts should be delighted with these:

http://old.wetterzentrale.de/pics/brack0a.gif - 12z Tue

http://old.wetterzentrale.de/pics/brack1.gif - 00z Wed

http://old.wetterzentrale.de/pics/brack1a.gif -- 12z Wed

They are, of course, convergence zones - great if you like snow, as they tend to enhance convection for the duration.

There's also what looks suspiciously like a polar low over Shetland on the 12z Wednesday chart...

GFS shows a contest between LP on the Atlantic and HP over Scandinavia for the whole of the run, with winds from any quarter from S round to E depending on the exact position of the currently dominant pressure pattern. The actual effect on UK weather on any given day therefore uncertain but zonal it isn't. ATM E-lies this week, milder S-lies for the weekend, the following week mainly SE-lies, and a colder E-ly by the final weekend (20th).

GEFS currently v cold, slowly regaining norm by Sat 20th and the mean stays on the norm; but both op and control, both before and after 20th, take a much colder course than the majority of runs. Little in the way of pptn except in the W. Scotland similar but with more uncertainty than in the S

ECM shows the HP over Scandi weaker which results in more of a S-ly aspect to UK weather tough the Atlantic LP does not progress to any extent

Not much to add to the charts comments this morning but I will anyway

GEFS now showing solid line of just under -10 850s, rather an amusing 'upgrade' from what it was showing Friday/Saturday, with duration of the cold lengthened too. 

GEM as mentioned is a bit meh although keeps the cold until Sunday - entirely possible evolution but as with the GFS the op flipped and flopped in the days before the cold spell started and I'm a little sceptical it will be closer to correct than any other model.

Bit far out for much in the way of consensus for next weekend and beyond but the trend for a big HP to be sat over Scandi and just about influencing our weather is quite strong. Whether that develops favourably to prolong or rebuild the cold or retreats enough to allow milder Atlantic air back in is debateable. Given the models were overestimating the Atlantic (well GFS/GEM ops) until very close to the current setup, it wouldn't surprise me to see the colder air winning out this time too, particularly if the effects of the recent little warming serve to weaken the jet.

Snow wise and reasonable chances IMBY for some convective stuff over the next few days. Mostly light stuff today and tomorrow as Darren mentioned on the more specific thread but could pep up and Wednesday is looking a bit more promising for some punchier showers to form.

Slightly off topic, but the streamer potential for the next 36 hours is very high: Currently bucketing it down here - but so far depth is c6-7cm, and we seem to be right on the edge one streamer, so some areas have had 4 hours of continuous very heavy snow. Fax charts showing a lot more creases, convergences and streamers to come...so this could be another 1987 in the making.

The notable observation here is just how much later it takes for the snow to develop than forecast. The rain and sleet, turning to snow forecast for Saturday was really a Sunday morning thing, and really its only now - Monday that the streamers have got going. The good news of course is that the models continue to show potential for 2021 to be remembered for one good thing.

Fans of "branches" on Fax charts should be delighted with these:

http://old.wetterzentrale.de/pics/brack0a.gif - 12z Tue

http://old.wetterzentrale.de/pics/brack1.gif - 00z Wed

http://old.wetterzentrale.de/pics/brack1a.gif -- 12z Wed

They are, of course, convergence zones - great if you like snow, as they tend to enhance convection for the duration.

There's also what looks suspiciously like a polar low over Shetland on the 12z Wednesday chart...

 

That feature on Wednesday I think is the same one as per the GEM at 72hrs.

Looks like the GFS ENS keep the fronts out to the west now later this week, the 850 temps increase but the mean doesn't quite breach the -5 line (Manchester). Looks like remaining cold for the foreseeable future if that's correct.

ECM not quite as solid as GFS but still threatens a new cold blast from the east at 240 hours.

The GEFS set is really quite cold especially when you look at the 2m temperatures.

That is a big shift since this time yesterday on the GEFS. I've been monitoring the date that the mean 850 rises back above -5C for London in all of the runs. For most of the time it has been between Feb 11 to 13 but is now pushed right out to Feb 17. Admittedly there are still several mild options from Feb 13 onwards. Other models giving other outcomes too so extended severe cold is not in the bag yet by any means.