GFS Op 0z: As before, HP moves across Britain now and takes up residence around the Baltic for the next couple of weeks. Its position until Fri 14th means Britain gets S/SE-lies, not particularly cold (an occasional small cold pool passing by) then a slight shift of HP N -wards brings in colder air from the east while at the same time (Sun 16th)  a closer approach from LP on the Atlantic strengthens the wind. The LP retreats only to return Thu 20th with mild SW-lies. 

ECM : like GFS though the 'colder air from the east' doesn't each Britain and looks like it will divert up the N Sea

GEFS : cool to Tue 11th then mean accompanied by most of the ens members near norm though there are some cold outliers. Occasional spits of rain or snow flurries to Sun 16th when pptn shows up in several runs, heavy in SW, some chance of snow in N

I’m in ‘glass half full’ mode. You can see over the last week we’ve enjoyed/suffered a classic rollercoaster with the NWP. It’s taken over 20yrs of studying the subject to learn not to engage with every run in isolation as it will drive you mad with frustration. The ebb and flow of the output is normal - in winter terms we’ve seen it in many of the lead ins over the years, some resulting in the prize most of us seek (2018) and some not (quite a few) but case in mind even in 2018 some of the output wobbled more than Tory chancellor in the run in.

To the here and now, and with a fairly strong signal for the block to drift NW opening the door to the arctic from the NE mid-month up to Sunday, we saw an easing off into Monday and yesterdays output up to the 12Zs was quite uninspiring. Since then, and consolidating this morning, there’s a trend back to this idea with GEM and partly ECM leading the counter-offensive.

This isn’t a done deal either way, and in our latest theme park adventure, the rollercoaster is a fair way from pulling into the loading bay.

I think this has happened prior to all of the relatively few winter easterly spells we have had in the past 20 years, including before the Beast at the end of February 2018. On some days the models have looked generally pretty good for a cold easterly, then on other days less so.

Those of us that were on this forum at this time back in 2005 (I think that's a few of us, me included) will still recall Andy Woodcock's 'winter is over' post (that has gone down in TWO folklore!) when the models appeared to be renaging on an easterly spell they had suggested beforehand. For a while it looked like it was game over for cold that winter, but the models had other ideas.

ECM 00Z Rather ominous looking airmass post 300z to our east, but will it be the beast? - A long way off but still...

I agree but why is it the number of classic winter set-ups seen af F120+ which then fail to materialise af F0 is greater than the number of unpromising set-ups at F120+ which turn around and deliver classic weather at F0 ?

Therein lies the dilemma. You can argue the case for bias, or ‘climatic means’, etc. but the NWP (current scripts) takes initial data and forward projects based on physics. AFAIK there is no room for analogues or matching, although the new AI models have an element of this. The argument that GFS is ‘biased’ towards Atlantic dominance is a little suspect as I haven’t seen literature arguing in favour of that.

I think it’s just bad luck a lot of the time, and the principle applies throughout the year but we don’t tend to see that as between April and October most of us are in snooze mode (I say ‘most’ of us as I’m very engaged in May/June but not necessarily with UK weather).

Unsurprisingly, it finishes up as the coldest member of the ensemble, with the 850mb temp down to -15C. The ensemble average at that time is close to the long-term mean, but the OP does have some support from other ensemble members. Were I a gambling man, I'd say there was a 10-20% chance of it coming off.

Yes, we've had a few of those over the years 😉 Genuine question as my memory is getting a bit hazy but was 2005 the one when we got a cold spell in February and quite a bit of snow down here?

I agree that the chase is almost always more fun than the actual event. It's partly down to our coastal location so any snow is marginal and wet, so although nice to look at through a window, less fun to go out in. Of the last 15 years the only exceptions are Dec 2010 and Jan 2013 with proper, deep snow and with the former, dry and powdery too. Luckily I do get vicarious pleasure from other people's snow!

Yes this one seems to have popped up at fairly short notice. One to watch for the south.

ECM and GFS 6Z both show some potential for deeper cold in the second half of Feb, too. Still plenty of interest.

UKV and Arpege don't seem interested in snow for the south as yet (well, maybe a bit of wintry stuff on UKV over the hills).

There's been a window of activity/areas of instability around this weekend for a few days now, but not a strong signal in the models. I think ECM had been modelling some precip moving across parts of the south in  some of its runs a few days back for example, which gave a sporadic cover. The models do though seem to have developed this over the last couple of runs and instead of it being an area of instability from troughing a fair way to the south, it's now a distinct little feature. I think the models  today have tended to show that feature assisting with cutting off the push of milder uppers for a couple of days, hence a move back to showing the colder uppers lasting until 10/11th Feb, rather than 8/9th.  UKMO manages to largely avoid the milder uppers on it's run as a result of developing the feature and then further development over the near continent. GEM has toyed with this over the last day or so too. 

UKV/UKMO does seem weirdly pessimistic given the uppers -> -6 to -8c uppers but just rain IMBY. I assume that the air is largely from Spain or thereabouts and as such has higher DPs and surface air than if say the feature had arrived from the south east. I'd still expect some wintriness though, so wouldn't be surprised to see some snow over the Downs and a wintry mix for me for a time. 

Not quite model related but but I thought the MetO deep dive yesterday was really interesting and took a detailed look at what may have caused the models to 'flip' a few days back from the UK being in no mans land with HP to the east and the current setup where we do get a shallow easterly, unexciting though it may be. The suggestion was an active surface and upper LP over Hawaii having a knock on effect on the jet and encouraging further surface and upper LPs to inflate HP over the UK (today) and subsequently Scandinavia. He also had a look at the uncertainty in the models around the mid to long term and the conflicting signals. The UKMO model is apparently keener on the Julian Madden oscillation being favourable and helping to keep the jet amplified allowing the HP to reassert itself and allow a second colder shot of air, the other models are less so and as a result are tending to show the atlantic eventually winning out (a few dissenters in the ens aside).  Will be interesting to see what happens over the next few days on that front - currently you'd have to say the odds are low of a colder solution, with a no mans land or gradual atlantic return more likely but then I said the same based on the output before the models trended colder.  Hopefully the same happens again!

The current phase of the MJO is active across the far north of Australia. It’s not exceptionally active, but it’s high summer here so there is plenty of heat and moisture and record breaking SSTs of the North-west coast. As this wave of instability moves into the Pacific by early next week it will be interesting to see the impacts. I watched that met office deep dive and it will be interesting to see what happens with your high. 

It's not overestimating anything for MBY!

Less cold temps to near average from the east when more colder air are in Greenland so i wish and prefer to get that source and better snow chances from the Gap. Easterly seem waste of time nowadays as no longer guaranteed subzero temps that I am only after. 

Seems to settle out everything that falls. That said it is now late winter and ground will be at its coldest. Picking out the heads of the valleys which is a known snow spot….assuming of course the positioning is correct!