IDO

At last, at D13 we look for retrogression as the Siberian high is cut off: Obviously JFF but this was my expectation, but delayed on this run.

bluearmy Yes, I agree. I was watching that cold pool skirting the Siberian high:

We have a two wave pattern, but Alaskan Ridge and Iberian ridge with a weak Arctic high and Siberian block at D10: We will probably need some jiggery pokery to get anything from a setup like this, snow-wise anyway.

Lukesluckybunch I mentioned earlier that Siberian highs are frustrating as the UK ends up in no-mans zone, between the Atlantic and the High with the Iberian ridge getting pumped up. D8:

The GFS stalling the front means that EC and GFS arrive at the same point with up to a 24 hour variation: T96 EC and T120 GFS. But good agreement that there is no return of the front south; the GFS op 0z was an anomaly. Cross-model agreement finally on that stage. Let us see if we can get any consistency post this period.

Lukesluckybunch Both are similar at T90 on the 06z: The GFS is stalling the front as it edges north so continuous snow for two days as it moves from M62 to N Scotland.

I would agree with the Met and that the main risk is the north especially hills and high ASL: The Midlands is snow to rain on high ground.

Uncertainty That is not my preferred outlook at D10 EC mean: Caught between the Atlantic and the Siberian High. Another 10+ days gone for potential snow. IMHO, a Siberian mean high is not what we want. Usually means continental (SE) air and Europe is not that cold. The UK still under the auspice of high pressure with a rampant Iberian ridge. A UK high would have more likely led to retrogression to Greenland and a much quicker route to cold/snow. But ATM, and I would stress that bearing in mind the model's performances of late, it looks like settled and cool as we move into the last half of Feb (EC). So, hoping EC mean is wrong. FWIW the EC op is an outlier at D9+ on all three metrics; eg: Confirming my earlier thoughts that the ops are struggling and that may even be reflected in the means.

The UKMO completes its three-point turn and is now closer to what GFS/GEM/EC was showing for the weekend: Despite days of runs pushing the cold south, it was the last to correct it to the above. I mention this as an IMBY for the South. Those south of M4 probably miss out totally on the fun. GFS op is interesting with Event 1 as it moves towards yesterday's EC 0z of a stalling front as it hits the cold: Looking at members, this remains fluid as the low position, angle, and longitude all affect this outcome. This explains why ensembles are all over the place. So, confidence is middling as to extent and longevity (for some), but higher ground could take a pounding if there is stalling. EC is not as good as GFS, though. It and the UKMO are the worst for the snow to melt quickly: Day 4 EC: Post-D7, it looks like height rises from Iberia. The means at D9: Maybe a weak mean Scandi surface high develops for a short while after D9, but no solid easterly, and any cold air is too far east, and it has a weak flow as the mean high slips south later in the run (T300+). It is early days on post-D7 as we are still ironing out the finer details of the following week. So expect changes, though the means have been confident of UK height rises for days for that period. But the GEM op shows the model's struggles:

For those lost in the one-liners and to and froing, I summarise that there are two events: Event 1/ The front moving north on Thursday will dump snow in the Midlands to the N England region. 1.1/ UKMO has downgraded this versus its 0z run, hence the "fail". Event 2a/ The EC stalls that front and somewhere may get considerable dumping before pushing the cold south. This stops much of the melt and puts most of the UK in cold uppers by Sat/Sun. Event 2b/ The GFS sweeps the cold uppers away and melts any laying snow. Event 2c/ Somewhere between GFS and EC: 2c.1/ like UKMO closer to EC 0z but not as good 2c.2/ like GEM, closer to GFS but not as bad. There is no point looking further than that, as entropy is high.

frosty ground Looking at that African/Iberian plume, getting anything cold from there seems tough. Look where the real cold is: Just a slither of cool uppers, and Europe is mostly mild.

Lukesluckybunch True enough, but nothing like the EC, and that is what we wanted now that UKMO has also moved away from EC. Also, GEM is only scraps, nothing to be excited about, but as GFS is awful, I suppose it looks better than it is. frosty ground I did say at D6, where the divergence with EC occurs. It has not followed the EC. And post D7 the GEM changes every run the last few days. eg, D9 GEM:

GEM stays closer to the GFS at D5-6:

The Met weekly update suggests high confidence in the EC and UKMO for the cold to sink south over the weekend, pushing down to the far south as the low sinks rather than blowing up over the UK! That is certainly a good sign with the Met onboard for a non-GFS/GEM solution.

ICON close to GFS at D7: edit: versus EC:

frosty ground I agree; the GFS is further west at the same time period, so it is a combination of shape, timing and placement of the core low, as you implied. Being further west the GFS (06z) is even worse. The ICON keeps the north on the cold side so hills may keep snow cover; D6

Sadly, the ICON has moved a step towards the GFS with a bloated LP system rather than an undercutting low(s); 12z -v- 06z Meaning (12z v 06z):

ICON a bit further south versus 06z:

Not only is the GFS op awful for the short term, but its FI is poor, with a touch of Spring at D10 and even the upstream wave toned down, meaning no apparent amplification in the Atlantic sector. D11-12: Let us hope EC is correct.

Battleground Snow All models have agreed on some snow on Thursday as the front moves north, even the GFS! Which shows this: So, it's not a surprise a warning has been issued. They did add "uncertainty", "turning to rain", and the "boundary", all things that we have been mulling over. I hope we get the best-case scenario.

nick sussex Yes! I am not saying it is right, but it is more consistent than the EC, which changes every run. Transient snow to rain in England:

AO- The ICON is not seeing much snow up to D5: By D5 the precipitation has petered out. Usual suspects, Scotland and hills and mountains in the north, the best chances.

The EC mean is close enough to the op in synoptic: A potential "event" later this week to break the monotony, but anything blocked still remains later in Feb assuming nothing interferes with that signal.

Lukesluckybunch The mean has been rock solid for a UK high for a while. The trough has always been mobile, and any snow needed to be Wed-Sunday before the pattern moves to UK high. The GEFS mean, D8-16:

As for the GFS, my usual first look, I dismissed that as unlikely, almost certainly an outlier at 2m temps alone, for London: It is the worst-case scenario and not worth spending too much time analysing. The models have been rock solid on the Wednesday frontal snow for a while. The questions have been, how long will it stick and to what ASL do you need to be to get the heavy settling stuff?