Uncertainty

A mean 1040mb Scandi high at day 8 with a bitterly cold Southeasterly wafting back into SE England? This is a huge development from this time yesterday, backed up by op runs and fitting with tropics / stratospheric developments. As always a couple of days to count it down and the surface impact on the U.K. completely obscured at present. But the likely hood of blocking persisting is increasing fast.

Incredible cold over mainland Europe, any retrogression of that monster high and that’s getting advected right into the U.K. I bet there’s plenty of ens which will, even if this run doesn’t... We await the wording of the MO long range outlook with interest...

I mean, why shouldn’t this happen? The MJO is firmly in phase 7 at good amplitude. And forecast to perhaps stay there for quite some time. The multiple strat weakenings still have plenty of time to filter through the levels of the atmosphere. The forecasting strengthening up top may well be relevant for late Feb or March, but it won’t be the driver of the medium term tropospheric situation. The clusters from last night are quite illustrative of the evolutions on the table: So either: The Atlantic breaks through, a benign, springlike U.K. high or the GEM. The GEFS has been keen on options 2 and 3 for quite a few runs, the ONE thing they are v useful for is picking a FI trend and it, the blend of the above EPS clusters are clearly there... A pretty significant mean SCeuro high there, but given the clusters trifurcate as EPS above, it’s only representative of a blend of v cold and quite mild runs. If winter had been mild thus far, many would be getting very excited about the situation day 7-12, but as it is, most will rightly be far more concerned with the intense imminent cold spell we have inbound in the short term: Minus 12 850s forecast by the ECM at the range it truly excels at. A very rare spell of weather coming up, call it what you want, it makes no difference. It’ll be cold with very frequent showers . One highly pertinent point for western areas in this particular Easterly is the question over the westward extent of the lake effect snow showers. Some models, and indeed the MO warnings suggest not very far is the answer, but the UKV and Swiss model seem to push showers, born from the temperature contrast between air and sea, right across mainland U.K. @SingularityJames I read your excellent article about this spell and you mentioned you thought the snow showers would penetrate much further than most models would suggest, do you think this chart is realistic? What the GEM is showing would have no semantic debate attached and would make February the month of the beast. An incredible period of model watching, payback for cold lovers for the heartache of the last two winters (and the 5 before that).

Maybe that CFS barnpot run was on to something? EC46 heads back to the freezer into the start of March! After a brief, and perhaps debatable, milder spell back end of week 2, the regimes support a continued domination of blocking patterns for the foreseeable The chances of a genuine, colder than average winter (given 5%, understandably, in the Dec contingency planner) are increasing fast.

This is low number 5. The previous 4 have all gone under the block. Even mambo number 5 is having a go! Go on my son! Wat

I don’t think it’s a contradiction as such, these situations are so rare, almost mythical that they require near 100% model agreement to have a chance of verifying. The very fact the GFS, one of the worlds top models (although an irksome and highly flawed one) was dissenting from the majority view meant that it had to be taken seriously. That’s why it (and the ECM over the weekend) were driving everyone in the weather world demented with their stubbornness! Equally, the fact it has now come into line with other output gives the Countrywide easterly more credence. You are right that there is often too much emotion driving this forum but that is human nature - it manifests everywhere from Twitter to tower blocks. It’s up to the readers to make their own minds. You make a good point though and you should always feel free to ask questions and receive respectful, informed answers. Hopefully the weather will reward us with an epic spell this time.

Time to get the rulers out. Flat as a pancake. Both phrases apt for this run, and indeed most winters. Except, of course, the heights are the opposite way round! @DiagonalRedLinedo you remember that chart you made JFF back in early December, y’know, the opposite of this one? Crazy to think we’re 5, yes 5 days away from actually realising this! Then mean is certainly more conducive for snow in the SE, not as extreme for Northern areas as the 12z but would certainly make for more of a nationwide event. Huge support from ALL major models now for this event. Expect it to filter into the ‘real world’ consciousness very soon. Sat - Weds look the key days for the snowy easterly, then signs on EC, GFS and GEM of a potentially very snowy breakdown from the SW come Thursday. Reminiscent of storm Emma and the 2018 event. Signs also of a strong Atlantic back end of week 2, and taken at face value that may be the case for a time. However, the EC46 suggests blocking, and with it winter, might not be done with us yet even after our upcoming dance with the Eastern beast...

One for the South here... The Arpege has had absolutely no interest in this cold spell and has kept the low plonked over the U.K. throughout, think ECM a few days back... Now it piles snow showers into SE England All this On Sunday! The GFS and GEFS got storm Christopher’s ejection point way wrong 2 days out. They have had countless other calamities whilst, obviously, the EPS haven’t as much. At this short range and with the hi res models now coming into line you have to go with a GEM/UKMO/ECM blend here. Expect more GEFS members to be more like the present GEM which, btw, is seriously cold for almost the whole of the UK

Yes ECM! In cricketing terms, this one’s a Guzzunder! If you don’t like it, have 12 hours later from the 0z instead The cricket analogy for that one would be a total collapse, usually by England. All in all we’re still clueless really with this horrid trough. so many of us want that long fetch unstable easterly, and that could still happen, but this time last year we were facing the true abyss (last years ECM 192 for reference, the reality was worse) whereas this time literally anything could happen, so much to talk about. It’s a very interesting, exciting period of model watching. This day 9 ECM is a great example...has more snow potential than most years: if it slides more cold to come... if it clashes then its big snow for many... Ps Whatever you do... don’t look at the Arpege!

The GEFS have improved significantly at day 8-9 after a relatively lacklustre 12z 18z 12z The 18z shows a very cold Easterly with the Atlantic trough hitting the buffers... The 12z shows a mean N North Sea high cold but not very snowy. This continues at day 10 with a mean easterly on the 12z and a strong one at that compared to a SWerly flow on the 12z. Upgrade anyone? Crucially, the EPS has also improved from a cold perspective from its overnight run 12z Para looks very good too GEM —> after a day or two of U.K. highs has spat out two stonkers in a row UKMO —> Colder earlier and looks ok with the Arctic high link up A U.K. high and an incursion from NW remain possible solutions, but the v cold easterly is very much in the running tonight. But the NOAA chart doesn’t give much credence to the former. What a chart that is btw. Last night after the ECM mean I made it clear we were on the rocks with this cold spell but the 0z pulled things back and the 12z have continued the good progress. With one note worthy exception: will the real ECM please stand up?

I think this run, the very latter stages of the GEM and, to an extent, the post day 10 potential on the ECM show that getting this first bite of the cherry isn’t the be all and end all. I think a full on BFTE scandi high at day 9/10 now looks unlikely based on tonight’s outputs but, as I will keep reiterating, the background forcing, extended range modelling and professional meteorologists opinions remain strongly biased to cold / very cold outcomes over the coming 5 - 25 days. So it doesn’t seem like a 2019 redux to me yet...

Yes @Allseasons-siEarly days, but this GFS18z has the cold moving back south quicker than it’s 12z... looks a more secure evolution to cold than ECM /GEM A good suite would at least take the battle into the morning when hopefully the models can regroup. Icon looked like it would go on to form at least a bog standard Scandi high. I reckon we’re gonna know by tomorrow night whether the initial ‘bite’ e.g after the midweek trough clears, leads to deep cold or not. Right now the models clearly don’t know, hence the huge array of outcomes. Indeed, the change in jet profile on the 18z sees the Northern arm coming out of the states bifurcate more, leading to the Atlantic flow taking a near vertical angle, leading to a robust omega style block to the N of the U.K. It might not be massively snowy initially, but given the garbage the ECM just spat out, I’d take this evolution in a heartbeat...

It’s bizarre how you can build up to a cold spell in the U.K. for days and have it snatched in one set of horrid runs. I mean, We had a ‘That GFS’ type run, 6 god damn hours ago!!! So... Will this go down in the tyranny of failures (list too long and sad to mention) or will the 0z runs come to our rescue? It has to be said, that the vast majority of the time in this situation, it’s the former For now, EC has joined the 2nd cluster from this mornings output. Which has now swelled considerably. There were already small signs - iffy UKMO, a swerly at day 8 on the GEM, a less defined ridge to the North on the 12z GEFS and the subsequent loss of our solid 1035mb Scandi high from yesterday’s golden day. Not the 2 solid days of upgrades I said were required yesterday. The difference in the ECM mean at day 10 from this time yesterday is stark Yesterday Today The 850s make me Looking through the extended eps late on, around 20 have a giant block to the NE / N / NW but 10 have a horrific SWerly with a Euro high. The others are relatively non-descript, mostly anti-cyclonic. If we miss out on this opportunity it categorically is not ‘it ‘for this winter to say that would be total folly considering a) The 2nd strat weakening hasn’t even finished yet b) The mjo won’t be getting to phase 7 for 6 days at least c)it’s one set of runs and d) February hasn’t even started yet! However, and I say this with a heavy heart... Based on my experience using a similar methodology to @feb1991blizzard, if tonight’s trends are not reversed on the 0zs: It (This particular shot at deep cold day 8-11) is finished Why doesn’t this happen for mild weather

Yes Nick other than the EC op if the means stay rock solid for 6-8 more runs then we’re just about there. GFS p showing the worst case scenario, could see UKMO heading that way with minimal Atlantic ridging so this isn’t quite done yet. Ec op And JMA op not also not ideal so until we get everyone aboard a waiting game it remains (albeit a really exciting one!)

I think that last comment is highly pertinent Si, in Feb 2018 once the existence of the Scandi high was agreed upon the means upgraded with time closer to the event. I remember there were a great many ‘dodgy’ ops (A bone dry ECM and a few horrific GfS runs?) but the means were rock solid. I put a wish list up a week or so back and, despite a delay we now have many of those early collectors items before a genuine cold spell. Over the weekend I will be looking for the following: - A fully onboard UKMO with an obvious progression to cold - An ECM op from the ‘other’ side of the envelope to tonight’s guff - 4 GEFS suites in a row with a mean 1030mb Scandi / Icelandic area high - X model agreement on the ‘rough’ idea of the evolution to said high. With no dissenters. (We knew from Jan 19 from one bad ICON / ECM op that the game was up) Though hopefully we’re less reliant on the wanderings of a sketchy Arctic high than that disasterous affair. I mean rough idea as in for example it’s obvious what’s going to happen (not for snow location ) synoptically up to the Monday trough on the models but after that uncertainty ramps up big time. There are still lots of things that could go wrong but that ECM mean tonight is beautiful. So enjoy it before taking your station behind the sofa for the morning runs!!!

The 46 is sensational Week 2 Week 3 Temps Euro Troughing still present into late Feb Getting BFTE vibes...

That’s it tho Feb we’ve been here before this winter, but not with the reversal/mjo push concurrently. The EC mean turnaround tonight is also noteworthy, SW to E mean. Lots of the runs get there w/o a big Atlantic height rise, the wedge just sort of materialises which is even better really. makes you think there’s big forcing on the pattern not a reliance on a sequence of iffy steps. Two solid days of upgrades needed here and we can start popping the corks.And perhaps get some clarity on what category of easterly rather than whether it’s going to be one. Having the Meto/BBC on board calms the nerves, and that GEFS mean is outrageous @CreweCold, but it’s no in the bag yet. It needs to be there in the morning first!

Notwithstanding the fascinating permutations up to day 7, the thing to look for in the coming days to set up the longer term ‘proper cold’ is the amplification set up by the low off the Eastern Seaboard at day 10 The ECM has it, as do many of the GEFS perturbations that go on to produce big time blocking 2-3 days later. I’m not certain the EC would, though you would think so... but the trend is also apparent on the GFS suite including both ops and fits with the MJO lag. Worth noting that this scenario has been signposted frequently this winter and the ‘bridge’ between the Atlantic amplification and Scandi heights has never quite made it into the reliable, or even to 120 for that matter. I suppose we haven’t had the MJO momentum kick to back it up mind... Alternatively, there are also hints tonight that the day 6 low could disrupt as Nick has described it. Given the last few days have seen the cold trend southward and disruption and SErly movement increase with time there’s every reason to think that might be the case for that low too. JMA a good example of this, with barely a wedge to send it under We’ve all seen how snowy that scenario could be ala GEM so plenty to sink our eyes into over the coming days, with a particularly big 46 coming up too give us some clarity as to where this is all headed...

Looks like a mean easterly later on the GEFS, would correlate with the signal on the 12z op and para. We had this signal a few days back so let’s see if it sticks on the next few runs...

Deep cold v v close on the para Anyone else seeing a purple cat looking towards the U.K. there? Could be a sign... Also, something notable, the usually mild ramping BBC monthly outlook goes all out for Greenland heights later in Feb, out of the range for the up to day 10 models for the moment, but not something I’ve read from them before really and they usually play cold chances down (probably because in recent winters we haven’t really had any!) The extended EPS are, thankfully, very blocked again towards the end and, as the signal for a phase 6/7 push seems to have maintained we are still in the game for Feb. It must be stressed though that unless we get really lucky with that Scandi wedge( nearly in the para and definelty on the GEM) which is unlikely then we’re waiting really towards day 12 or 13 again for the next phase. Saying that the trend towards disruption this week is not the norm so if that were to happen for the day 8 system then we could be in for a nationwide battleground U.K. snow event. I’d give that one 20%. Oh, talking about Greenland highs... There it is, right on cue!

Yes BA they were horrific. Didn’t want to moan in here as many people were looking forward to their first snow of the winter and I didn’t want to spoil their day, which at least 30 of the EPS members would have, unless you worship long fetched southwesterlies!

Look at the jet! That is not a Bartlett chart! It’s heading almost due north from Azores towards the pole with a 1050mb N.Scandi high advecting Siberian cold around the rear towards Europe! With a trigger low about to disrupt near the U.K. Where’s the southern heights??? On the other hand the para illustrates your point perfectly!

Though the para is showing how this can go wrong, the WAA is half hearted Still no clearer this eve

you sure?

Good evening It is quite bizarre that with this anomaly: It is still questionable whether we will end up with a ‘colder than average’ classification for this winter! I mean come on! Perhaps not quite enough red over Greenland / Iceland but still, one would expect a pretty cold CET with that 500mb analysis... The final classification for this winter (both in the statistical sense and the judgement of many of the readers of this forum) depends upon the evolution of the pattern into the early part of Feb, which I feel and have felt for quite some time, holds the best chance for a nationwide, highly notable cold spell this winter. But I am still yet to see a convincing evolution amongst the models. A few concerns on this afternoons runs that I hope are rectified ASAP: - The para has backed off from its wedgey snowy output and pushes the cold well back (gets there eventually but the cold uppers are washed out of Europe by repeated AH incursions and we’re back to square one) - The 12z GEFS are iffier for big time blocking and cold, with many members getting there but like the para, disappointingly late in the run. - The EPS, whilst not short of blocking, still offer little guidance on the expected pattern beyond day 10 and overall, the weather still seems to be coming from the west on most members, though there will be some snowy undercuts in there too. - Other ensembles, such as the NAEFS and GEPs are fence sitting also So the wait for clarity in the extended range goes on. A promising development in an earlier timeframe is noted on the EPS for next Saturday: Last night’s 192 Tonight’s 168 More evidence of a wedge and the low now moves across S U.K. and would bring a risk of snow on the northern side. Remember this is a mean chart so it’s noteworthy. The 144 UKMO is also toying with a wedge after clearing the low but it looks a little out of place compared to the other models, as it often has at that range this winter, so I’ll note it down in my log as pending 0z inspection. Finally the 8-14 NOAA chart now has the low anomaly slightly east of the UK, more snowy chances you would guess, but not a powerhouse Easterly or Northerly. This has been an frustratingly fascinating winter that has promised so much and sort of delivered. Many parts of the S will get their snow fix tomorrow and there are plenty of chances for winter weather in the short, medium and long term. It just doesn’t feel like it’s truly ‘kicked off’ and, if February fails to deliver the goods big time, it will surely be remembered as a ‘teaser’ winter rather than a classic.