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Roll on 4 days, and if seems that we are seeing just this. I think that we have seen that the ECM has the tendency in the past to overplay amplification and blocking scenarios........but, and a big but, when we have downwelling strat events the ECM picks these up a little better because of the better strat resolution. Now we may not see a classic evolution as seen in this latest run, but my feelings are that we will see a block to our north somewhere in a similar position. No need to comment on every run, but imo we see the trend increasing as expected, and I suspect that most of us will witness a significant snow event before the end of winter and most likely before the end of the month. And with a locked in omega type block, that snow isn’t going to disappear quickly......

What's interesting at the moment is the consistency of the ECM op forecast for Tues/Weds. To be honest it's slightly surprisingly consistent - and the fact that both timing and angle of the slider/incoming trough have remained in the same 12 hour time bracket for the last 3 days makes me wonder whether finally we have a handle on the rate of downwell and strat imprint onto the trop pattern. The diving, sliding low remains on a trajectory that is mostly west of England and steep enough for an undercut of cold air to turn the moisture to snow for many. Confidence in this scenario is now about as high as it can be at 168 hours, and before too long we can begin to look at what may follow. So - why such confidence? Leaving aside the MetO reports/video (which if interpreted say a lot....) and GP's tongue in cheek comment about the comparative EPS / GEFS suites there are a number of reasons to be approaching the kind of confidence in product that was possible for the Beast. Ensembles first - EPS ensembles have been rock solid now for days, and the depth of the trough anomaly over NW France is the strongest low pressure anomaly in the NH for next week. Note too the strength of the high - and the expectation therefore that this trough is going to drop hard and fast down and through the UK. Snow chances increasing by that fact alone. Berlin strat slices are also revealing - at 50hpa we have a very slow westerly average now, and a main vortex lobe to our east that has shunted way over the Siberia at 240h However a residual strat trough lies across Asia and Europe....and heights to the NW are forecast to build as energy transfer across the north atlantic simply dries up. 150hpa image shows the approximate end result, also at 10 days There is less of a straight easterly component to the forcing at this point than we had back in Feb, so no scandy hieghts yet in all probability....but as the arctic high strengthens in response to the downwelling of negative anomalies from the last couple of weeks it looks likely to me that easerlies by month's end and into Feb...and maybe more scandy heights in time. And tropospheric forcings? Calculated GLAAM tendency currently is stalled - but awaiting an anticipated uptick which will produce more of a shove for high lat blocking in the 10-14 day period probably, just at the same time as the strat impacts are peaking MJO has been advertised by others to be re enteritng 6 - 7 - 8 before too long. All of this is just fuel to the stratospheric fire. So - if we are to see a fail where will it come from? Not from a rampant stratospheric vortex. Not from a flat Nina signal in the pacific. Strong trough activity off Canada as very cold air hits warmer seas? It will certainly create some sparks via a steep temperature gradient - but is there enough westerly momentum at present to send this through the blocking signal and flatten everything out (as GFS, with its less good strat model keeps playing around with)? Cant see it. Downwell timing has done for that option. Might even help by putting a bit of sparkle into what is left of the jet as it splits/dives south and feeds the trough over time. Solar uptick as per Dec 2012 when everything went t*ts up? Spaceweather currently reads "Spotless Days: Current Stretch: 8 days" - so not a spot in over a week. It's about as good as it can be. And to finish - a look again at the forecasted 850hpa anomaly out east. This has strengthened considerably - now forecast to sit at -8 to -10 from normal in parts - so once we get more of an easterly feed come month's end it is potentially going to turn extremely cold. Time to look in detail at that scenario later. For now - Tues/Weds is going to be interesting and the more cold air we can get in situ from Thurs/Mon the better things will be. 850 temps for Mon as the trough prepares to dive/slide look pretty good to me as a starter of the spell. It isn't going to be diving into warm air that's for sure. Marginal event - but someone somewhere will cash in. And with luck we all get some of the action soon after.....

The charts ba has posted shows the geopotential height anomaly towards the lower reaches of the stratosphere. It shows that the SSW has downwelled to the level just above the trop and significantly so. It favours trop HLBs big time! That is a very negative NAM which translates to a very negative AO

Boom shake the room

mary mother of JESUS!!! TXT BOOK !!!!!

Also a cut off Greenland High at 216- Rare as hen Twins with teeth !

From reading the comments on here, things are apparently looking less wintry and it looks like high pressure will be centred closer to us that had been thought.... .....based off the op run of a soon to be discontinued model with lower verification stats than that of the other main models, and against its own ensembles. So much utter rubbish gets posted in this place.

Massive embarrassment for how the GFS has performed over the past 5 days, and like 90% of us thought it is finally climbing into bed with the Euros. Middle of Next Week could be the start of a really nice prolonged part of winter - It really could be a Winter of 2 halves!

While the 18z roll us out, noticed the 12z GFS is finally picking up on the easterly winds pushing down through the stratosphere making their imprint in the troposphere, -5 u-wind below 500mb at the end of the month, this infers high latitude blocking to develop. Couple this with impressive Rossby wave breaking over the N Atlantic in response to upstream deep cold vortex lobe pushed south across N America, as shown towards the tropopause in the 315K chart from 12z EC below, this wave breaking is usually the precursor to omega blocking highs that have staying power, you can even make out the omega shape, the block favoured by EC to be over far N Atlantic/Greenland/Iceland. This block further re-inforced by the easterly wind imprint from the lower stratosphere dripping down. This pattern could be hard to shift it forms, thanks to forces from above and below.

Wonder where Crewe has gone.. ECM is as good as it gets!

So far, a winter of countless 'BOOM' charts and zero 'BOOM' weather...?

First ever post of yours ive not had to read more than once.. brilliant style you have @tight isobar say it as you see it, the way you go about describing the model output is very refreshing keep up the good work buddy

Well an truly in the love zone.. Even our trough has been on the little blue pills...if you get my gist!!!!!

Anyway...get ready 4 the 12z ride!!!

Have a feeling it’s going to be busy and fast moving tonight so: • if you want to know if it’s going to snow in you back yard , head to your regionals - don’t forget the seasoned posters all have regionals and often post in their respective threads too • We won’t be tolerating personal remarks/digs or otherwise. If it’s in good humour put it in banter. If it’s not then don’t post it. • Reverse psychology and trolling doom posts will also be removed unless backed up with decent rationale. Not a ‘feeling in your tummy’ • please please can we avoid out of context tweets being posted in here, we had a nightmare with it last night, there is a tweets thread. •please report any posts you don’t feel belong in here, PLEASE don’t reply or requote them. •Enjoy! Be nice to each other! It could be a memorable spell coming up.

More ‘pinks’ appearing over the past 24 hrs Tim, should keep a few happy. I’m going to order one of these for next winter, no rollercoaster ride for me

GEFS undergoing major correction towards EPS in the day 8 / 9 range in the NE Atlantic, and that substantively opening the door for Greenland height rises days 12+

cant you lot at at least wait twenty minutes to see what ec op does with the weekend ??

Excellent EC for southern Britain(esp the SE)- i would imagine there will be sheer joy as curtains are opened to a winter wonderland @192 one for the shovel.. 216 One for the snow plough..

Just a few lines trying to decipher what the upper air may be suggesting amidst all the 'chatter' from the synoptic models, GFS in particular. Also to try (!) and get the idea of NOAA data perhaps being missing or at fault due to the Trump shut down. The only realistic comments I have been able to find seem pretty clear that, although not being paid, all human work continues as before and this includes tedning to any of the myriad of computers they use. Anyw to meteorology. The 500 mb anomaly charts are not that good for getting a handle on just what the upper air may be in the 6-15 day time scale. Changes in emphasis, even more basic now and then, and no total consistency between the 3 models I use do not give large confidence in what the upper air is going to look like as we move towards February. First NOAA 6-10 http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php There is no marked meridional pattern over the hemisphere. The value of the contour flow is reasonably low, around 546 DM just south of the UK as that contour dips into the European trough. This is something that all 3 models agree on. This does lead to feeling that the European trough is going to be there in 2 weeks, perhaps longer. This does not settle though how far east it may be in that period. The 8-14 is not dissimilar to the 6-10 suggesting there are unlikely to be any major changes in the overall upper air pattern in the next 2 weeks or so. Turning to the ECMWF and GFS versions http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html They are and have been at some variance in the overall positions of both ridging/+ve heights/ and troughing. As you can see above this continues. Summin g up what we seem to have is a suggestion of some kind of mid Atlantic ridging north at times, with the flow east of this running into a European trough, even perhaps a cut off as EC suggests. Personally I am not a fan of this cut off idea. It allows the development of surface features that, sooner or later, source their air from the Med. Not good if you are wanting snow not sleety rain. Most I know seem to favour a Scandinavian ridge, okay but its position is crucial if it too does not end up allowing the isobars to start to originate in the Med area. To me the current situation, IF it stays the same, that is air being sourced from a pretty cold region NW of the UK, even at times, direct from the Pole, is a better basis for building cold upper air and surface cold. Just my pennyworth, feel free to knock holes in it.

Wowsers, GEFS and EPS couldn't be more different in the North Atlantic through day 10. Some crunching of gears coming up for one or both of them soon. Tempting to identify downwelling -U wind anomaly signal as the culprit here.

Why have stewing steak if fillet & ribeye are the same price....

The ECM has better strat resolution so will pick up on this sooner. I would expect to see some great blocking charts on the GFS too from now onwards.....

Mark my words this gts run is going to be better. Look at the difference in mid Atlantic trough separation and amplification compared to last run at t+132

ECM T 240, really starting to lock the cold in now, this run is an absolute belter!

OK so something in the GEFS 06z to cheer the troops up - a BIG shift to blocked! Mostly Northern blocking to boot. E.G.

WAA over West Greenland rather than mid Greenland. We know what that leads to...

Ok, I'm late to the 12z EC COBRA party, but been busy greasing the runners on our sledge, oh damn, didn't realise the charts were 9 days away, oh well, you never know! In all seriousness though, EC and EPS pretty consistent with the signal in the broad sense for an easterly next week, just we need to hope for a clean easterly and there isn't less cold air dragged in around the low to the south from SE Europe.

Well this will shut a few up

OK folks. I think it's time to move on from the "is the GFS impacted by Gov shutdown" debate. The simple fact is we don't know based on media reports and quotes from one employee (a union rep) and I can't find ANYTHING on the NOAA/NCEP website to suggest there's a problem. If anyone can find official info please post it, otherwise let's draw a line for now. Thanks.

Correct - I wish some people would realise the high variability in the current nwp and stop hanging on every frame the end destination is ‘Euro’ trough of some kind and ‘Atlantic’ ridge of some kind ...... let’s see how we arrive there ..... so much nonsense being posted on the met office threads and occasionally in here I thought this was an ‘old man’s game’ ...........

Another day on the roller coaster! My takes from today: Don't read the Met Office 16-30 day outlook thread. I know from my own line of work about unconscious bias, having read that particular thread I think many of us were primed for utter dross on the 12 suite - that most certainly didn't happen. GFS delivered a half decent run on 12z, forget low res - always forget low res, good job it will be a thing of the past when FV3 takes over. However FV3 less good on this particular run. UKMO and ICON solid, GEM a bit rubbish. ECM outstanding run, possibly best of the winter so far, just got to count it down now, backs up 0z. Massive ensemble support for the early part to T192 at least. Support also from JMA to T192. It's going to snow soon. I can feel it.

As is the tradition on this forum when a cold spell is incoming Those uppers look a bit marginal. we could do with it being a few degrees colder or it might rain.. on a serious note if these charts get into the t72 range this place will be in melt down. wouldnt it be nice to just sit back and watch it tick down without any wobbles? could it? will it? i hope it does. but remember the rules DO NOT TELL ANYBODY ABOUT THIS!

Blocky blocky blocky..

The bed wetting is ridiculous! I havent seen a flake of snow all winter and I love the stuff but I am not going to sit there having a tantrum even if I don't see a flake of snow for the rest of winter! I could half understand the reaction of some if it was March 15th and not January 15th but hey ho.... Eyes down for the ECM. It's getting colder and there will be quite a bit of snow around over the next few weeks for many of us in the UK if you believe what the models are showing and what the Met Office are saying....

Now that's the way to serious cold and I suspect where people should be looking with the ens and anomalies. That's if it's going to happen of course

Tasty evolution on tonight's JMA

Lol.. Any1 whom was doubting AT- amping..and the mother canadian lobe..not getting syphoned-and drained.. Can i think now begin to see the notion...gaining rapidly... That baby is getting large !!

ECM fits theoretical expectations by far the most of the 00z det. runs and EPS of the ens runs. GFS & GEFS have had a positive NAM/AO bias for several weeks now. FV3 mostly not but with a few lapses for reasons I can only imagine. So... ECM 00z may be a bit fast to build the blocking highs but aside from that it’s the most believable solution based on everything we know at this time (yes, the usual caveats apply!).

Guys watch that front coming south Tues When GFS picks up on the colder continental feed ahead of the front - the leading edge & indeed core of the front will probably be more snow in the SE

ECM / UKMO now alligned bang on at 144 That low is going to shear South with -6c in situ over UK !

...except that ENS data posted yesterday showed exactly this sharp drop. I was half way through a post yesterday that I chose not to put up - in case it was way off - suggesting that, if the temp gradient is correct, and we have a trend for modelling stronger ridges to both west and east, the trough could drop like a stone over the UK with not much time for ocean moderation of air and some pretty nasty wind speeds. Every model's op run as of now has the trough dropping through the UK and into Europe on Tues/Weds. The upcoming pattern is looking more solid by the run to me...but the exact track of the centre of the low is going to be key when it comes. I think the MetO text language once again tells a story - covers every possible base. I'm not sure we will have certainty on the track and intensity of the trough until the 24/48 hour window given the range of options on the table.....from the slightly flabby trough of the GFS to the superstorm of JMA. Same direction - contrast in detail. ECM is best of all. Still signs of that slider scenario followed by decent trough to the south without the ferocious gales..... More happy model watching

Your post said no models showing heights to our North JS, which is very misleading to anyone not sure on how to read the charts. At least there is some credibility in the ECM, as the Monthly update from last night fits in with that solution.

This must be pretend then...... ECM

I'm not sure I would totally go along with that MWB There are a few factors in play here, not least the upper trough that plunges south east from north Canada that initiates the surge of the subtropical high in mid Atlantic and then eventually phases with the trough now south of the UK. This is of course a long way from a done deal, But as I mentioned in a post earlier, imo this is a way forward for adverting in some seriously cold air

I'm very interested to see what the 12z bring. Will the GFS move further towards the ECMWF or vice versa. Can the ECMWF repeat or get somewhere close to its overnight run. My main concern is I'm not sure we will have any members left to view and dissect the 12z, as they appear to have thrown themselves off the MetO thread cliff! I strongly advise against heading to that thread anytime soon if you are of a nervous disposition! Wowzers

06z GFS showing more amplification upstream over Atlantic early next week compared to 00z, this in turn forces a low to break southeast towards UK as per EC rather than passing east to the N. 00z for 18z Tues 22nd 06z for 18z Tues 22nd Perhaps finally starting to fall in line with EC and EPS guidance in medium range from now on?

No real upgrades in cold this morning - but then BOOM, look at that ECM run. This is proper winter type stuff, no piddly PM or cold zonal. Beautiful

I really really hope the ecm is on the money . I hope the gfs lovin Crewe are wrong , I really do . The ecm is a stonker again .

Morning ICON is the same as the 12z ECM yesterday ( just a shade colder)- which is great UKMO is ok - colder than yesterday - it has the same trough as ICON at 144 over Iceland, just a bit further NE- Aperge very good @96 as well- GFS - not even viewed now.