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The atmosphere is now reflecting a Nino state and has been for a while - and that chart is a change over the last 30 days chart. The actual anomaly charts look like this Still very much Nino and not Nina. What the oceans look like come March is of zero interest in any hunt for cold now, and any moderation in Nino over the next 6 weeks will not make a real impact on this winter's season. This tweet is frankly nothing more than a scare story. His twitter feed is extremely uninspiring and rather basic. Nothing to see here - move along...

... all of a sudden, some notable model output beginning to appear... Progression of mjo towards favourable tropical forcing phases not to be overlooked here.

That's a really good question. Ying and Yang. Slower progression of the MJO in recent days has added to the frustration on here....but might also add to the size of the honey pot... ECM good this morning - ties in with the 150hpa strat chart which suggests the Siberian lobe of split vortex may be held back further east allowing at least a temporary surge of scandy heights - greeny still the likely direction of travel? Notice also a resumption in wave 2 activity on the vortex Upgrade charts coming inside the horizon. Honey pot visible. Potential longevity of what is coming possibly pleasing ('twas the only negative about the March Beast). HNY to all on here!

Arctic High forming.... mid atlantic ridge holding hands.... and the jet pushed south. Excellent evolution, Southerly jet should help reduce heights over the continent while the Iceland/Greeny GP cell strengthens under favourable pacific and stratospheric conditions. Meanwhile a very cold sector of air over northern Russia looks likely to feed westwards. Gulp. A mid Jan cold spell of near perfect foundations..... based on one 240hr op run. But this has been the shape of the pattern seen for a while - and because it matches the signals I am more inclined to have some wary confidence in these specifics. Off to order a new scraper, some de-icer and make sure I know where I've stashed both shovel and boots...…...

Everyone having fun yet That's a peach from the ECM at 240.. Just been busy on the GMAO run - what a displacement of the Euro daughter vortice.. incredible.

So the MJO is phase 6 today and next couple of days heading into phase 7, the start of the ‘colder’ phases that will aid poleward amplification into high latitudes this side of the N Hemisphere, particularly NAO region initially. ECMWF finally getting out of COD on the RMM plots and getting into phase 8 in around 5 days, it’s been erroneous in killing the wave in this respect and why we are seeing better output at day 10 now, lag effect of colder phases on upper wave patterns / amplification over N Atlantic and N Europe would give 5-10 days after I guess. Couple this with downwelling from the reversal starting today it’s going to double whammy for low heights / tropospheric PV at high latitudes dominating our weather for a while, rather a strong signal towards high latitude blocking. GEFS also indicating no return to westerlies in the polar strat anytime soon now, so the effects of SSW on AO and NAO could be long lasting.

Do they have a -7 on standby on the AO table ! Wow 1070hPa over the pole... Bosh !

Happy New Year everyone . Hope you all had a good time and are recharged to follow our search for the Holy Grail in 2019 ! Which brings me to the ECM run ! In light of recent years I have decided to move to an emergency code red warning . All NW helpline assistants leave is cancelled . Extra supplies of Prozac have been ordered ! The subject of the emergency is the trigger shortwave due around day 7 . This runs around the ridge and southeast , it develops low pressure to the south providing support for any high to the n ne . Longstanding members who have suffered TST Trigger Shortwave Trauma know why I have placed our thread on this emergency warning !

Apart from the ECM looking cold, As others have already said the GFS P gives snow possibilities into next week onwards. The Models are definitely showing a colder theme this morning and what with the SSW taking shape things are certainly looking up. I expect some interesting model watching coming up over the coming days.. December has been very bland to say the least. Happy New Year to all members.

Ian Fergusson‏Verified account @fergieweather W COUNTRY A major Sudden Stratospheric Warming is underway: winds high aloft are reversing from W'rly to E'rly & the stratospheric polar vortex is splitting. For us, this - plus developments forecast in the tropics (MJO) - will increase risks of colder weather mid-late Jan & Feb

OK worth remembering: Not all SSW's produce cold spells in the UK - they increase the chances of blocking and colder weather. Not all SSW's are the same. This one appears to have been a 'displacement' type event followed by a split. Stratospheric events do indeed take 2 to 3 weeks to completely impact the troposphere - if indeed they do...not all do. The current MJO is now expected to propagate into a strong phase 6/7 which would tend to encourage a negative NAO by late January. We've been in a moderate El Nino - which tends to produce milder first halves to winter in northwest Europe and 'colder' second halves. (This can be masked though by the general ongoing seasonal cooling which makes January/February colder than December anyway). This appears to have trended neutral recently. We're at the bottom of the decadal solar cycle where colder, more blocked winter tend to cluster. One slight fly in the ointment is that the QBO has shifted westerly from easterly (which favours blocking i.e. cold) but hopefully it's being damped out by the other strongly favourable signals. The strongest signal for easterlies from both GLOSEA and ECM has always been Mid January - February. There are now tentative signs in the NWP of the disruptive effects of the SSW. So all to play for.

Thanks Lorenzo - Hmm - slightly taken aback at the severity of that third chart. It's at 240h and 10hpa so quite a long way from "reliable" and tropospheric impact....but if the arctic high at 10hpa is going to drive as far south as that and be as destructive as that GEOS image looks then things are going to get very interesting lower down assuming some degree of downward propagation has to follow. This is the only risk at the moment - propagation speed and extent, but GP stated 70% confidence yesterday and I wouldn't want to go against that It's not quite the same as Feb/March in shape given that the daughter vortex is more coherent and closer to home this time around - but the potential for cyclonic action off the continent will be no less potent if we get that downwell….and longevity becomes the next factor to consider. Given signals for renewed warming mid month could we possibly see a vortex in trouble for the longer term? Fascinating. I cant believe we may be entering a period of vertical and horizontal signal/forecast interpretation again only 10 months after the last case delivered so well. That's not the same as me saying "BOOM" quite yet for snow...but the chances are certainly there.

A quick paintjob to explain the trigger shortwave. In the day 6 , that's circled red , the main upstream low in black. The reason you must have low shortwave separation is the ridge extension from the limpet high needs an escape route. If those phase energy gets pulled over the top and you'd need a huge amount of upstream amplification to overcome that after that point. This ridge amplifies in response to the more amplified low. You can see the change between day 6 and 7. The shape of the low moves from the round football shape to more oval and the overall troughing elongates. As this happens the ridge is forced north ahead of that. At the moment the models are having problems forecasting the movement of shortwave energy in the Atlantic. This makes any forecast more difficult because the phasing or not with the upstream trough and shortwave energy impacts hugely downstream.

well ec op is pretty well the same if not prettier the AO headed towards neg 3 and NAO neg 2 by day 10 gefs are solidly negative once dropping around 5th running that ec op on the NH profile shows a clear reversal wave coming from the Pacific side day 5 and ejecting around scandi day 10 ....... given it begins within 5 days of the SSW, i’d call that a QTR ... Berlin charts should be fun to look at in the morning. Note the strat chart imprint clearly on the trop by day 10 .......I hope mr Fawkes isn’t looking! If ec op is onto the correct pattern then this is going to be a good trip to be on!

BOOM SHAKA LAK!

Either way now, it looks like hopefully my fears about the split not being wide enough or long lasting enough could be over, last good few GFS ops have stonking cross polar ridging in the strat with slow signs of downwelling, and its getting near to the reliable as well.

This is a bit OT but after the stonking charts last night I want to just remind everyone what happened last year in the lead up to the BFTE. Last year because it’s most recent but those who aren’t new will know this is pretty standard while the models get a grip on a SSW. SSW happened. Models took a while to show any response. For a while it looked bleak. Then models started to show a BEAUTIFUL response... Then literally one run/one day to the next the response would TOTALLY DISAPPEAR/DOWNGRADE. and then appear again. and disappear and appear again. I want to make a dirty innuendo but I’ll just allude to one instead. My point is. Expect the next week to be a bloody rollercoaster and for hope to feel snatched away and then given back repeatedly.

All these happy New Years it won’t be happy until we see scenes like this

According to Dr Amy butler 65/65 ensemble members show a split by 3rd January

SSW well under way, along with the lesser known atmospheric goings on including the OMG, OMFG, LOL, and the FWIW all calminating in WTF moments.

^^^ beast from the East ....

Yes the GFS operational ( probably about 24 hours behind ) is catching up but not enough to save the run, however if you look around 216 more & more blocking appearing... Remember GFS notoriously bad for energy seperation so it will probably continue to phase the 2 lows for a while yet- Eyes on the better FV3 & of course ECM UKMO looks good but needed a 168 chart...

For anyone who's still unsure, this is a very informative video: I put it in here cos it affects the hunt for cold.

Well..what have I missed, apart from 17 pages since my last post!..I'm noticing some excitement popping up here and there in the output and this is just the start..potentially a very exciting period of model watching ahead..Happy New Year..SSW !!!

ECM = hints at that low going under atlantic / milder conditions =

Careful you’ll get told off

GEFS zonal wind chart with reversal today at 10 hPa 60 N. I'm struck again by the model maintaining the reverse winds right through the run. ECM also has reverse winds at 10 hPa at t240 still: Reverse showing also at 30 hPa at that point. With such an upheaval in the strat, plus the MJO seemingly favourable, we would very unlucky to miss out on a cold spell at some point over the next 6 weeks or so, in my view.

Some interesting overnight runs .......a Murr sausage is never usually a bad thing in winter ......whilst an odd solution, the trough traversing the ridge and dropping down our eastern side was a reasonable cluster from last suite (part of the op and control actually) and the new control also has a meandering upper low which comes nw/se through the ridge and the uk and draws in a cold nor’easter .... ICON and some gfs runs have been trying to throw an upper ridge to our ene on recent runs but never managed to stick it. Ukmo could head the same way as ec with some imagination applied the extended ens modelling isn’t without interest later week 2 as the lows appear to be more likely to be dropping into the sceuro trough from the north/northeast rather than the north/northwest. for once, the week 2 ens output looks better than the ec46 weeks 3 and 4 for coldies .......

Do you also stand outside Santa’s grottos handing kids notes that say Santa isn’t real??? Seriously though the excitement is justified because while yes these are FI charts... they are in the right frame of time and the right response to be an entirely plausible and “jackpot” response to the SSW. Rather than it being pie in the sky charts to lust over this is a situation where these are the expected charts to give the money shot and almost dead on when it comes to trop responses. These aren’t just yet more 240+ exciting charts

Never! However this is the hunt for cold. What else are we meant to post??

Ptb 10 is bonkers

I agree the ECM has been poor at that timeframe but the thing is we don’t need to worry about day 10. The key timeframe is day 6 to 7 . No phasing of trough and trigger shortwave and the former amplifying means the direction of energy inevitably leads to the ridge building towards Scandi . Of course it’s getting over that initial hurdle ! PS every easterly inevitably starts off as a cold outlier because the evolution is more complex and the ensembles take time to come on board .

its still 2018 here...HNY to my UK brethren

Another boomer at 240... Jan 85 redux

If we look at the conditions this winter. We have a transitional QBO (east) around equator to (QBO) west index. The first time the QBO was positive on 30 hPa was this november if we look at the numbers. But that doesnt tell us the whole story. There is usually a 1-2 month lag between this two phases. So tehnically below the 30 hPa towards troposfere area we still have a negative or east QBO index. We are in neutral to weak el nino ENSO state if we look at the 3.4 area around Pacific. The el nino is central based (modoki). Which is for Europe much better than the east based one, if we look at the average anomalies at 500 hPa, comparing the years back. Comparing winters with traditional (east-based) el nino with hybrid and to the one we have this year (central based modoki). Solar activity is very low, we are about just one year away from a solar minimum. Low solar activity usually means a weaker polar vortex in general, which might be happening this year. But we have to combine other factors as well. It is usually true, that the combination of QBO(east) and low-sunspot activity promotes the chance for a colder than average winter in Europe, which is also true for the QBO(west) and high-sunspot activity. I was analysing this things back a couple of years back on the other forum. So in my opinon the current ENSO conditions are very good for us, we dont have a moderate-strong el nino or la nina events, which are in most of the winters the worst for cold winter in Europe if we look in general. I find neutral to weak el nino ENSO conditions to be the best for this winter. But its just my opinion. And with the SSW event happening right now, I think anything is possible. We have to hope for a MJO index (phase 7,8) and some help with the propagation of weaker zonal winds into the troposfere. The morning ECMWF (00Z) run was very impressive for the most of the Europe, and the GFS 06Z (P) followed him. The GFS (P) is actually a new FV3 weather model. Whats happening with the NAM, is it already predicted to go into the negative state in the lower parts of troposfere?

I assume Matt Hugo must mean that ECM 0z wasn't entirely a synoptic outlier

Actually for the Midlands and north into March; this is a brilliant site http://swanstonweather.co.uk/EppingWeatherPages/Index.html

Here we go again though, this is the most important part, i cannot stress how good and important this chart is, this could be the 1947 redux trigger.

Please change tact then for your own sake. Bigfoot is a myth with no science as such to back it up. The hunt for cold has all the essentials of modern scientific "things" to back it up. So eyes down and lap up the background signals (as shown) and also the rather knowledgeable members posts on here - I'd wage you'll find cold before big foot :-))

The zonal mean wind reversal on the 84 into 85 chart below is being shadowed by 2018 into 2019, I checked these last night and compared all other available years to this years footprint. Thats 1979 to present. 84 into 85 are the closest match to my eyes

Yup...ecm has up'ed the anti...as the other-day when it stocked its very decent nor/hem profile. Now gains the break via evolution!!.. And as again..shouts cold....then likely v-cold... Peaches...AND CREAM..COMING TO THE TABLE.

using the table view of the 12z GEFS the coldest for here is a -12.7 850 temp P4 at 342h http://www.meteociel.fr/modeles/gefs_table.php?ext=1&x=&lat=56.108780&lon=-3.162020&ville=# some other -10s and -11s too as others have said P10 is crazy for blocking P14 hints at a beast a few other charts -20 850s not far away...

Nice Reverse zonality at its finest

@bluearmy

FV3 creating that 'loop' I was reffering to

Happy New Year First BOOM charts from me some others cold not far away on the GFS P / FV3

ECM mean @216 is much improved over the 00z 240 mean with more amplitude, the overall 'noise' will phase out any clarity around an Iceland block- but they are certainly better...

Cheer up coldies http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/

Where have all the clever people gone?? Hurry back from your NYE celebrations...you can't leave me in charge of interpreting the model output!!

Happy new year all!