supernova

Ed, why less convection on this run with colder uppers (gen question)?

Couldn’t see if EPS had been posted yet. Op a significantly milder option compared to the rest of the suite right at the “make or break” point of the evolution. Comforting, even if the trend isn’t.

Sorry, duplication, delete.

Cold pool further east and not quite the inverted shape to the high shown in this morning's run so therefore slower advection of cooler uppers but despite the slower evolution the end result still going to be pleasing to the eye. Voila 192 hrs. All good if not as rapid as we'd like.

Sadly someone with greater knowledge than my hopeful floundering would need to answer that one for us but I'd certainly like to think so. Would be interested to know the last time the NAO was five standard deviations below.

Seems the GEFS forecast for NAO is on the same page too.

Check. And as you rightly predicted the ICON is falling into line accordingly. Good alignment of the high at 144.

By a considerable margin the best set of ENS I ever remember seeing for the Eastern counties. Am gonna see if I can unearth the ensembles for 2009/10 when I get time later - be interested to compare - but honestly I'm not sure they were ever this good.

Darren, your posts on TWO are always worth a second read (and you're right, both forums buzzing today). Am sure your contribution would be most welcome on here by lots of us who are not so knowledgable but remain keen to learn.

Not sure I've ever seen such a Team Jo ramp! Think tonight will be remembered as the night we were allowed to bask in model perfection, the night when promise proved better than reality. For sure it's unlikely ever to be repeated. What a series of runs we've seen today. Memorable. Great to watch the drama, and the reaction on Netweather unfold. Thanks to everyone who contributes and makes this the best weather forum on the 'net.

GFS brings the cold in slightly earlier on the 12z compared to its earlier run. Looking good in a week’s time.

Interested to see whether the mighty ICON can maintain its consitency this morning...06z rolling now. Hoping its 180hrs chart doesn’t change much (for the next 180hrs!). Would be interested to see this model’s verification stats recently if anyone knows where to find them?

Lots of very grumpy people on the thread this morning after last night’s bag of ECM goodies have been stuffed back in the sweetie cupboard. Meanwhile, we have cross model agreement for an easterly including the UKMO which finally comes kicking and screaming to the “last gasp of winter grand finalé”. PS. ECM Op on the milder side of EPS. Jet Stream gone backpacking. Further stratospheric warming predicted (which is likely to batter sister vortex and potentially open door to Greenie high). Chin up.

Good to know. Every model predicting -NAO.

Cannot remember last time METO produced this sort of update. Encouraging.

Small changes early on result in big differences a few days later. Better than we were this morning but there's still a way to go from GFS/UKMO in particular if next week is to deliver a decent shot at cold as opposed to a dry and rather limp-wristed easterly.

Guys, saw a chart the other day where Dr Butler was predicting a -37.5m/s wind reversal - can anybody point me in the right direction of what actually verified if indeed the SSW has peaked yet?

FI seems to be about 96 hrs. Multi-op diversification stark even at short range. Unsurprising really given the record breaking events taking place in the stratosphere where there continues to be mindboggling dynamics tormenting the models. Every measure still heading towards record-breaking levels with no immediate sign of a reversal back to more normal parameters. The warming pattern forecast by the GFS looks confused to say the least if you watch the sister vortex’s path over coming days. http://wxcharts.eu/?model=gfs&region=polar&chart=10temp&run=00&step=108&plottype=ens&lat=53.231&lon=-0.541&skewtstep=0 Nothing nailed on yet. 18th onwards looking like the break point. Might take a day or two for the fog to clear.

Mean heights over Iceland have stuttered slightly downwards from a few days ago (previously 1020 mean by the 20th, 1030 mean a few days later) which reflects a marginally more disparate outlook but the signal is still strong for a Greenie high, and the Op looks a little isolated in the early part of the run compared to the majority of its ensembles members. Control also behind the main group but gets there in the end. Meanwhile uppers for the East coast are as cold as I've seen them this winter (far as I can remember) including the numerous faux Easterlies that never came to pass. UKMO extended is encouraging. ICON/GEM/NAVGEM are blinding (amongst others). The Pro's are unanimous. The long term anomalies are telling. The most seasoned members on this forum are enthused if a little cautious (sensibly so). The Met have been on-board since the SSW was first nailed on. So we're seeing a tantrum from recent ECM/GFS runs but not from their ensembles overall where the signal for cold remains strong. Curious? Kinda. Worried? Maybe. Who doesn't like support across the board. Panicking? Nah. Not even nearly (yet).

Back up the garden path or straght ahead to Route SSW and all the way through Winter Wonderland for an audience with the Beast from the East? Either plausible at this stage.

Well if not a wow then certainly cause for significant optimism, not least as the mean trends downward and both the op and control are at the mild end of the spectrum - noticeably so for the op with the control spiking milder later in the run. Also suggests FI starts Feb 18th looking at the scatter which fits in well with @fergieweather's earlier Tweet. Additionally, some of the well-informed comment on both the model and strat threads have consistently suggested we should look to see influential downwelling to the trop circa Feb 20 onwards. The days might be getting longer, more strength in the sun, blah blah blah but this SSW remains right on track for a record-breaking event and all previous data tells us it'll take more than ten minutes to see the effect at lower levels. All ensembles/means suggesting we're a week away from knowing whether we need to dust off the sledge or bring out the Pledge for an early spring clean!

And according to this Tweet from @MetmanJames, it’s the most significant reversal at this time of year on record. “If the GEFS ens mean is to be believed (and the spread is small enough to support this), this will be the most easterly the stratospheric winds have been on the 10hPa layer in mid February in the period 1980-2016.”

Fascinating watching the models come to terms with the effects of the SSW....the evolution seems clear for a moment then goes all foggy again! Still favouring a Greenie high but too early to be concerned about where the blocking might become established exactly. More worrying for me is the lack of deep cold in either direction. Steve Murr said last night (I think) about needing -11’s or better to avoid anything marginal and I’m not sure where such cold uppers are coming from. We’ve had -8’s over us often this winter and it’s hardly been a nationwide snowfest (great for some obvs but certainly not all). For example I look at the ECM’s take on the next ten days and think GREAT only to look at the 850 temps and begin to wonder where those beyond marginal cold temperatures will originate from. Jus’ sayin’.

Really interesting post this Quick. I think most of us are hopeful of winter's last gasp being an icy cold one thanks to the SSW but as you rightfully point out, nature is often keen to blow a mild Southwesterly-based raspberry in our faces whenever we least expect it. What I do like about this particular stratospheric event is the extent to which the models are predicting favourable blocking and thereafter an Easterly flow from such a long way out (vis a vis METO update). How the next ten days or so unfold is going to make for fascinating model watching that's for sure - let's hope we can find our salvation from the right direction for once and not be forced to witness a dramatic climbdown day by day as we've suffered so many times in recent winters. Been through the GFS ensembles this morning - some unbelievable eye candy in there, by no means all of it at 384 hrs for a change. This my particular favourite (Pert 4) but there are lots more of equal interest. PS. Probably better if last few sentences of your post had been a bit less adversarial but that doesn't mean the rest of it wasn't fascinating

240 you say.... And I guess an Easterly is soon to follow this ECM chart with heights shooting up to Greenie. Might still be all you’re hoping for Shaky