I admire the enthusiasm you're showing Q and it's an interesting analysis but the GFS ens at least aren't backing you up

This mornings ECM ens weren't too encouraging either as the lowest member was something like -11.2c at 850 level down here although there was a cooling trend shown for the first week in March. 

Overall I'd say the signal for cold to reach us has waned even further over the last couple of days although HP is still expected to have more influence from next Thursday or so onwards down here. If we can get some sunshine with it I imagine it'll feel very pleasant too.

Yes, looks more like a feeling of Spring that Winter in the recent and current charts.  With March only 10 days away my enthusiasm for cold is waning.  My only concern is with large high pressure cells meandering around at this time of year because they can take us from spring to winter with a shift in position.

The GEFS 35 day ensembles have been consistently showing an extended period of below average 850 temperatures in March over the past week. The latest run (from Thursday) enhances that if anything. It is quite unusual for the GEFS that far out to show an extended period either above or below average. Often it is just random scatter. 

It may not end up being especially cold but a period of below average temperatures looks increasingly likely from 5 to 20 March

https://www.wetterzentrale.de/de/show_diagrams.php?geoid=49069&model=gfs&var=2&run=99&lid=ENS&bw=1

At least it will be dry .... in the east.

... which frankly is the main requirement for most of us right now !

GFS models again  showing cold to the  east UK , lurking like built up rainfall on a gazebo roof.

The UK snow shield may suddenly cave in as we approach spring. 2013 never really got going until 

Well into March.The uppers are there.

It looks as if the Atlantic will relent and give a dry spell even to the NW next week http://www.wxmaps.org/pix/prec4 The Siberian cold air mass is still lurking but not doing a lot.

GFS - up to Sat 27th there's a controlling LP on the Atlantic, close enough to give unsettled weather in the NW but for the rest pressure is fairly high though still brisk SW winds. HP then establishes properly over the UK 1035mb English Channel Mon 1st and flirts with the idea of  a ridge to Norway through the following week - enough to raise the hopes of those who would like to see a last hurrah from the east without actually delivering it. Some of the colder GEFS options obviously build on this.

GEFS - mild (very mild in S) to Thu 25th and again around Tue 2nd, after which a spread from more mildness to considerable coldness. Dry to very dry except NI & NW Scotland around Wed 24th.

ECM - SW-lies less strong in week 1 and HP not linking to Norway by end of run Tue 2nd but could happen thereafter

Sorry, I meant here in the West won’t get above 13c in last week of Feb, 

I tend to look at Cardiff ensembles nowadays, as they are nearer to me, since I moved

But I am not convinced London will exceed 13c every day either

My money is on Q being on queue - with a quantum of Siberian cold heading our way by the 10th March. The equinoctial effects on the cold makes it less stable, and more “slippery”  and inclined to advection. Makes cold spells more likely but shorter than mid winter ones. So far it is modelled to just miss us - and I did not know this was due to influences of the PV in Canada and all that knock-on to do with Baffin...I would love to know a bit more how that works. 

There are many games of consequences in weather modelling, just like the southerly pushing north on a stalling Atlantic front - if it reaches Svalbard it means a Scandi high forms, but if it doesn’t quite reach that far north, it means a high over Denmark or even Holland and we get dry  cool weather...(in winter), so the Baffin factor is new to me.

Loved the diagram Q, but please could you put some meat on the bones?

There is something wonderful about spring snow events, when the uppers are really cold, because the snow is more sugar like, fluffy, white and more candle floss like. Strangely the rather wet and westerly 70s (after 1970-71 and before 1979 that is, the cold spells sometimes came later - one being the 25th of March: 2.5cm fell in my low lying Sussex home on 2 consecutive nights, to melt off during the day due to intense, sunny, blue sky days....real glad-to-be-alive days - with a touch of night-time magic - of intense alpine type snow-fests.

Tending to follow the gfsp more not only because this will become the new gfs operational run come March but also because it is showing much more consistent northern hemisphere profile than the gfs op run which is swinging wildly from run to run. Look at the difference for ex the 0z run, t192 and the 06z northern hemisphere profile, completely different.

Q's Siberian High is appearing a lot on the GEM ensembles

Indeed, its still there and there is still time for the pieces to come into place.

But its all been alot less impressive over the last 24 hours and that canadian cold pool has been spoiling things.

Mind you the ECM looks a bit better

Yes it looks decent enough until day 9 then hints of something a bit colder. Thankfully the mean at that point is much more SWly and anticyclonic.

Agree, the theory seems thin now, but I am still convinced Qs hypothesis has legs for March 9th +  but we’ll see soon enough, but was there anything in the notion that SSW 3 was of a type that would not cause a flow reversal?

But there was an 'actual effect' from the last SSW: the winds reversed again.  I thought the issue was simply how that manifested itself in the troposphere once it propagated down, assuming it had any measurable effect?  Do we know that the huge Arctic outbreak across much of the USA wasn't a consequence?

Jetstream forming a series of loops on the Atlantic,  the UK is under a S-ly leg of the current loop, which lasts to Thu 25th; the next loop places the S-ly leg to the NW of the UK until Wed 3rd; then after  a brief burst of a direct W-ly, there is a new broad loop surrounding the UK finishing with a strong jet well to the S, in the Med, Tue 9th

GFS - SW-lies this week until cut off by HP developing over UK Sat 27th. That slowly slips off to Norway to allow deep Atlantic LP to approach UK 975mb NI Fri 5th. As that LP passes across the UK it introduces N-lies, strong at first but still present as a weak feature Tue 9th (There was of course no sign of tis LP at this time yesterday)

GEFS - mild (v. mild towards end of week) to Thu 25th, then a dip but recovering and still on the mild side through to Tue 9th though op and control both favour something colder at the end. Short rainfall spike in SE Fri 5th otherwise dry; more rain generally the further N & esp W you go.

ECM - like GFS to Sat 27th but the HP then stays over the UK at least to Wed 3rd with ridge to S Europe.

I'd say the ingredients are still broadly there, but things are not aligning so well as they were a few days ago. The siberian high is weaker and often in the wrong place, while the cold pool over canada is unfortunately doing quite well at strengthening the jet when it nears the E coast of the American continent.

However even with the inferior positioning of the canadian cold pool and the siberian high there is still a good chance cold will make it to the UK in the form of a northerly or scandi easterly. Of course I hope we get some kind of upgrade (there is still plenty of time) that returns to the original solution.

As for the effects of the SSW, I'm not sure; however its quite possible some of the effects in terms of a tropospheric wind reversal haven't been felt yet. Even that notwithstanding there will be a final warming event that makes easterlies generally more likely this time of year anyway.

I think it's fairly obvious your feelings, however misguided and self-righteous they are. Do you not care at all about the forum and the potential implications with posting such obvious bullying in the public domain? Obviously that doesn't need an answer, you seriously need to get a grip if this riles you so much