Cheshire Freeze

A lot of dross in there too...circa 60% end up with no discernible wintry pattern at all by day 16. No wonder Ian F has said there's a raft of outcomes on the table at present.

Oh I do love a nice unstable northerly Yep there are some decent looking perturbations around but would like to see these at 144 hrs rather than nearer 384!

I saw all of this coming when we missed out on the first attempt at retrogression progged for early this week! It's why I was so annoyed when the GFS backed down to the ECM.

Saying that, not far off a 78/79 grail scenario here. I suspect the N of the UK would be buried under feet of the stuff whilst the south is slightly milder Zonality reversed there!

As Nick has pointed out...I wouldn't get excited at all given the complexity of the evolution to get to that point. Frought with difficulty around the Greenland/Iceland area. Also, the theme of WB -NAO crops up again..

How the hell did we get into a position where heights to our S are an issue?

Surely that one conveniently placed shortwave isn't going to stop the retrogression is it?? This is the UK...it probably will!

Ok so when do we reasonably start to suggest that things perhaps aren't going to the (earlier) plan? In my eyes, the GFS runs of today have 1) Moderated the modelled stratospheric activity towards month's end (as has been noted by others) and 2) They have produced very underwhelming FI periods whereby the tropospheric vortex seemingly gathers some traction I Just hope we see some swing back in the modelling soon to evoke some excitement once again. Mid latitude features aren't many peoples' cup of tea when they're after some snowfall and a bit of a cold period.

I read cluster 2 as more wet than white...would be dependent on depth of LPs and just how much any weak blocking to the N deflects/disrupts them to our advantage. A high risk,potential high reward scenario. Cluster 3 is a banker for cold.

If we can't get cold I guess I'll have to settle for having my roof blown off

Cluster 3 is the one we're after....Otherwise we'd all have to descend upon the eastern tip of Kent to get a sniff of a snow chance!

All a bit of a mess.... From this, you'd think an easterly was likely with the troughing advecting the cold air under the block eventually. However, as we've heard from bluearmy earlier today, this idea is not even on the table as far as the EC goes Haha after all that, the high sinks into SE Europe

Getting that deep troughing down into E Scandi/Russia/NE Europe is a major part of the jigsaw going forward

All systems go at 174 hrs. We have the pebble shaped block, primed for retrogression...energy disrupting against the western periphery of block

That warm pool though...All brought about because of a poorly aligned/positioned Russian HP. Going to have to grit our teeth through this one.

Don't worry, I'd noted the same thing. The issue I have is I cannot recall an occasion in history where a west based -NAO was quickly followed by something more suitable for our shores. In fact nearly every WB event I've seen has ultimately led into a period of cyclonic weather for the UK. That is why I'd like to try and avoid it if possible!

I think I remember GP posting the other day about the strat ridge going straight through Greenland with lower heights either side (Canada and Scandi) as we enter December. Now that is the pattern we want to be seeing come to fruition. Winter 2010-2011 ended with a the arrival of a west based NAO...they tend to be pretty depressing.

There are a LOT of WB -NAO in the GEFS...just flick through them and you'll see. FWIW we don't want to see the trop vortex completely lifting out of the Canadian sector because this opens the door for an overshoot of retrogression. A smaller, daughter vortex over that way, a Greenland ridge and a Scandi trough would be the ideal scenario.

Hi Will, My thoughts were never centred on any such thing..I think you're referring to my post the other day where I pointed out that the updated GLOSEA5 actually supported colder weather later in winter (Jan-Mar) period....

Aye... On a slightly related note..I feel you've given us all enough hints as to where you feel we may be headed post this potential disturbed PV spell and I'm guessing that none of the modelling at UKMO towers is hinting at such a reversal (SSW)??

That is my main fear Ian..and the reason I want to exploit this weak PV as soon as we possibly can. It's all good and well saying patience required...but it doesn't always work that way...

This is the UK, barring exceptions we are always unlucky Also, we have to take one of those bites of the cherry...otherwise we end up with a nearly winter (like we've seen before) and before you know it we're crying into our cornflakes in March! I'm not saying we won't grasp a better opportunity as we move into winter proper...I'm just reminding folk how quick the winter season flies by and completely agree with Nick S where he says if it can go wrong it will as far as UK weather is concerned.

No but it illustrates quite well, I think, the importance of that initial push of WAA into the west Greenland locale that was on the 12z GFS. Yes, the general atmosphere may remain supportive of blocking but we will probably have to faff around a while longer now to get the correct blocking in place to benefit us. That's the point I was trying to make earlier. That WAA push allied to the vortex displacing east was THE opportunity for the foot in the door and to get us off to a flier.

Dogs dinner of a result Illustrates quite well, I think, the importance of that initial push of WAA into the west Greenland locale that was on the 12z GFS. Yes, the general atmosphere may remain supportive of blocking but we will probably have to faff around a while longer now to get the correct blocking in place to benefit us.