There has been a trend - and I'm mentioning it because of the lack of much else to mention - of the ridge pushing NW on Sunday/Monday to become more prominent. It has little to do with us at this time but it does increase the risk of another very cold snowy shot pushing into SE Europe and the E Med early next week.

Chris Fawkes seems to think a SSW has already happened/happening. 

Chris Fawkes Twitter

The Sudden Stratospheric Warming looks to be underway with vortex splitting in two. Winds weaken significantly at 10HPa

This Sudden Stratospheric Warming event is not far off being defined Major the way the winds are decreasing at 10HPa. ..will they reverse?

Very interesting!

I get so confused when there are conflicting posts especially with regards to SSW which is already confusing enough for my little head  

PS- can't help thinking this has a lot to do with me posting my mild January CET forecast

Certainly confusing as we have conflicting views on whether we have a SSW or not but you would hope/expect Chris Fawkes to know. I'm more optimistic than you on this SSW hoping to see favourably placed blocking in two to three weeks.

Yes, as I mentioned it is in the "minor" category currently (and there it may stay!) I remain to be convinced that it can in isolation be used as a reliable forecasting tool rather than one piece of a complicated jigsaw.

Mentioned yesterday that the the more amplified ridge around 144h was worth watching for possible (very long shot) HP formation.

Both GFS and GFS ops have HP build close to UK around 120h-168h.GEFS has some ENS support with 50% showing HP formation at 120 and 144h.incuding one or two with Scandi HP.

However hardly any survive past 168 as Atlantic powers back over the UK.

WRT to the stratosphere I've noticed the NAEFS statosphere forecasts are available on Meteociel

http://www.meteociel.fr/modeles/naefs_cartes.php?ech=192&code=1&mode=4&map=1&runpara=

After the recent warming it doesn't look great to my eyes -forecast for day 10

Anyway that's the last I'll post about the strat... getting on my nerves now.

Back to troposphere where the weather happens, some ridging to our NE has been noted but this surely has no chance of surviving the massive PV onslaught to our NW. Looking through the GFS and GEM ensembles not one shows anything other than it quickly flattening E with the only cold interest for central/Eastern Europe who could get a decent cold blast from the N via the amplification.

Looks like Greece might be the place to be once more

For us full agreement on zonal into the 3rd week of Jan with strong heights to the S (especially on ECM, less so on the other models especially later on) and a very strong and organised vortex to the N/NW

ECM mean day 10

That last chart is about as bad as it can get for coldies. 

Aren't you being very premature in stating that the forecast SSW (if indeed it occurs) will not have a 'positive' (by that I assume 'cold') impact on the UK given the time it takes for effects to flow into troposphere?  It may help deliver a cold setup, it may not... Too early to say surely.

Andrew

Remember the warming is now occurring, but the effects if any are still in virtual model space. It is possible the model itself for SLP and 500mb heights hasn't caught up yet or is incorrect in maintaining the deep PV to our NW.

Right, now I've got that out of my system I'll get back to cooking my chilli for tonight's party . . .

I don't think there's a single person in here who doesn't understand SSW can be a factor, and at the risk of sounding like a broken record and repeating a point made countless times in the last couple of days alone, people also understand it's one tiny part of a weather jigsaw puzzle containing many, many pieces, and actually even the most intense SSW event doesn't even come close to guaranteeing cold for these shores. 

interesting to note that you can still have a shot of cold even without completely destroying the polar vortex- indeed a weakened Atlantic has often given us some very noteworthy marginal snowfall events at this time of year. Having said that, the 10th January chart above in Fothergills excellent post shows a very flat and zonal look with no weakening at all. This SSW could be a close but no cigar event, and interestingly Greece and the Balkans look like getting a good taste of winter into January.  

The ENS mean is pretty terrible.

For larger image, right click open in new tab.

Neil, will you be introducing the cayenne pepper at the 1hPa level in anticipation of a propagation of warming downward through the system, possibly leading to reversal of westward stirring technique?

Indeed Neil.

It has always been my understanding that whenever SSW occurs, it can often take the best part of a month before it begins to affect the troposhere and thus have any effect on weather patterns and forecast models. I for one am not really expecting to see any significant changes in the models until we are some way into January, that is if there are any changes at all.

Yes, this has come out of nowhere. Wont be enough to save us but at least its something to keep an eye on

As a passing thought,I wonder if in the days ahead we'll be adding to 'that' list that gets posted on here about Easterlies and 'Where did they come from'