The lid as they say might be about to pop 😉

We're still shaping up for a potentially severe spell of winter weather through the heart of winter IMO. Looking like a potential split in the SPV could ensue with a resultant tropospheric ridge somewhere on the Scandi-Iceland-Greenland axis.

Exciting times ahead. 

Meanwhile in the near future, GFS goes for a mild Christmas Day in the S and W (12c Cornwall) , cooler towards the NE(4c Aberdeenshire)

So from what i am getting is that a split in the PV is more convincing or more favourable for cold and blocked weather as apposed to a displacement of the PV? just so i understand I am new to learning about PV and SSW from since last winter 's SSW early to mid Feb so just wondering!?

Another absolute horror show.

Agree horror show at the moment. But I dont expect to see significant cold until sometime around the 10th to 20th January. And that only if we get a split strat vortex which is signalled for about the 3rd January.  We should start to see some more interesting cold charts about new year is my punt

 Barely a frost on offer from the 0z GEFS for the English Midlands in the Ensembles,  a  disappointing set of 2m temps for coldies like me.

Anyone fancy BBQ for the New Year Bank Holiday?

The mildish high scenario looking like winning out, and possibly becoming very mild during the twelve days of Christmas, at least initially.

Martin

A few of the panels are interesting but on balance it's looking poor for cold.

https://www.theweatheroutlook.com/twodata/gefs.aspx?run=na&charthour=06&chartname=ps_500hpa&chartregion=na-region&p=1&charttag=PS%20500hPa%20(GPDM)

GEM picking up on the Christmas Day plume that ECM was toying with 2 days ago.  A recurring theme in the mid range output.

I

I wouldn’t call maxes of 5-8C ‘mild’ - I believe these are around or just below normal? 

I accept your predilection to inject balance but sometimes you come across as a bit too keen to show the milder options. I still believe there are issues effecting the longer range results and we’re going to see wild swings in output appearing in the next day or so. 

Christ on a cracker !!

Come on - for a negative AO, collapse in zonal winds going negative a week after the SSW - this is about as bad as it can get really and I thought DEC 2015 was poor!

Met Office has been quite persistent with colder and more blocked weather by the New yEAR and here we are 1st day of 2019 and we are bathed in temperatures of 12 to 15c !

the immediate response to the SSW is to turn things exceptionally mild indeed!! 

Some odd comments this morning.  The models are firming up on high pressure being close to the UK for the Christmas period.  Exactly how that is positioned and aligned is still unclear but over or just to our south seems favoured.  Close to the high it certainly won’t be mild at the surface 

Out to Day 10 the ECM mean puts a strong high pressure cell just to our south west.

The SSW doesn’t occur for another week and it’s effects on the troposphere are unpredictable and subject to a lag of typically 2 weeks which puts us beyond the range even of the low res GFS.

It's starting from tomorrow onwards or do you mean from over the top of the N Pole?

Hi Rob. The warming has begun and the rapid phase starts 22nd with the SSW and technical wind reversal due around 28th (current blend of solutions). Most modelled Strat profiles now show displacement only up to D15 but a full split has come and gone so might reappear.

Now let’s drop down to where all this matters. Downwelling to a tropospheric response (blocking, etc) would be from about 10days beyond the reversal so around Jan 8th so outside GFS although inside EC46 for instance hence why UKM might be quite confident of an Easterly January. The other crucial uncertainty is where any HLB forms and the data I’ve seen suggests a poor correlation between the position of Strat warming and trop HLB so don’t focus too much on where the remnant PV at 10HPa ends up.

My advice to anyone searching for cold stuff is to be patient and remember trying to forecast the weather is about more than just looking at a computer’s headline solution.

Thanks Neil.  Each to their own, and I am confident in my deciphering of the models.  Vive la difference.

UKMO extended keeps the UK in a mild flow of air with rain in the west

This morning's ECM has at least a nice, frosty and seasonal Christmas morning for much of the UK. Here I'll be lucky to see Christmas minima falling below 10c. Looks increasingly probable that I'll have observed more morning frosts in September than December this year. 

January will be completely different IMO. It's a case of much patience required.

I did say the effects of a SSW we’re unpredictable.

An SSW doesn’t guarantee cold weather any more than an absence of an SSW guarantees mild weather.