Ladyofthestorm

The polar vortex looks at best uncomfortably unstable. It's coldest parts always wanting to split . It looks ragged and happy to spill contents. Watch the significant cold to the East It's not exactly screaming mild, wet and stormy for our Atlantic shores either. Maybe some cold PM air from NW, transient bringing wintry showers to Scotland. Not convinced the mild conditions will last long.

It's not truly zonal long term either. The PV looks still very fragmented, ragged and fragile and I know that we are needing to look east and not west for weather in January. We have had a continuing wintry theme here in December. One mild day and that's been it! And we live right on the cusp of the Atlantic influence.

Agreed, I think the GFS is closer in resolution than the EC.

The teleconnections are not exactly screaming mild Atlantic either. AO staying neg and the NAO negative to neutral. Not exactly the Atlantic flip. Yes chances of a white Christmas for the south of UK is very slim , but further north every possibility . Looking ahead anplication of that problematic deep low, but look how it backtracks and moves west over the Atlantic. So no clues. As yet. The ensembles are still anyone's guess even mid term. Certainly don't put away the sledges just yet.

Hi Matt So the Greenie High later on the runs is just one possible scenario and the ECM hasn't picked up on the decoupled Stratospheric / Tropospheric conditions,? Usually GFS is good at picking up the blocking trends and given conditions right now in the arctic it wouldn't surprise me.

I'm reading a significant amount of mild ramping . We have just had our coldest early part of December since 2010 and I do not see anything in any charts that suggests Atlantic driven weather for the rest of it. Yes mild incursion, but it is brief. Christmas day away from South of England and Wales looks potentially a white one, Indeed the GFS is beginning to come into a more reliable timeframe now A clear -10 850pha across Scotland and Northern England from a Greenie High. I would expect snow showers from this immediately away from coasts and to higher ground as a minimum. The ECM follows similar trends, maybe not as dramatic but nonethe less same idea and origin. Now look at the ensembles for my area , yes we are in the north but we are right under the influence of the gulf and Jetstream...... And it gone on holiday. If anything the GFs and GEFS want to head back to the factory reset button of mild Atlantic late in the runs. However look at these . Mild outliers in F1 well above the mean and lots of runs much colder! Last time I saw a run like that for actual Christmas day was 1995! No thankyou , we had cold turkey because of a powercut due to ice and -24c in Braemar. That leads me onto the teleconnections The AO and NAO heading very slowly back to neutral. That is not the same thing as positive. And certain no medium term indication of a return to milder Atlantic driven weather other than for Monday. That negative AO for December is quite incredible. It's going to take a while, if at all for the polar Vortex to recover. Any recovery doesn't last long. I've not idea what the prospects are for a SSW but look at the highs constantly chipping away at it... Big wavy wobbly unstable , weakened. So I'm not convinced it isn't all over , indeed we aren't playing football, so let's just watch these fascinating charts and runs play out. The game has just literally started. Interesting times are afoot!

That looks one heck of a fragmented polar vortex with arctic heights not far from the pole. I would need more persuading of a significant return to Atlantic driven storms.

Looking at the ensembles this morning for my area and the NAO/AO ensembles yesterday and the blocking plots from NOAA I suspect that any thaw for us will be short-lived. We have a milder spell next week... Briefly , then another reload just literally before Christmas. Longer range, the devil is in the detail, could be a cold dry ( I think that's a GEFS outlier ( blue line post 7 days) with cold 850s but 1040 mb or snowier out all the rest of the models. What I did note is that there is definitely less uncertainty in the models longer term , and less spread of the individual runs in Fl, that we should watch as that's an indication of non Atlantic driven based weather. Also note the very bedraggled polar vortex.. we don't need a SSW for colder weather doors to open. Certainly we can see our Atlantic doors are not wide open. It's been the coldest December easily since 2010. The trend is your friend and I think it has alot on common with 2010. So definitely see how this pans out.

Not convinced that mild will be anything other than transient ( maybe a green Christmas). The AO and NAO are staying strongly negative and slightly negative to neutral respectively on the GFS runs. That huge area of high pressure isn't going to just disappear overnight. Looks like it might migrate west.

Seeing many perps pick up and what I thought too. GFS post 180 hrs is struggling to keep the colder air seen on both the 18z and 0z . However this model in particular is really bad for putting Hannah t back to Westerly based configuration when things become uncertain. Looking more closely at the ensembles, it's suggesting the GFS operational is indeed running at the milder side of the runs. I suspect a huge backtrack by Saturday and us locked in cold until next week.

I won my bet at 1155 pm last night against my hubby that the road would be white by end of Wednesday. £40 is mine. Such a sour grape loser as he was so cocky that he would win it Banking on a warm road surface. Lol He didn't bank on Graupal falling from the heavens in a single snow shower. But anyway, GFS is Fl hrs is heading back to mild stuff, as 18 z and 0Z as already noted as happened before ignore that, it has a tendancy to drop colder signals and intiate a milder westerly signal as a bias. So before everyone throws the sleighs and snow shovels back in the cupboard hold your nerve. The signals for medium range Nly and Greenie blocking as still very strong.

14.5 C in morning 18 C after the wood burning stove is lit in the evening

Nah don't believe in sods law. For info the NAO ensemble looks to stay negative for the next two weeks. Just like 2010! A repeat performance anyone?

And here my hubby took the total Mick out of me this evening and said that he looks forward to the day after tomorrow weather! PS I have a £40 bet with him that snow will be lying on the road by Wednesday!

So synoptics and models ponit towards a lengthy cold and potentially snowy situation. I can't see that Greenie high relinquishing it's grip before the third week.

I did ponder on the thought would that produce that phenomena lake snow affect as there is alot of moisture hitting some verty cold dry air . Especially so later on. One to watch I think.

I'm.trying to remember who told us to get the cold in first ... Chino maybe ?

Is this the beginning of a PV split without a significant SSW?

Definitely a long game on this one for cold lovers. Still very strong signals for settling down beginning of December. What happens after that is anyone's guess. The scenario of that high pressure over Atlantic ridging up to Greenland and letting the Nly gates open is plausible like we saw in the GFS yesterday. Watch for that scenario returning at 240hrs! It's done it before.

Hmmm agree with you on that.. with exception December 1993 and 1995,

Ian Simpsons analysis of the current synoptic setup and the analogue years of 2001 and 2005 give me much hope. Later parts of December 2001 was particularly chilly affair with the north of Scotland having a rare white Christmas. The cold spell lasted for nearly 3 weeks and well into January . Winter of 2005 was relatively mild little snow but very windy... Until late February when the north finally opened up and we got a proper dumping of snow.

Thankyou. Looks like a very strong jet.but a very wobbly one. I think it will cast a few surprises . Going to be an interesting winter!

I'm still trying to fathom exactly what it is? I can't see any clue other than a very strong jet stream.

I'm surprised winter 2017 to 2018 hasn't been mentioned. The only winter we had here on the Outer Hebrides to have snow lying on ground every month. November to May. Not sure what year to compare it by but the trend was ridging high pressure in the Atlantic riding up towards Greenland letting Nly air flood south. Seen something similar this year.

It's not going anytime soon!