Harsh Climate

I was a bit worried for a minute, the angle of attack from the Atlantic, but we get just enough WAA early doors to sufficiently inflate our blocking high. Also advantageous is the low to the SW Greenland pumping up the WAA clears just about far enough north (left of Greenland) and weakens enough not to put a spanner in the works and displace our high back south and east. Excellent run, much improved on 6z.

The low to the SW of Greenland is much deeper on the 12z compared to 6z, sucking in a lot more WAA which should really inflate our blocking high. Looks a big upgrade compared to the 6z this does.

Looks very good to me

On Ecm it is here: Thankfully the low goes up the left hand side of Greenland , rather than into our block giving us a peach of a run late on. Thanks for the explanation, That confirms what I was thinking.

Do you reckon how this low near Greenland reacts with our blocking Atlantic high around 180h is of greatest importance, or am I placing too much emphasis on just a small part of the jigsaw?

The Icon looks quite different to the UKMO and ECM at 180h, like it or loath it probably won't happen anyway! 10 bags says GFS 12z will be quite different; )

It looks like it would get chilly from the east if the ICON was to go further, with disturbances popping in from the south and west turning to snow once it hits the cold air. Not bad at all in my opinnion

Before the GFS 12z trickles out this the key area of interest to me. After 180h Most models are now in agreement that we get a large Atlantic block developing with much colder air about to drop into Scandinavia/ Northern parts of Europe. This low pressure is the deal breaker in my opinion, if it follows the black arrow and sucks up SSW western side of Greenland we should get a perfect Greeny high. Follows the red arrow and we get a high perhaps in the wrong position and with pressure against it, from the top left side which we don't really want (especially at such an early stage.) Could eventually cause high to topple or milder air to filter in from the northwest while deep cold passes around the southeastern corner of UK then west into Europe.... Obviously, it is too far out to be coming to conclusions at this early stage but I would rather get a good trend going to start with, than having to chase and rely on 2nd or 3rd attempts at the cherry while winter slowly passes us by.

To be fair it has been brazenly obvious we are heading towards a cold spell since christmas eve! I don't know how anyone failed to pick upon it. The question is how cold/severe will it get and how much snow will we get?? For that question we do not know. Doesn't matter how much waffle or word smithery someone uses, we will not know until T144H or sooner when all models are in agreement. Like Mike Pool was saying earlier, we have now lost the possibility of a full on SSW event (All levels of the atmosphere) with full zonal wind reversal , instead we are looking at a weakened PV and PV displacement. With the Canadian warming event and the fact this is a El Nino winter, a full SSW event may not be needed for a major/lengthy uk cold spell.

I hope your wrong mate but certainly a possibility, I would say 30/40% chance of this happening

Thanks. To be fair though doesn't a strat warming usually take 3/4 weeks to be fully felt downstream?? What I am saying it will happen a lot faster this time around due to the other factors I highlighted (Canadian warming etc.).

Yeah we have gone from a split PV with a full reversal to just a weakened/disrupted PV.

It's already happening and in full flow by Sunday! We are seeing an almost immediate impact due to the Canadian Warming and a few various other factors this is why we may not need a full SSW for Cold/Snow Nirvana Mid January, we might just get away with it but we are relying on pieces of the jigsaw coming together in just the right places.

I'm not saying discount the possibility of a more milder Atlantic driven end to run being shown by GFS OP, I'm saying that the run has very little support and is of little value when in its own right has no support from its own assembles and has no support from the ECM. I would even include the UKMO as well as that only looks COLD/BLOCKED from 168h on. The chances of the GFS OP verifying with all the various data and signals at our disposal mostly signalling cold and blocked mid January, is about 10%. If we are to miss out on Severe cold (eventually or get little snow in January it is most likely from our Atlantic block being situated in the wrong position, leaving us dry and reasonably cold. Something like this: Where all deep cold misses us sending Europe into the freezer. At the moment I think we are 70-30 against this scenario and looking more favorable so need to worry!

I would be surprised if the ECM isn't one of the colder members of its own assembles, hopefully have some support though.

Ye definitely on a whole far from cut and dry. I mean though that GFS is nothing to worry about without support from it's own assembles. Looks rogue to me.

I would discount that GFS run highlighted at this stage, little support from it's own essembles, the GFS could easily have thrown up a solution like the ECM in the latter stages.

Good news GFS Op is well on mild side from the 10th, maybe even outlierish from that stage (but not getting into that debate again lol ) West Yorkshire mean close to -4/-5 latter half of the run which is not far off where we need to be, would like a few more perps straddling the -10 line and a few below that in the London essembles (sign of deep cold continental air) but nevertheless a good start to proceedings! Steady as she goes Captain Yeah doesn't get much better than that, at 240h looks just like the last 2 ECM runs!

Yeah good shout, showers all of snow now starting to settle down to sea level in the east

Chart of the winter goes to ECM 240h, absolute perfection!

I would prefer WAA more up the western side of Greenland, than the angle this run and ECM showing but the block should still hopefully retrogress and get there in the end.

Looks similar to Ecm12z does gfs 18z so far

Yeah ya right I was guilty of micro-analysing it, is a great chart really! The trend is certainly our friend at the moment!

I'm not saying it's a bad chart lol. I'm just saying that there are better options still on the table! As much as that chart could progress into something good, it could easily go wrong.

The chart screams potential? I would rather it showed something that produced snow not a dry northerly, which could eventually topple! With what is on offer we want more than potential at that stage. The low to the southwest of Greenland has traveled too far east into our ridge, that will not pump the high up for long! This is what WAA pumping up a Greenland high looks like, not that cold fart of an attempt you highlight! Look at the position of the low.