Mike Poole

Hi Big Snow, The high pressure is first building towards the UK and then north as a result of the first SSW, only then does it look like heading to Greenland probably forced by the second warming. Sooner it gets it's skates on the better, for this upcoming cold spell to really count.

Very happy with the ECM ensemble mean But we've seen two op runs that highlight the risks that we face, the GFS 0z taking the High too far north, and the ECM 12z leaving the block too close to the UK so the cold air goes south. And, of course, all the other runs that say Game on! Should we be worried? Not today, let's see what tomorrow's runs bring.

We'll I don't but it was the first chart from a major model that looks like a wobble, but hey ho, the T240 looks just fine, high looks like it's off to Greenland, maybe a delay to get the cold in though. But different, to the other output today, I think.

Is this a bit of a worry at T216?

With the ECM at T168, it's coming, just not as fast

The strength of this block across all the output is immense. Look at the GEFS mean at T228 1050 contour there on a mean chart at this distance. Probability plots also give indication, probability of >1030mb at the same time: It's like (for this GEFS suite anyway) a nailed on retrogression. And where's the Azores High? Absent, presumed missing! Onward the ECM...

Welcome to meteorological Spring! T264

Stone the crows, this run is mental! And getting earlier too! The main interest in last week of Feb rather than into March. 850's:

How many epic runs can we expect from the 12's? I wonder if we enter a bit of a limbo period now, with the basic pattern pretty well set (barring any downgrades or upgrades), but the next questions such as where and when will experience snow not resolvable until later in the week. So it's a question of continuity of signal, and it's certainly still there in the ICON at T96, maybe pulls the E'ly in a little quicker than the 6z run, not much in it:

That's interesting, and certainly one of the two biggest risks, but I think it may be the lesser one. My gut feeling is that the second warming in the strat will only strengthen the block and the bigger risk is that the block will maybe drift too far north, GFS 0z run exemplifying this evolution? Having said that, there's very little in the output today to suggest that either of these risks are significant, quite the contrary, it's just that there are some days to go and things can always change. At least I think the risk of the Atlantic breaking through is negligible.

So, into the GEFS ensemble, here at T252, this thing is practically nailed on now, you can tell your mum!

Agreed. Zonal!

Holy schmoley! If this happened I'd wet myself, but it would freeze! GFS T264:

To think I described the GFS 06z as oozing epicicity, there are no words to describe this one, not even made up ones! Here at T216:

Of course, mother of all easterlies, d'oh!

No idea where this run goes from here, literally.

These Easterlies are really like pulling teeth - except the tooth never comes out, but the pain continues nevertheless! But we're getting there, GFS looks a good run to me, here at T138:

Today I think we've flipped from looking for ways this can possibly go right to looking for ways it could possibly go wrong. As I said in my post at lunchtime, the SSW is delivering blocking in more or less the right place, the second warming should boost it higher, so while the risk that the eventual destination is a UK High diminishes, the possibility of it going too far north maybe increases a bit. But the 12z suite was by and large good. So to the 18 z's, first out the trap the ICON, and it is looking well OK at T81:

I think it's worth posting the GEFS mean at T240. Obviously that's 10 days time but the point is that following the SSW this is a very plausible evolution.

OK, putting the GFS 6z to one side, where are we now? Some kind of easterly flow can be banked, I think. But will that be a weak flow with the High too close to the UK for significant snow, or the true Beast from the East - from the model output both these options are most definitely on the table. Enter the second warming in the strat - happening round about now: We know that a SSW promotes high latitude blocking, and 2/3 of the time this results in cold for the UK. However, we now know also that the main warming of 11/2/18 HAS put a block in roughly the right place for UK cold. It seems to me a reasonable assumption that the second warming can only serve to strengthen that block - leading me to conclude that there is now a high probability of a really significant cold spell. Time will tell! Fascinating model watching - best since I joined Netweather.

This GFS 6z run just oozes epicicity! Here's the T288 chart And the uppers - wow! First day of Spring, anyone?

WOW, looks like even the zonal biased GFS is on board the massive long-draw easterly train by the end of the run whatever next?

And straight on cue, here the Ely comes All roads lead to cold?

Where do we go from here? My starter for 10 is the low 1500 miles east will strengthen the block, the low west of Ireland can only go under, the result a mega Ely - again. Could be wrong mind!

GFS just starting to take the High north of UK by T132, later than ECM, but given its zonal bias I don't see this as an issue, model at T 132