chris55

ECM op with that mega cold pool on a decent trajectory! Comparing it with the UKMO at the same time id say the ECM is better with the Atlantic low a lot weaker!

One step at a time eh boofer!

Blocking over Greenland?? Well of course there is no blocking over Greenland, the charts are clear on that! There is however a big block developing over norther Scandinavia and its something we should watch with interest, if we can achieve the correct orientation it has the ability to deliver some colder conditions to the UK. Nothing is clear at the moment and the ensembles are not supporting the cold advecting to our shores at present, so nothing is nailed down. In summary no let down "big time" (how dramatic"!) just a case of watching and enjoying the output. If the cold ends up missing us, so what! EDIT and just for reference you do not need a greenland block to develop a colder pattern for the UK

This Artic/Scandi high has appeared from nowhere and has no relation to the SSW thats happening at 10hpa in the coming days. So for me at least the lower strat pattern is being troph led and the warming at 1hpa is yet to effect the troph. I'd put the deep FI troph PV revving up down to climatology rather than any link to the Strat!

Im thinking we have quite a few ships we could possibly board, so to speak, and as yet no model has a clear direction with regards to this Arctic/Scandi high and where things will ultimately end up. Just look at the differences in how the three models handle the high out east at 144 GFS UKMO GEM

This cold pool looks excessive!! GFS probably overdoing things, but all part of the models finding the correct pattern, and if the GFS 12z has it right ill eat my hat!

Thats a serious swing from the GEM op, just highlights the volatility of such a pattern.

I do like a black hole anomaly!! And that a nice place to have the centre!!! Solid high lat block there!

Some really fascinating output from the ops at the moment, this Arctic/Scandi high is causing some inter run fluctuations. The differences between the 00-06-12z GFS are quite big even in the mid term. At 120 we are getting some nice southerly lows, but losing the prospect of the early arrival of the cold pool However by 213 the UK is freezing and that cold pool to the east is just monumental!! UKMO ramps up the Atlantic low at 144, but still loaded with potential going forward with the high holding its latitude and a nice Italy low in place This Scandi/Arctic high really has appeared out of nowhere!!! I cant remember any means or anomalies picking it up a few days back!! Just shows how things can quickly evolve when it comes to the NWP.

ECM 00z ens, that one outlier from the 12z has gained some support and the control goes very cold in the extended.

Heavy snow moving in from the west

Cold pool makes it at day 10, chilly!

Centre of the holding steady (not sinking) And now the Azores ridge has been squashed ahead we may get a decent undercut.

GFS 144 good shape to the Artic high incoming, question is how will the Azores ridge and Atlantic low interact

GEM lands that mega cold pool perfectly on the 00z ECM very different keeping it way way to the east Even though ECM takes the initial cold pool away to the east a slower evolution could well develop another attempt into mid Feb. really interesting output for sure

ECM 12z Deblit spot the trend setter .......

Bit late catching up today. If we take how the models have evolved the pattern in the last few days id say we have a "chance" of some cold air heading our way. How the Atlantic vs the block is modelled in the coming days will be fascinating, impossible to call either way. History and "our luck" would say the cold will not back far enough west to give us a meaningful cold spell, however while these synoptics are in play the chance of the "big one" are increased, and god knows we will get lucky one of these days and all the building blocks will come together and deliver that snowfest most are watching for. Should be a fun time watching how things develop, plenty of ups and downs im sure.

As others have noted very close to a technical major SSW on ECM winds at 10hpa 60n down to 0.01ms at 72h , and may well reverse around this timeframe somewhere (The met office define it as major if the winds reverse). More of a technicality than a huge change to what has been forecast but still nice to officially get a major warming.

ECM 12z....Trends in the mid term good, eventual longer range outcome poor, we need to hope that this pattern will evolve over the coming days in the 6-8 day range. 168 ....promising 216....underwhelming, though the building blocks are there earlier on, we just need a more robust southerly element that can break through meaningfully into Europe.

Now that's more like it! We start to get the elusive undercut at 168! But as ever these are just the op runs "toying" with the new signal.

Some trough disruption at day 7 on the GFS 12z, it seems to me we are now tentatively trying to pick out the next phase of the pattern from the ops, this mornings ECM and the GFS 06z both hinting at a pressure rise to the north east as the jet digs south east in the mid range. 00z ECM Though UKMO quite progressive on the 12z Certainly some interest to be watched, but very early stages. Some favourable background signals though. Lets hope the ECM 12z continues its theme from the 00z.

Hey chino what is the difference between a wave 1 and wave 2 break, is it simply geographical location?

Ok thanks for that nick, I'm still getting my head around how the strat/troph interact and still learning.

ECM with a hint of potential this morning, as has been mentioned. Also a split in mid strat developing at 150hpa now I'm not sure if this is a result of the trophespheric pattern effecting the higher levels or a case of the disturbances higher up influencing the mid Strat which in turn is effecting the Troph. (Or it may just be a coincidence?) But you can see the correlation with the ridge developing on both the mid strat and troph.

Just a quick comment regarding the strat and those 10/30 hpa charts that have been posted in the Strat thread that look so impressive regarding a warming. here The warming has been well forecast for at least a week or more now and the (near) SSW (probably now going to be defined as a minor warming rather than a major one, by the met office, because the winds at 60n don't quite reverse) is as we expected. Yes a good warming up there, but not such a good result, a displacement of the vortex is the end result from the warming, and unfortunately the displacement does not look favourable if its a high lat block in our area you are after. A split in the strat vortex would be much more interesting, but alas that is not how the strat pattern is responding to the warming. This summary is based on the initial warming and there "might" be some more developments in the strat as we go forward, but the initial warming, that those impressive looking spiking charts at 10/30 that were posted in the strat thread indicated, are actually just showing the expected spike, which as described does not split or displace the vortex into a favourable position for subsequent down-welling. If i post some charts for reference, You can see that massive warming heading towards the pole, Which is a major departure from what was there before But the end result just displaces the vortex from the pole to the lower latitudes and as stated it is displaced southwards over north Europe, so if your looking for a direct correlation between the strat and the troph its not looking ideal! We then get the second warming (wave 1, we really need to see a wave 2 injection to split things) Which again results in a slightly displaced vortex, but nothing thats screaming a good troph (troposphere) pattern if it was to down-well. So in summary, even though we get a good strat warming the resulting stratospheric pattern in not looking that good for our region if a direct downwelling is to effect us and result in a colder pattern. There is some argument that the displaced vortex may ease the canadian troph PV and perhaps could encourage a colder north west/north flow for us but we shall have to wait and see.