Daniel*

Clearly if we were not looking at a highly disruptive event in stratosphere, it would be fair to call winter over but as GFS 12z shows while the cold misses us mostly it has a radical influence on upper patterns. Predictability what little of it will be tumbling in NWP. We’ve been thrown a lifeline whether we seize it remains to be confirmed.

Very blocky run with hallmarks of an imminent or ongoing major SSW.

The start of a colder cluster in late Feb in GEFS.

Good demonstration GFS 18z with right amplified pattern how quickly things can change in terms of cold air availability. This is a difference of 5 days.

The UK has not had a real issue with drought for over a decade now in fact it is very overdue a series of dry years, last time it began with dry but very cold winter of 2009/10, 2010 and 2011 were very dry years, then we saw wettest April on record in 2012 and awful washout summer which totally eliminated long term drought. No doubt with extreme heat we have been seeing although often brief, we see the landscape suffer on surface but the bottom line against a wetter backdrop this has softened impacts to groundwater and reservoirs so impacts have not been severe. Summer droughts become severe against a long term dry background as was seen in summer of 1976 after 1975 was also very dry year. If we do experience drought issues/ water stress in summer 2024, I think we need to look to water companies very critically there is no way after all these above average rainfall month after month, there is clearly a lack of infrastructure we need to build more reservoirs to collect this rain water for a growing population.

Your drier summers are not supported by the data. The summers are visibly wetter than 1980s & 1990s the latter especially featured prolonged anticyclonic periods, this has become less regular while we have seen some great summers with notably prolonged dry conditions (2018 and 2022 for example) they have not really been representative of the modern summer. England summer rainfall amount:

Great the timeframe less great!

You say that but Northern Europe/Scandinavia is expecting coldest winter since 2009/10. The deep cold has been persistent in upper Europe, potentially accessible to wider Europe things have just not aligned at least yet. Again an illustration in a warming world… persistent cold anomalies can occur regionally. I personally don’t see the value in looking at entire Northern Hemisphere you need to look at areas with relative proximity to UK where the cold originates to our north and east. I don’t see why for example a very warm Canadian winter means much to us.

As said the AO is already on side, I think it’s a good indicator to a quick response. Much less possible interference and the need to break down stubborn +AO.

It’s possible the trop pattern can be already primed and be a catalyst to major SSW and very rapid downwell they are ultimately related. So I would say the ECM 12z is QTR in my opinion.

Well maybe I’m remembering wrong but I’m pretty sure Feb 2018 split looked very similar to this with one shard in NW Russia and other in eastern Canada. Of course 2018 was not the most durable but the issue I don’t believe was TPV it was NAO blocking becoming too west and retrogressing too much… maybe too much free rein is a bad thing. I think we had too much of a good thing then.

Well this is the chart of winter… the split which appears favourable on GFS, is our best shot of getting a significant late winter blast.

Frankly I don’t know what you’re talking about we have been seeing long drawn southwesterly winds from subtropical Atlantic which are much above average waters. The direction has absolutely everything to do with it, as I’ll say again SSTs are near normal to our west if wind blows from west it wouldn’t be excessively mild.

It was warm in 2018 too when extreme cold was seen. February 2018 actually featured record anomalous warmth in Arctic.

A great example of QTR.

What you say is not strictly true actually with 2018 major SSW given the nature of split it was actually quite a long wait. It’s been known for the big SSWs to have impacts within a week, I think this occurred in Jan 2013 there are other examples too like Jan 2009 both splits a week later London saw its biggest snowfall since 1991. The fact the AO indexes are already on side is another indicator of a potential quick downwell before the end of February I’d say.

I think he is actually pointing otherwise, that’s a good signal same happened in February 2018 split I recall, one shard in NW Russia and then the frigid easterlies arrived. The actual vortex lobe itself does not bring cold weather to UK as waters around us significantly moderate it.

Southeasterly a distinction there…

Now you’re really talking.... GFS 12z emphatically splitting polar vortex.

UKMO definitely best of the lot heights going up and over, but I do not trust this model one jot.

Getting sufficient CAA seems uphill task but yes latest GFS much more amplified to NE.

Well major SSW looking increasingly inevitable some GEFS runs dropping it to -20m/s which is impressive and benchmark of a very powerful event. It could be possible we see most significant SSW since February 2018 event but for the moment a split is not clear, it’s hard to see the vortex truly recovering into spring. I think the spring could be eventful this year just a feeling.

On global scale yes but most of “North Atlantic” is not especially relevant to NW Europe at higher latitudes. Vast majority of that anomaly is coming from lower latitudes. Waters to our north, east and west are not unusually warm therefore the idea all wind flows are excessively mild is false. It’s southwest flows which are very mild and even milder.

Hardly inspiring GEFS but another GFS op on top end from start to finish today. Well there is some good agreement at d10 between ECM and GFS ens perhaps chilly rather than cold at the moment but something to work with heights quite strongly signalled to NE. And a gentle continental flow. I haven’t had a frost in a while. Deeper into FI things become more possible with retrogression signal near Greenland EPS been quite persistent with that opens up more possibilities for deeper cold to be introduced. Overall not a terrible direction of travel but it’s not a fast path to glory, an opportunity for regular night frost to cool the ground, dry with sunny spells offering good useable weather. Then we should be more primed for something of more significance… later than we’d like but beggars can’t be choosers.

Well it’s wrong to call it “North Atlantic” when it goes down to latitudes of equator. That is not the North Atlantic it’s all being tangled into one.