Daniel*

February 7

5 minutes ago, WYorksWeather said:

Even if that turns out to be correct, that would still leave any impacts slightly later than in 2018, and the Northern Hemisphere this year is far warmer overall than it was in 2018, so we have less to work

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

February 7

7 minutes ago, feb1991blizzard said:

Look what's here again,

A great example of QTR.

February 7

1 hour ago, WYorksWeather said:

At best, the reversal will happen about two weeks later, if it happens around the 18th. After the usual lag, that would put any resulting cold spell, if the SSW were favourable, into early March. At that point, you need something absolutely extraordinary to deliver. -5C 850hPa won't cut it - you probably need the -8s or even -10s and lower. Which brings me on to the second issue.

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.

February 7

44 minutes ago, raz.org.rain said:

this certainly seems to suggest that there's no guarantee of cold arriving our way...

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.

February 7

27 minutes ago, Lukesluckybunch said:

Totally agree still a big southerly influence at 216!

Southeasterly a distinction there…

February 7

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

February 7

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

February 7

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

February 7

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.

February 7

2 hours ago, Downburst said:

There is the North Atlantic and the South

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.

February 7

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.

February 7

35 minutes ago, WYorksWeather said:

Depends on what you mean by the North Atlantic. The definition used by Climate Reanalyzer is actually record warm at the moment, by a large margin. In terms of locations, our immediate coasts are not that anomalous, but as I showed in my previous post, the whole of the North Atlantic is about 0.2-0.3C above the previous record for the time of year and about 1C above the average.

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.

February 6

45 minutes ago, Don said:

Down to warmer than average SST's?

Unsure about that the North Atlantic is actually pretty close to 1991-2020 average right now, it was freakishly warm last year. So I wouldn’t expect westerly winds to be much milder. Much above average SSTs are seen in subtropical Atlantic off Iberian peninsula and down to NW Africa, more southerly maritime flows are exceptionally mild.

Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5032262

February 6

45 minutes ago, Don said:

Down to warmer than average SST's?

Unsure about that the North Atlantic is actually pretty close to 1991-2020 average right now, it was freakishly warm last year. So I wouldn’t expect westerly winds to be much milder. Much above average SSTs are seen in subtropical Atlantic off Iberian peninsula and down to NW Africa, more southerly maritime flows are exceptionally mild.

February 6

2 hours ago, Froze were the Days said:

Last time that happened other than the induced SSW of 2018 was back in Feb 2012 and even then the real cold only got to the east of London and a stalled front from the Atlantic dumped a bit, I think we're really clutching at straws and even then we'd probably get a short wave develop over the Norwegian Sea or something which usually crops up to put the Siberian Express on the buffers.

Not true..

February 6

The refusal of low to ease or drop south is quite something 72hrs > 120hrs, it even goes north it almost appears to go against the laws of physics with rising pressure to northeast. Some of most frustrating output I’ve ever seen.

February 6

We really should be seeing better here, at day 3, polar jet deflected well south and yet lows are meandering around our vicinity, sums up our luck this winter though - totally nonexistent.

February 6

Little consistency today the earlier GFS runs veered the flow from continent. Faith in NWP reaches rock bottom...

February 6

12 minutes ago, weirpig said:

Crikey quite a shunt south on the Arp

Something not right there with snow line near London uppers are positive.

February 6

GFS back with E’ly and height rises to NE into early next week, UK cold pool developing still possible in mid February. The NWP is having a nightmare.

February 6

1 hour ago, Geordiesnow said:

chart you posted of course won't verify like that but as with the recent plume which bought the record breaking January temperature over Scotland

The affected areas of NW Scotland were under 6-8C 850hPa temps which were far from record levels, they were much warmer further SE winds were coming up from tropical Atlantic, record warm SSTs it’s likely this played a major role and very strong winds were observed allowing for significant foehn warming.

February 6

Robust signal for retrogression to Greenland we want to see it get closer though.. the winter is over posts do not stack up with highly amplified northern blocking guidance like this.

NAO/AO the AO is trending significantly -ve

February 5

Temperature anomalies from the latest GloSea forecasts for the week commencing 12 February. It shows cold air over the UK and deep cold residing over Scandinavia. GloSea is the seasonal prediction system developed and run operationally at the Met Office.

This is from the Met Office blog:
“ Through to early March, there is increasing chance of sleet or snow, especially in the north and east of the UK with greater than normal potential for disruptive snow. The specific locations wintry hazards will become clearer as the lead time decreases.”