Model Output Discussion - Spring Has Sprung

[WeatherArc]

Nice to see CFS playing around with some high pressure scenarios for this summer, just for fun at this range but after the amount of rainfall we had in 2023 think we could all do with it.

 

[feb1991blizzard]

Game over winter, even though nearly a full house.

[Don]

6 minutes ago, feb1991blizzard said:

Game over winter, even though nearly a full house.

Hmm, 21C probably more likely on that date than what the model is showing and I'm being serious!

[Allseasons-Si]

Last one from me

the control is heading the same way that the gfs was heading with a northerly plunge

18z gefs mean v's 12z 

gefs ens trending 

i will keep the white flag on the mast at half full for now

 

[Ali1977]

Winter still coming 24/25 Feb ️

[daz_4]

Transient snowfall at best with those uppers in late February.

[KTtom]

 daz_4 indeed, you are looking at nearer -10 uppers required from a northerly that late in Feb / early March for lowland lying snow. 

Edited February 13 by KTtom

[RJBingham]

Chance of a frost from GFS, in deep FI though!

 

[KTtom]

 RJBingham its an outlier

[RJBingham]

 KTtom GEM agrees with you  

[Alderc 2.0]

 WeatherArc let’s hope so but they’ll be those after a week of sun crowing we need the rain. .

Edited February 13 by Alderc 2.0

[winterof79]

If we're cherry picking 850 charts.Myth regarding needing -10 uppers for lowland snow End of Feb.

And for balance

Edited February 13 by winterof79

[Ali1977]

 winterof79 That’s a pretty solid mean day 10 onwards, maybe just coming into view on the ECM too!! And you are correct ref the myth of needing -10c uppers in late Feb, no idea why people make this stuff up The Sea is at its coldest point into March which helps too, and why it’s easier to get snow Into March vs November and even December!! 
 

Winter still looks to be coming 24/25 Feb ️ and we have a major SSW so expect some craziness into March too 

Edited February 13 by Ali1977

[minus10]

 daz_4 they are 2m

temps....here's the uppers..

[daz_4]

 minus10 I know. I wanted to show how those uppers translate to surface conditions. All I'm saying is that -4/-5 uppers from NW flow in late February is nothing spectacular. Yes, the snow can stick for a little while, especially at night but will melt quickly during the day.

[Dennis]

Good day to all

hmm i didnt see that much on the charts last years

10hpa vortex core over UK

[bluearmy]

 daz_4 of course it’s more complex than that but in general I agree with your point. We can’t micro analyse charts at such a range - there’s no point. 

[bluearmy]

 Dennis yep dennis - even on a gfs op at such a range that’s unusual.  It doesn’t hang around on its way towards Iceland but it does leave a broad w euro trough behind lower down. 

I’ve been pretty impressed with the gfs op in the upper strat this winter. Of course you can’t look at one run in isolation and need to check them all so you get a handle on likely continuity. 

[Penrith Snow]

Looks like Andy's Feb 98 Arctic North Westerly revisit is coming into view.

Pattern matching is limited but has its uses and I think a cold spell from the North is a good bet for late February.

How cold and snowy is up for grabs but Shetlanders who have had a good winter anyway are in for more fun.

Andy

[Penrith Snow]

 bluearmy I have been impressed with GFS full stop, repeatedly terminating new born cold spells while ECM always pointed to a 1979 revisit.

[bluearmy]

 Penrith Snow because the Atlantic has generally won out fairly swiftly, the gfs will usually win the model battle as it reverts to type !   on a very broadscale level, gfs has looked good but closer analysis of the heights would reveal that it’s probably no better than any of the others.   

[North-Easterly Blast]

 Penrith Snow I do not think that at any point this winter any forecasting model ever pointed to a 1979 revisit.  Remember for its general weather pattern, winter 1978-79 was in some ways a bit similar to 1962-63, though only that the depth of cold was not as severe.  No model this winter ever suggested that anything on 1979 lines was ever likely.

[Uncertainty]

Generally it’s been quite a good morning for building the momentum that the 18z started last night and that the GEFS have been touting for quite a few days e.g a big scandi trough - AR combo in the 11-15 day range. 
The gfs op is very similar to last nights permutation 

Beautiful chart btw

The mean is very much on the same page and consistent over a few days now

Now the Nw heights aren’t currently progged to hold but, crucially, the euro trough is so we do have the opportunity to Build heights over the top towards scandi, especially if the strat  pv goes the other way ala gfs op.

Can’t think of the last time that happened mind so hardly a cert. Obviously any cold, blocked or even half pleasant scenario needs to be taken with a massive bowl full of sea salt after this winter’s modelling shenanigans.

The ecm, not that I trust a pixel that it pontificates these days, has conjured up a scandi high with a U.K. trough deconstructing against it. Make of that what you will.

The gem is settled for a good portion of its run than barrels in a U.K. trough. Notice the very -AO and Atlantic profile - certainly not standard fare and you could see a big northerly not long after 

 

The mjo heading to 4 is a poor portent to me. I find it is one of the strongest indicators of a strong Atlantic. The nature of the strat weakening feels odd to me too. A very brief reversal and a quick reconstruction didn’t help us in late Jan did it. On the contrary.

So there we have it. A rare 0z set that doesn’t completely vanquish cold prospects but instead teases and tantalises like it’s rowdy party time brother from the afternoon. Do we believe it? Probably not. Energy levels for the chase are seemingly at an all time low after let-down has become the norm this winter. 
 

This is the final chase for me. I’m already craving the arrival of mid/late spring (incidentally my favourite season in Cumbria - our dry season). If this quest fails unvaliantly - probably after the 6z haha - then I’ll be searching for south westerlies not sorrowing over them.
 

Are you in then, for one last ride, for old times sake? 

[Mike Poole]

ECM clusters this morning, with some earlier interest (surprisingly) in the T192-T240 timeframe:

Clusters 1, 2 and 6 all show a ridge sufficiently to the west of the UK to bring in cold from the north by day 10.  Clusters 3 and 5 edging that way too, just cluster 4 has the ridge initially through the UK and a mild flow.  

T264+:

Cluster 1 really set apart with the big high lat block over Greenland and northerly winds, trough in Europe.  The others are a bit nondescript by comparison, 5 and 6 showing some interest in a northerly too.  

[Mike Poole]

GFS 0z is a good run for cold, and it is worth noting the zonal winds profile:

Very much going with the double dip in zonal winds, with a deeper plunge about a week after the initial SSW - this was evident on last night’s ECM 46 as a strengthening signal and is worth watching.