Model Output Discussion - Spring Has Sprung

[Ali1977]

Prepare for some 12z upgrades - can feel it

[blizzard81]

 Ali1977 I'm thinking more likely tomorrow morning. 

[Ladyofthestorm]

 Badders potentially yes 

[swfc]

 Ali1977 if it's in your water Ali id contact your Gp.

[swfc]

 Ali1977 possibly but clocks ticking Ali.

[blizzard81]

Nice mini upgrade at 6 days from ukmo compared to this morning's for the same time. Nice little high pressure cell sets up just to the north east of Iceland and a much better looking northern hemisphere profile. I'm expecting bigger and more profound upgrades in the morning. 

[Uncertainty]

To be

Or not, to be

 

[Ice Day]

The GEM at days 9 and 10 looks really good

 

Then we have the GFS at days 9 and 10 - yikes

  

Then the UKMO at 168 is excellent

Well, if the ECM backs the UK and GEM, game on.  If it backs the GFS, oh dear!

 

 

Edited February 11 by Ice Day

[Ali1977]

UKMO GEM great - GFS hopefully very wrong!! 

[Uncertainty]

@blizzard81 @Ali1977 

Feels like we’re the last remaining contestants on some cruddy game show called winter 2023/2024… But the gem and UKMO say we live to fight another day! 

[Drifter]

Very interesting short range changes on UKMO. 

Are there any educated guesses why GFS has really ramped up the PV seemingly against all background signals? 

[Ali1977]

 Uncertainty we just need a better set of GEFS and a ECM to match now  

[Ice Day]

 Drifter Completely unscientific, but probably just the GFS doing GFS'y things?!  Be interesting where it sits in the ensembles, probably a very big outlier!  For what it's worth, the GEFS mean at 150 is improved vs the 6z

[blizzard81]

 Uncertainty . Nice one mate. That really made me laugh . Yep, ukmo was only going one way after that mini pressure cell develops at T144 to the north east of Iceland. Great locale for that to take place. 

[Met4Cast]

There’s currently no real sign of anything colder reaching the UK in the next 2 weeks. I think we can *probably* write those off. 

There is the potential for something colder late Feb/early March on the basis of a downwelling SSW, extended ensembles do show a switch to colder weather albeit not very confidently at present. 

In terms of background forcing, the MJO remains favourable however the AAM does not, two different forcing coming out of the tropics/sub tropics makes forecasting more uncertain & nailing broadscale patterns difficult, especially when you factor in an increasingly unstable polar field (SSW). 

[raz.org.rain]

 Met4Cast it would appear that we're getting a somewhat clearer impression of how an SSW will impact lower latitudes, and it seemingly isn't good news if you want cold in our location. Regional factors such as a strong jet just go against any incursion potential. The safe bet would be to assume that the cold incursions strike the northeastern US instead. I'd imagine we'd get more of the same of what we've already got.

Added this tweet as it includes some charts to support this assumption.

 

Edited February 11 by raz.org.rain

[Metwatch]

To me it seems there is a sort of battle between different drivers, perhaps the MJO vs the AAM and in general a strong zonal polar jet. There are attempts of heights rising to our north / north east albeit quite weakly, but the returning heights over Iberia would very likely overpower any ridging that attempts to form to our north, and so the jetstream pushes through and brings further low pressure systems through the coming week.

 

The best case scenario would be something of a UK high such as the latest GEM shows in the mid range below, which would be much needed following further recent flooding, but I can't see that being too likely at the moment.

 

No one can say with any certainty if the upcoming SSW will deliver sufficient northern blocking lower down to bring anything wintry to north west Europe, and anyone who claims it will is just spreading misinformation.

Edited February 11 by Metwatch

[RJBingham]

Snow free winter, still on.

 

[Purga]

Virtually zero cold runs at all for at least 10 days

Only a faint fantasy of a snow row at the far end of FI. You can bet your bottom dollar that'll soon disappear nearer the time.

It's wearing very thin hearing from some friends of mine in Finland, saying what a brilliant winter they're having. Not stop freeze virtually since November with many times below -20C for days on end & when it warms up it snows in buckets!  Anway, good luck to them  - anyone fancy emigrating? 

 

[Stephen W]

Very poor set of 12z ensembles from GFS. Mild pretty much throughout and on that basis we are on course for an exceptionally mild CET and could well be near the top for warmth. Hay ho, good riddance winter 23/24.

[Allseasons-Si]

 Stephen W

you should wait...

12z gefs mean v's 06z

850's on the descent towards months end..

Edited February 11 by Allseasons-Si
typo

[Ali1977]

Great mean - winter is coming ️️

 

Some of the better ENS here 

Edited February 11 by Ali1977

[Mike Poole]

ECM showing a much more positive evolution out to T192:

[WYorksWeather]

In terms of prospects for the next couple of weeks, here's my take. The GFS ensembles are poor, no doubt about it.

There is a cooling trend beyond day 10 as others have pointed out, but the -5C isotherm on the mean is not cold enough at this time of year. We'd need one of the coldest ensemble members in the set to verify to achieve anything. Of course it's not impossible - it breaks no laws of physics. But based on historic trends this winter, and the number of cold spells beyond day 10 we've seen fail to occur, or get downgraded to just a couple of slightly colder than average days, would you really bet on it at the moment? I really wouldn't, frankly.

Worth having a look at day 10 spread charts - the key uncertainties for our locality are over Greenland and from the west of the UK through to the mid-Atlantic.

By day 16, uncertainties are of course much higher everywhere, but the models really don't have any blocking potential nailed down, with spread values of 15-20 dam over Greenland and the mid-Atlantic.

I think there's still possibilities into the latter half of February, but Murphy's law applies here - as long as there are those mild outliers in the ensemble, I'd be loathe to discount them.

We also have to consider the overall pattern for the month, it's now looking highly unlikely that February will come in anything like the long-range forecast models have been showing. It would take an almighty cold spell in the last 10 days to achieve even an average February, let alone a below average one.

I will follow up with more analysis later when the ECM ensembles are available.

 

[Allseasons-Si]

 Mike Poole

Yes Mike,...looking good here at 216.