[South West and Central Southern England Regional Weather Discussion]

Very heavy snow in Eastington now (5miles West of stroud!)

 

 

[South West and Central Southern England Regional Weather Discussion]

Light wet snow here in Eastington, not settling, just melting the frost lol.

Stroud, with that bit of elevation looks great @bellanite.

Im surprised TBH as it’s the coldest part of the day.

Edit: Actually is settling a bit now. 

[South West and Central Southern England Regional Weather Discussion]

Showers look to be heading towards the Bristol area? Currently crossing Cardiff.

Also could swing northward as they wrap around with the small feature associated later on tonight.

 

[Model Output Discussion - the cold has arrived]

This isn’t over yet IMO.

UKMO quicker with the initial low allowing a small ridge ahead of the second/spoiler low. 

This keeps the spoiler low out west keeping the cold in place. 

With the NH profile, it kinda feels like dec 2010, when all roads led to cold, even when the Ops and sometimes then ens were scouting out a milder option. 
 

Great model watching
 

 

[Model Output Discussion - the cold has arrived]

37 minutes ago, Kentish Snowman in Yorks said:

 

Yes an uptick in cold options in the lead up to the big day on this morning's GFS ensemble runs.

Maybe a temporary relaxation of the cold before it bites back in time for Christmas?   

That’s a really good visualisation of the situation, looks like this push from the Atlantic may be hardly noticeable! By the time surface conditions have mixed out its back to a colder trend.

I wouldn’t be surprised to see a U.K. high of sorts holding us in the cold throughout with the Atlantic Low being more elongated come next weekend. 

[Model Output Discussion - the cold has arrived]

So part of the Trop PV moves across the globe from east to west, with another cross polar flow setting up on EC 240….

December 2022 going down in the history books at this rate!

[Model Output Discussion - the cold has arrived]

15 minutes ago, Ali1977 said:

Whoop , get in. This will be a nice twist

This looks totally feasible to me. 
 

I was thinking two roads to continued cold earlier, one being the Atlantic ridge (ahead of the Atlantic low) reinforcing heights towards Greenland . As above

[Model Output Discussion - the cold has arrived]

5 minutes ago, Captain Shortwave said:

The GFS control giving this a go too.

The Azores high…normally the game maker looks a bit shy…..

I think we are in the game, at least to some extent till the end of the month. 

[Model Output Discussion - the cold has arrived]

1 hour ago, TSNWK said:

similar to this morning UKM I would day?

 

The queue from the Atlantic looks pretty pathetic tbh! If compared to the energy on the other side of the globe.

Anything beyond day 5 in such a turbulent period should be analysed with some caution either way.

[Model Output Discussion - the cold has arrived]

If these Atlantic lows can disrupt a little and draw up an Atlantic ridge ahead then surely this cold spell has a way to go yet!

When looking at the NH profile, that looks like a decent bet at the moment. 
 

Its either an Atlantic ridge ahead of the Lows reinforcing the Greenland heights, or the lows make a bit more progress and inflate a Scandi high instead.

That’s our two routes to continuing cold IMO.

12zs incoming

[Model Output Discussion - the cold has arrived]

4 minutes ago, bluearmy said:

The high anom to our nw persists throughout. We have a euro high anom to our south for Xmas /new year week but no accompanying slp anom ?  

A low surface temp anom for later in Jan also caught my eye - unusual at such a range - 

Hi Nick, With such an anomalous NH profile, do you think we can use the longer range spreads with the same confidence as in a more mobile/usual winter scenario? Or should we be more cautious than normal with the longer range predictions?  

[Model Output Discussion - the cold has arrived]

1 hour ago, TSNWK said:

agree. I'm seeing west base NAO risk here increasing day 8 onwards how odd to be wishing for some energy into Greenland

Fortunately, the NH synoptic profile is so primed for U.K. cold we are continuing the cold theme.

 

 

 

 

[Model Output Discussion - the cold has arrived]

2 hours ago, TSNWK said:

 an agreeable UKM  - un settled from the north east and looking nicely primed for next weekend, as the over spain is movin eastward.

Where on earth has the trop PV gone!! These charts are super rare!! Canada is visible….not purple :0
 

Surely snowfall will come one way or another with such exceptional NH Synoptics. 

Great times to be in the MOD

The snow WILL come….. 
 

 

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 hours ago, Ali1977 said:

Yep, looks good to me 

Absolute peach! ️ 

We have these historic snow events of years gone by where this exact set up delivers as shown above, they are a rare thing these days and in my 20 years model watching I don’t think one has come to fruition.

Hopefully we can nail this one, long way to go yet mind

[Model Output Discussion. 3/12/2022. How cold will it get?]

3 hours ago, Tidal Wave said:

Blizzards incoming on UKMO 144 hrs.

I think I’ve fallen in love

[Model Output Discussion. 3/12/2022. How cold will it get?]

UKMO

 

1 minute ago, Captain Shortwave said:

The ECM is an improvement, one of the reasons is the the core of the heights are further south towards Iceland, this squeezes the cold pooling spreading west from the U.K. trough.

 

It is also slower and the Azores low is interacting with the upstream cut off low.

If all that energy can get under then it’s a raging easterly! If not then it’s GFS.

Lots to keep us on our toes!

[Model Output Discussion. 3/12/2022. How cold will it get?]

3 minutes ago, Lukesluckybunch said:

But even the ukmo isn't great really..Could still do with a correction south of that low

A few hundred miles either way and it’s either northern France or the north of England on the boundary. 
 

As everyone should be aware these charts deciphering an Atlantic low coming up against a cold block are impossible to get right at this range. 
 

More runs needed. 
 

ECM can not be ignored, and it shouldn’t be also the ensembles are trending tentatively with the Azores low pushing further north, but we need some inter run consistency and solid ensemble support before we can call It. 

[Model Output Discussion. 3/12/2022. How cold will it get?]

10 minutes ago, Kasim Awan said:

Definite trend.. looks more blippy rather than full breakdown.. treading on thin ice now though imo.

The mean does stay below 0c for London though….you’d think with some ppn and (hopefully a southeasterly flow ahead of the low) a fair few would see snowfall at the boundary?

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 minutes ago, blizzard81 said:

I disagree. Time is ticking down with regards to the low. It isn't 8 to 10 days away anymore. Invariably this means there is much less time for upgrades. Talking about the ecm run only of course. 

Why only talk about ECM?

Take UKMO for example!

 

All this debate relates to the Azores low and how it eventually interacts with the cold blocked pattern over the U.K. 

 

Experience tells us these Atlantic incursions often fall short, earlier today BA was suggesting anywhere from Pyrenees to Scotland for the boundary! 
 

More runs needed

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 minutes ago, Quicksilver1989 said:

Problem is you are relying on small scale factors to come into play. The EC at day 10 for example you don't have much in the way of cold pooling to quickly tap into and you have an 1025mb+ high between Spain and the Azores. It would take a long time to get cold from there presuming everything fell into place. What if a chunk of the PV fell into the North Atlantic following an SSW like in Feb 2019.

A lot of winter still to go and a lot of uncertainty still to resolve but given it took so long to get here (with the Scandi high in November), people are just frustrated this has an inevitable feeling about it... but lets see what the ensembles 00z bring.

The modelling of the Azores Low seems to be the trigger here. IMO your confidence in its track at day 6/7 is premature. We shall see, but at this range, surely measured forecasters will await full ensemble support before making a solid judgment? 
 

I’ll hold you to your assumption it will barrel through and bring milder weather to the entire U.K. ,boundary blizzard aside for now - transitory or not.  

 

 

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 minutes ago, Jason M said:

Absolutely, plus once you get into the west based set up with a huge Atlantic low, heights building rapidly into Iberia is almost always the end result. Poor day today but I think it's worth just waiting until the morning as the models are struggling a bit. Heart says the morning runs will look different, but head says that were now just looking at a few days of cold weather with a transient snow event as it breaks down.  

Are you both not seeing the MASSIVE northern hemisphere disruption???? With the PV lifted right out of Canada? 
 

 

[Model Output Discussion. 3/12/2022. How cold will it get?]

1 minute ago, Kasim Awan said:

its a creeping north over time, involving 2 steps forward 1 step back progression

not claiming credit just stating the backlash i experienced for just a simple opinion was unjustified

 

It hasn’t verified? We are all here looking at a very complicated local synoptic pattern coupled with a very blocked and unusual NH set up and making finite judgements on charts at day 7 (the 0c Isotherm crosses England day 7.) My advice would be give it a few days before claiming any victory’s.  

[Model Output Discussion. 3/12/2022. How cold will it get?]

2 minutes ago, Quicksilver1989 said:

The two work in tandem unfortunately.

The outlook may change again but once the EC showed that solution last Friday evening, I was for a long time concerned about that Azores low. If a cold spell can go wrong it will.

After watching the model output since 2005 you can never sit comfortable until no ensemble members are going wrong.

Exactly my point! It’s the modelling of the Azores low, not the African height rises that you should have mentioned. 
 

However I don’t agree with your general assessment of the operationals,  you tend to be to Knee Jerk in your evaluations.

ive been here since 2005 also…..;) 

[Model Output Discussion. 3/12/2022. How cold will it get?]

3 minutes ago, Quicksilver1989 said:

It's a flop

I personally wouldn’t call it flop in the context of the array of options the operational runs have thrown out post day 6.

NH profile still ripe for continued cold.

[Model Output Discussion. 3/12/2022. How cold will it get?]

Just now, Quicksilver1989 said:

This needs to slide under given the rising heights over NE Africa there.

The forcing is (unusually) from the north, so those heights over NE Africa are simply a reflection of the Azores Low at this particular timeframe.