Model Output Discussion - A cold start to Spring?

[Mcconnor8]

Just now, MJB said:

Quite different to the 6z - Atlantic steamrollers in

Snow on the leading edge 

At day 8-9 the GFS OP basically always throws out a completely different solution run on run so not a suprise, next run probably back to how the 6z looked knowing the GFS.

[Mark wheeler]

Oi Oi.

 

Gfs has a north of the M4 event the Gem south . Take ya pick .

Edited March 2, 2023 by Mark wheeler

[MJB]

Slow moving band of persistent snow

[nick sussex]

Quite a different FI GFS output due mainly to the PV trying to move back nw .

The PV needs to hold to the ne if you want heights to hang on to the north.

[MJB]

About 6 hours of persistent snow before the Atlantic becomes boss

[Rain All Night]

The Atlantic low on the UKMO doesn't wash the cold uppers out of southern England:

In fact, all of UKMO, ICON, GFS and GEM keep the whole of GB under cold uppers out to T+168h at least.

Edited March 2, 2023 by RainAllNight

[Snowy L]

3 minutes ago, nick sussex said:

Quite a different FI GFS output due mainly to the PV trying to move back nw .

The PV needs to hold to the ne if you want heights to hang on to the north.

Looking at the strat there is zero indication of the PV trying to get back into the Arctic or even reforming in the first place. In fact we still have a strong high pressure in the Greenland/Easy Canada region so it's a bit odd the GFS is so desperate to move the PV back to a normal position when things are still the opposite of normal up above.

[winterof79]

Thats as far as you go Atlantic before you edge back south methinks

[Ali1977]

Control Also snowy on Tuesday 

[NewEra21]

Much prefer the UKMO compared to the gfs on this run.

Edited March 2, 2023 by NewEra21

[sheikhy]

I most certainly aint complaining bout the 12zs so far!!!ukmo is a big upgrade!!over to ecm to finish this off for us!!

[Kieran1960]

Just now, Ali1977 said:

Control Also snowy on Tuesday 

Not for the south though midlands northwards yes, but as I’ve been trying to highlight those along southern counties are likely to have a week of cold rain and sleet 

[Mark wheeler]

Just looking though the latest aprege run and it looks like the initial feature we were looking at for monday will be largely falling as rain , however there is some snow in the mix in places .
 

There afterwards the colder uppers start to arrive and there is a hint of showers approaching from the northern and east coasts . Obviously too far out at this juncture but thought I would share . 

[Ali1977]

3 minutes ago, Kieran1960 said:

Not for the south though midlands northwards yes, but as I’ve been trying to highlight those along southern counties are likely to have a week of cold rain and sleet 

Other frames are available 

[Mcconnor8]

4 minutes ago, Kieran1960 said:

Not for the south though midlands northwards yes, but as I’ve been trying to highlight those along southern counties are likely to have a week of cold rain and sleet 

I think the models may be underestimating how cold it will get under heavier precipitation, so think that we could end up with more turning from rain to snow than is suggested currently, at least hopefully

[nick sussex]

I’d advise those in the areas that could be effected by the Channel low to have low expectations. 

We’ve been here before many times and the thing can drive you nuts as the margin for error is low between rain , snow and a complete miss to the south.

 

 

[Lukesluckybunch]

UKMO 168 chart looks fantastic the cold air still in place and there would have been some snow around..my bet after this would be a return to a northerly,how long it lasts is another question!

[DIS1970]

May of posted this website before, plenty of interesting charts to keep you occupied during this major event awaiting to hit our shores - www.weathercharts.org.

[Drifter]

Day 7 UKMO  

[Mucka]

I still think the models are likely overplaying the Atlantics hand in the attempted breakdown on the 11th but we will see if that is reflected in the output over the next 48 hours.

The best day for snow chances before any breakdown attempt that could bring frontal snow will be the 7th as the Arctic trough digs SW.

GFS has low pressure developing over S of country as the bitter cold air from the NE meets milder Atlantic air coming up from the SW on the 7th.

UKMO has low embedded within the trough develop just to our E.

GFS is the snowier option and could give widespread snow whereas UKMO would pep up snow showers from the NE and drive them inland, 

UKMO/GFS 120h

 

The coldest temperatures will likely be on the 8th and 9th for any chance of local date records across England on those dates. A national minimum isn't likely and my original post alluded to potential date records for some locations in England. There are a lot of factors at play other than just cold air aloft here and it will require snow cover, clear skies and a col all of which may be in the forecast so we will wait and see.

Whatever happens the majority of people are likely to see snow falling at some stage before we welcome Spring so plenty to be excited about if you like that sort of thing.

 

 

Edited March 2, 2023 by Mucka

[Man With Beard]

11 minutes ago, nick sussex said:

I’d advise those in the areas that could be effected by the Channel low to have low expectations. 

We’ve been here before many times and the thing can drive you nuts as the margin for error is low between rain , snow and a complete miss to the south.

 

 

We've had so many unbelievably near misses in the past few years. Surely we're due a bullseye!

[Ali1977]

GEM on Tuesday 

[Tim Bland]

UKMO has got snow machine written all over it at t168..Shame we can’t see precip charts that far out ! 

[Mark wheeler]

17 minutes ago, nick sussex said:

I’d advise those in the areas that could be effected by the Channel low to have low expectations. 

We’ve been here before many times and the thing can drive you nuts as the margin for error is low between rain , snow and a complete miss to the south.

 

 

Agreed, normally edges south in time . However this has got me encouraged. Gem and Ukmo not too different. 

Edited March 2, 2023 by Mark wheeler

[nick sussex]

1 minute ago, Man With Beard said:

We've had so many unbelievably near misses in the past few years. Surely we're due a bullseye!

I’m saying nothing ! Channel Lows are the most difficult things to forecast and we’re both going to be made to suffer given our respective locations!