Model output discussion - deep cold inbound?

[Weather of Mass Disruption]

4 hours ago, Ali1977 said:

I’m sure these figures are underplaying the shower activity off the North sea, but pretty widespread snow, and deep in many places.

I feel we have a stinking ECM about to rope out!! 

I know these charts are no to be taken too seriously, but that said, if we have cold easterly winds across most of the country with precipitation moving up from the South West how does Cornwall and Devon stay clear of any snow. Seems implausible to me, unless there is some warmth mixed in with it? 

[ITSY]

9 minutes ago, MattStoke said:

ICON pushes fronts further north over the weekend. Raining turn to snow as it crosses England and Wales, Saturday night through Sunday. Marginal for south eastern areas (At that stage).

It pushes the showery activity north throughout Saturday but keeps the frontal system on Sunday for coastal counties only, pushing the snow further south and east towards Suffolk only for significant falls (over a few cams). One to watch as from an imby POV the 00z icon was much better for the weekend. Let’s see what gfs brings - looks good for the moment, and very different too!

Edited February 4, 2021 by ITSY

[If Wishes made Weather]

41 minutes ago, Tim Bland said:

And it’s 3c above the mean at the end for the south!!!

... and by virtue of that is (I think disproportionally owing to its weighting) dragging the mean up anyway.

[Notty]

GFS 06z Op making a bit more of the snow on Sunday for the South/East

[kold weather]

8 minutes ago, bluearmy said:

I think that’s pretty disingenuous. Gfs was the model that sniffed the Iberian low pushing quickly northeast to engage our sinking low over the Low Countries. It just made a mess of that interaction and had it a little too far west.  The experience watchers on here dismissed the mess it was making of the meeting of the two air masses but were cautious about ignoring it completely. and they were right to do that. 

Yeah I think I spent most of Sunday telling people to be aware that the GFS was a real risk.

As it happened, the GFS did what it normally does and went into turbo mode with overdeveloping a low pressure too quickly but the end result despite of this wasnt too far removed from what we are seeing.

 

[radiohead]

Colder air pushing slightly further westwards on the 06Z GFS.

[kold weather]

7 minutes ago, ITSY said:

It pushes the showery activity north throughout Saturday but keeps the frontal system on Sunday for coastal counties only, pushing the snow further south and east towards Suffolk only for significant falls (over a few cams). One to watch as from an imby POV the 00z icon was much better for the weekend. Let’s see what gfs brings - looks good for the moment, and very different too!

A heck of alot of showers coming through on the ICON though on Monday in particular which probably would make up a certain amount of the difference.

To have any decent sort of convective return showing on the ICON suggests a very impressive signal at this range. The ICON really struggles with winter time overland convection.

ICON is a little further east that is true on its 06z run, though the frontal precip shield still extends from the Wash down to the IoW.

[Battleground Snow]

Icon by Tuesday morning, looks healthy for most 

 

[ITSY]

3 minutes ago, Notty said:

GFS 06z Op making a bit more of the snow on Sunday for the South/East

It does indeed! It reinvigorates the front and keeps it stalled over all the east of england, with snow falling from +66 to +90 hours. Just like the 00z! Widespread 10-15cms in that event...

[NewEra21]

9 minutes ago, ITSY said:

It pushes the showery activity north throughout Saturday but keeps the frontal system on Sunday for coastal counties only, pushing the snow further south and east towards Suffolk only for significant falls (over a few cams). One to watch as from an imby POV the 00z icon was much better for the weekend. Let’s see what gfs brings - looks good for the moment, and very different too!

Doesn't look too bad for Sunday?

[DAVE_ALLEN]

2 minutes ago, ITSY said:

It does indeed! It reinvigorates the front and keeps it stalled over all the east of england, with snow falling from +66 to +90 hours. Just like the 00z! Widespread 10-15cms in that event...

I can see a few MO Red Warnings being issued for London & SE within 24 hours if that GFS 6z comes off

[That ECM]

Still seeing the trend.  Met have dropped Bournemouth 2 degrees for mon Tuesday wed. 2 max now.

Edited February 4, 2021 by That ECM

[Matt H]

GFS 06z looks like another upgrade to me out to t102 with -12C uppers pushing further west combined with stronger heights to our north which may help to prolong the cold spell on this run as well.

 

 

Edited February 4, 2021 by Frosty Winter

[radiohead]

06Z at just 102 hours. -10 uppers spilling further westward and -12 has reached the east already. Upgrade on the 0Z.

 

[SqueakheartLW]

My latest model update and after looking through them before giving this update I am liking what I see

GFS 18z

Normally I would just give a brief summary here and quickly get onto the 00z but after what I saw I can't help but give a proper update for the 18z too. The peak of the cold spell on this run came at 114 hours away so still getting closer at least.

Now if that isn't a decent looking beasterly average showing at 114 hours away then what could an improvement look like to this. The 00z is going to have a lot to live up to after that pressure chart. The 850hpa temperature also reflects this with a new low of -10.7 which is -7.4 below the long term mean and breaks the record set by the 00z on Mon 1st Feb by -0.3. A nice little upgrade here and back where I feel we should belong in the sub -10 region. The anomaly chart is also the coldest I have seen so far with deep blues nationwide and even a patch of pink close to us now. Any more upgrades and we may even see some of those pinks over the UK.

GFS 00z

After the record setting 18z this 00z has a lot to live up to but can it be even colder or will it still be a decent run at least. The peak of the cold spell on this run came at 102 hours away so has crept even closer since the 18z

The best part about this was the maintaining of the decent looking beasterly pressure chart signal. The 850hpa temperatures for the 00z were a slight downgrade to -10.2 which is still -7.6 below the long term mean but a 0.5 downgrade on the 18z which is the bad point about the 00z but at least it was still the 3rd coldest update for the GFS so far and was still below the -10 region. The anomaly chart also looks less cold too and that pink patch has also gone. Hope the 06z can be another sub -10 run again.

GEM 00z

The GEM has in general been more on board with the colder spell throughout and with several decent runs recently this 00z has something to live up to. The peak of the colder spell on this run is at 138 hours away. The good news is that GEM is still on board and has only gone and set a new coldest run so far of -10.0 at the peak of the cold spell which is -6.6 below the long term mean and breaks the previous coldest by -0.3 which was in fact the previous 12z run. With general upgrades by both GFS and GEM then the GFS Extended better also be on board with an upgrade too.

GFS Extended

After some decent upgrades by both GFS and GEM and after such a poor showing yesterday the GFS Extended really needs to rescue itself before I consider it a run for the bin. The peak of the colder spell on today's extended run is at 132 hours away

An average easterly still showing on the GFS Extended so that is still on track at least. The 850hpa temperature is also a step back in the right direction at -8.5 which is -5.2 below the long term mean and an upgrade of -2.0 from yesterday so the GFS Extended can be saved for a day at least. The anomaly chart also reflects this -2.0 upgrade with the blues getting deeper over the UK again.

[kold weather]

06z GFS just edges the low further north again and is closer to yesterday mornings runs with a little milder air coming back into the far southern coastal counties in the SE again, however the surface flow is really cold by this point which makes the slightly milder 850hpa temperatures less important.

Sunday is a very snowy looking day with pretty constant light/moderate snow coming in across much of the south of England.

Based on the ensembles though and other OPs, the GFS is a little too far NW.

 

[Don]

4 minutes ago, Battleground Snow said:

Icon by Tuesday morning, looks healthy for most 

 

It does indeed but looks a little poor for my location.  However, still a long way out and I’m sure most parts of the country will get their fair share at some point in the next week!

[Don]

3 minutes ago, DAVE_ALLEN said:

I can see a few MO Red Warnings being issued for London & SE within 24 hours if that GFS 6z comes off

Feb 2009 repeat?

[sheikhy]

Nothing much to add!!the 06z take up a notch again!!we as snow lovers dream about these kinda charts!!very very rare indeed!!!only down side is it looks like i wont be able to run for a period of time from saturday evening!!!also with a rear wheel drive car gona be stuck at home quite literally!!but its all for snow so i will take it❄

[ITSY]

4 minutes ago, NewEra21 said:

Doesn't look too bad for Sunday?

It’s subtle changes with big impacts. Leicestershire, Lincolnshire, Cambridgeshire, Bedfordshire etc would all get a a dusting from the icon. Whereas on the 06z GFS many of them have 10-15cms by Monday with snowfall from +66 to *checks notes* +108! See below. Way too early to be bogged down in details but needs watching for some of us - for others, like those in southern Norfolk or Suffolk, it looks tidy all round! 
 

[kold weather]

Very snowy run so far on the 06z GFS it has to be said, snowfall getting far further west than most other models from this morning.

Would be good to see it come off as the GFS brings further west locations into play west of the IoW, where as all other models keep it broadly limited to the east of IoW, and any significant snow much further east.

Sunday will probably come down to the radar, we've already seen several times where the models have not done a great job at precip distribution even at 12hrs out.

Edited February 4, 2021 by kold weather

[DAVE_ALLEN]

Notice the dry area where the upper level cirrus/stratus spreads out from the frontal snow further south east. This cloud shield often prevents the development of showery activitiy 

[Ice Day]

This GFS run is absolutely unbelievable.  Very cold for all and very snowy for some.  At 114 hrs

  

Monday is looking a snowy day for many areas

 

 

 

[I remember Atlantic 252]

1 minute ago, DAVE_ALLEN said:

Notice the dry area where the upper level cirrus/stratus spreads out from the frontal snow further south east. This cloud shield often prevents the development of showery activitiy 

Agree with this, my thoughts exactly, long way off still but on this 06Z, I expect very little snow here on Sunday

[ALL ABOARD]

Locked in. 

No way the Atlantic lows barrel in now.