Model output discussion 24/01/21

[Griff]

Past my bed time, here's latest parallel at 150 looks consistent too

[Cavehill Snow]

21 minutes ago, nick sussex said:

I’m sure they built the Pyramids quicker ! Jeez this is like watching paint dry . I’ve seen countless easterly evolutions over the years and this one takes the Gold Medal for dragging out the drama to get there !

I think because we get the 6 hour steps it does make it seem longer . When the GFS blew up those two shortwaves over the UK I thought here we go ! This is going to be painful ! 

We are only about half way through the journey to reach the potentially really deep cold next weekend. Not sure i've got the stamina to watch the runs 4 times each day until then.

[Tim Bland]

Prefer the 12z that annoying ‘phasing again’ causing the clear differences below..

[Allseasons-Si]

The parra setting up shop here at 144...

but my time has come to a close,work permitting tomorrow a 6am

here is the latest from the gfs op...,i will dream of Narnia tonight,goodnight.

 

[ICE COLD]

27 minutes ago, ICE COLD said:

I reckon we could get the -15 line in

We didn’t quite get the -15 line in but -13 will do

[Griff]

1 minute ago, Tim Bland said:

Prefer the 12z that annoying ‘phasing again’ causing the clear differences below..

Good thing none of these evolutions will ever repeat come the next run then!

[Mark wheeler]

31 minutes ago, Chertseystreamer79 said:

Are yellow hatching's sleet? Tia...

Yep  

[Chiltern_Blizzard]

47 minutes ago, Tim Bland said:

Different posters like to discuss different things. For example some post the clusters, some the ensembles and some like to post 384hr FI charts. Personally I prefer to discuss snow fall and it’s location when it’s within a few days. There is an ignore function which can use to tailor your experience on here, so if you don’t want to see posts about snow fall and charts discussing it then please hit ignore on me .

Back on topic and here is the 18z Harmonie model, probably best of the bunch this evening for widespread snow. Arpege has plenty of precip but is mainly rain or sleet ...

I'm with you! Arperge wasn't the best last weekend from memory. Kept  snow at the m4 line...when in actually went much further north. Hoping harmonie has it correct again

[joggs]

Most models and signs point cold. A very different from the norm.  

Goodnight all. Here's to the 6z letting us coldies down..........

[Nick F]

Only 7 days away from the magic -10C T850 line hitting Scotland on 18z GFS, 8-9 days further south as the easterly develops further south. Pressure and heights look low over the North Sea too, so with that depth of cold the sea will be a snow shower machine.

What could go wrong? Maybe the 00z runs will show what could. Need EC op on board. Joking aside, consistency from the GFS operationals today and ensemble means is giving increasing confidence today this may happen ...

Edited January 28, 2021 by Nick F

[SLEETY]

Torture getting deep cold Easterlies into UK lol. Probably not until next weds till we can be much more certain, so around 24 more gfs runs, what could go wrong... 

[Matt H]

The GEFS 18z ensemble mean at t228 is brilliant. The easterly is definitely gaining momentum still!

[Uncertainty]

3 minutes ago, Nick F said:

Only 7 days away from the magic -10C T850 line hitting Scotland on 18z GFS, 8-9 days further south as the easterly develops further south. Pressure and heights look low over the North Sea too, so with that depth of cold it the sea will be a snow shower machine.

What could go wrong? Maybe the 00z runs will show what could. Need EC op on board. Joking aside, consitency from the GFS operationals today and ensemble means is giving increasing confidence today this may happen ...

Yes Nick other than the EC op if the means stay rock solid for 6-8 more runs then we’re just about there.

GFS p showing the worst case scenario, could see UKMO heading that way with minimal Atlantic ridging so this isn’t quite  done yet. Ec op And JMA op not also not ideal so until we get everyone aboard a waiting game it remains (albeit a really exciting one!)

[Man With Beard]

What we've seen today is we're not getting a standard Scandi High - we're getting an exploded PV with fragments going all over the place. It would be a mistake to think it will be 2018 all over again. It might be, but it all seems a bit random right now. Need more runs!

[TEITS]

I haven't much time but I thought I would make a few points.

1. Unconvinced of snow risk this weekend. The area condusive to see snow rather than rain will see little or no precip at all in my opinion. Im thinking my location, midlands etc. Snowfalls mainly reserved for higher ground in Wales, possibly SW England. A shift S is likely to continue with this low.

2. The milder spell next week is more likely to become shorter. The 18Z GFS has the low at+144 way too far N as its underestimating the forcing from the blocking to the N. The result being a faster E,ly setting in than currently modelled.

3. Some of these runs have been mindblowing i.e -17C upper temps. I am not sure I wish to see such an extreme cold spell. This will delay vaccinations and probably extend lockdown!

[Man With Beard]

18 minutes ago, TEITS said:

 

20 minutes ago, TEITS said:

I haven't much time but I thought I would make a few points.

1. Unconvinced of snow risk this weekend. The area condusive to see snow rather than rain will see little or no precip at all in my opinion. Im thinking my location, midlands etc. Snowfalls mainly reserved for higher ground in Wales, possibly SW England. A shift S is likely to continue with this low.

2. The milder spell next week is more likely to become shorter. The 18Z GFS has the low at+144 way too far N as its underestimating the forcing from the blocking to the N. The result being a faster E,ly setting in than currently modelled.

3. Some of these runs have been mindblowing i.e -17C upper temps. I am not sure I wish to see such an extreme cold spell. This will delay vaccinations and probably extend lockdown!

 

Point 1 and 2 = agreed. Models are unsure what will happen this weekend, and that usually means unlikely to be a notable snow event now, though still a possibility. With T144, I agree that models tend to be a bit behind in the direction of the flow, which would suggest an even quicker transition than currently signalled.

Point 3 though - if I'm allowed to say, a decent snowfall may be more effective in keeping people away from Tesco's and shutting the schools than the lockdown rules, maybe?

[SLEETY]

What minus 17 upper air at surfscev

31 minutes ago, TEITS said:

I haven't much time but I thought I would make a few points.

1. Unconvinced of snow risk this weekend. The area condusive to see snow rather than rain will see little or no precip at all in my opinion. Im thinking my location, midlands etc. Snowfalls mainly reserved for higher ground in Wales, possibly SW England. A shift S is likely to continue with this low.

2. The milder spell next week is more likely to become shorter. The 18Z GFS has the low at+144 way too far N as its underestimating the forcing from the blocking to the N. The result being a faster E,ly setting in than currently modelled.

3. Some of these runs have been mindblowing i.e -17C upper temps. I am not sure I wish to see such an extreme cold spell. This will delay vaccinations and probably extend lockdown!

WHats minus 17c at surface level, I'm guessing around minus 3 daytime maxes, quite extreme for UK, probably have contingency plans if it does happen, like 4x4 vehicles, etc, met won't make much fuss about it yet, until, if it gets into semi_reliable timeframe.

Helsinki ensembles are even more extreme,some are  getting towards minus 25 upper air!! important because that's the source of where our air will be coming from if all this verifys. 

Edited January 29, 2021 by SLEETY

[starstream]

I recall during 2009 or

maybe 2010 a plea

going out for anyone with 4x4 vehicles to help support various services ( district nurses and ambulance crews being etc) if and I appreciate it’s an if, the hoped for cold

spell does turn out to be a beastie then surely  under the present situation they couldn’t request such support from the general population?

all academic at this range,

no hopes being raised in the house to T-72!

[Wardlegacy]

2 hours ago, starstream said:

I recall during 2009 or

maybe 2010 a plea

going out for anyone with 4x4 vehicles to help support various services ( district nurses and ambulance crews being etc) if and I appreciate it’s an if, the hoped for cold

spell does turn out to be a beastie then surely  under the present situation they couldn’t request such support from the general population?

all academic at this range,

no hopes being raised in the house to T-72!

There are dedicated 4x4 owner organisations covering the whole country ready to be used who have already been busy this year.

[northwestsnow]

ICON 144.

Just follow the damn thing GFS/UKMO/EC!!

Edit 168...

Edited January 29, 2021 by northwestsnow

[Daniel*]

Can we just take a moment to appreciate how crazy this hemispheric picture is, the SSW / secondary warning has truly done its magic here. Very exciting. 

[Battleground Snow]

Ukmo at 144.

I think it's good and the low would eventually clear south East and open the door from the east.

 

[northwestsnow]

UKMO

[Battleground Snow]

Just now, northwestsnow said:

UKMO

I'm happy if NWS is happy.

Beast arrives in a week according to the GHS OP

[Kentspur]

Lovely Icon 0z -10c uppers hovering around the SE  4th- 5th Feb and a good easterly draw