Model output discussion - Winter approaches

[sebastiaan1973]

What a big difference between UKMO and GFS at 144H. Incredible.

Edited November 22, 2020 by sebastiaan1973

[Frosty.]

Just looked at the GEFS 6z..(already obsolete probably)?...but later in the week ahead would become more widely settled for a time?..longer term I’m seeing either a N/S...NW/SE split with heights to the south meaning southern u k is generally less unsettled compared to the N / NW?...hoping for a wintry signal but not really seeing any support for it at the moment..I think that’s a fair assessment of the GEFS 6z?..notice my lack of confidence in what I’m saying means I have to include a ??

 

Edited November 22, 2020 by Jon Snow

[SMU]

Surprise snow for the North Day 8

[Cheshire Freeze]

GFS looks at tad more amplified, to me, at day 8 than even the 6z

[mb018538]

6 minutes ago, Steve Murr said:

Very seasonal 12z GFS with low Theta E temps for NW Europe & dead stationary air!

Dead stationary air, and the customary @Steve Murr dead battery!

[nick sussex]

The UKMO is an improvement in terms of the alignment of the blocking to the east compared to this mornings run. It’s by no means great but moving in the right direction .

The GFS seems quite messy later on but not bad with that slack flow for a time which could provide an inversion type scenario .

The troughing to the nw now looks likely given the model agreement to run out of steam but how much energy disrupts se wards still quite uncertain .

Overall not a bad start to tonights outputs in terms of potential but we’re still missing a clear route to advect some colder upper air in from the east or ne . 

The much debated faux cold looks in evidence for the time being.

Still it could be worse . Let’s hope the ECM can up the ante .

[Zak M]

The GFS parallel is hinting at something a bit different ...

   

[SMU]

Hum - More &more ENS with just a smidge higher pressure over Scandi at 126 leaves this type of flow...

[Eskimo]

3 minutes ago, Steve Murr said:

Hum - More &more ENS with just a smidge higher pressure over Scandi at 126 leaves this type of flow...

[Ols500]

Could someone explain Theta-e temps?

850s are easy to underatand, (-10 very cold, +10 very mild etc)

what temperature for theta-e is cold? 

Thanks.

[SMU]

1 minute ago, Ols500 said:

Could someone explain Theta-e temps?

850s are easy to underatand, (-10 very cold, +10 very mild etc)

what temperature for theta-e is cold? 

Thanks.

Sub 8c really for snow. Anything below 12c in November is cold.

Its a good chart to identify the airmass as well

Edited November 22, 2020 by Steve Murr

[Ols500]

1 minute ago, Steve Murr said:

Sub 8c really for snow. Anything below 12c in November is cold.

Its a good chart to identify the airmass as well

Thanks. I'm gonna read up on it

[Cheshire Freeze]

Look at the body blow being inflicted on the vortex-

All good if we can get anywhere near this point...

[IDO]

That core Russian/Euro high is a pain, a conduit, a run-off for the Azores scrapes that feed through the lower Iberian heights:

gfs d11 >> 

Its westerly flank, too close, preventing the Atlantic from sending lower heights to reinforce the Iberian low. Our region is primed for some HLB if we can get the forcing in before the pattern changes. Unfortunately the whole NH is benign with the Pacific high unwilling to ridge.

From a viewing perspective it is very interesting as a more meridional flow within the next 16-days could be promising if the cards fall right? ATM a bit of a waste of a great synoptic.

[Anthony Burden]

A definite battle going on with Atlantic v continental air for most of U.K.

gfs 12z stays with continental holding firm.Temperatures to remain in single figures 

possibly turning chilly.

[Cheshire Freeze]

15 minutes ago, IDO said:

That core Russian/Euro high is a pain,

Far from it. These heights are keeping us in the long game. They will do much more for us than Greenland heights which would let the strat and trop couple more effectively during December. 

If you look at the strat charts, you can see that the SPV may be taken out through the back door eventually as there appears to be a signal for a bottom-up warming due to constant Russian heights and Aleutian LP. This would stand us in good stead from Jan onwards.

You can see the warmth starting to circle at 30HPA

Edited November 22, 2020 by CreweCold

[dragan]

lows to the west, high to the east means we are sucking up air from the south, although not overly mild, it will keep temps around average (this is later frames of gfs)

[Eskimo]

Yes, it isn't a screaming easterly with frequent heavy snow showers - this chart is beautiful for a seasonal spell of weather with very chilly temperatures and frost lingering all day. 


 

[IDO]

2 minutes ago, CreweCold said:

Far from it. These heights are keeping us in the long game. They will do much more for us than Greenland heights which would let the strat and trop couple more effectively during December. 

If you look at the strat charts, you can see that the SPV may be taken out through the back door eventually as there appears to be a signal for a bottom-up warming due to constant Russian heights and Aleutian LP. This would stand us in good stead from Jan onwards.

I have given up a bit on that strat-trop coupling after last year(s), but yes, a possibility!

The latter stages of FI and FWIW (poss not a lot) a nice wedge of heights over NE Canada; could change things up...

...if only to put a temporary stall on the HP train of Pacific>Azores>Euro/Russia!

[SMU]

Looking at the tail end of the GFS v the 168 cold pool you can see how much better it is as we hit December ( second chart )

[Anthony Burden]

UKMO showing strong Scandinavian high 130mb/135mb at 144hrs with east /south east flow

over U.K. Orientation of high will determine the temperatures,along with length of time it remains.

[Tim Bland]

GEM looks good at the end..wish it went a few days further. Certainly lots of possibilities for cold as we head towards December ...

[SMU]

ECM 120 very chilly surface flow out of the East

Odd wintry flurry possible over the york moors (-5c uppers)

Edited November 22, 2020 by Steve Murr

[northwestsnow]

Looking at EC temps should drop away wed onwards ...

Certainly ideal Christmas markets weather....

Typical...

[Tim Bland]

Boom