Model output discussion - late November

[IDO]

JFF FI shows the euro trough still showing, just less of a wedge like scenario due to earlier changes:

06z>  0z> 

Not a bad setup as we head towards mid/late December.

[Methuselah]

Another run, another 'trend':

I'll take it!!!

[StretfordEnd1996]

GFS from D8 onwards until the end of the run isn't perhaps as cold compared to recent runs but nonetheless it still shows ridging trying to get going to the W/NW at various stages (and yes before D10)

Doesn't quite stay there but it's nice to see it still being shown rather than a total lack of heights

 

Prior to all this in the nearer time frame, scarves and hats are required thanks to some lovely cold tingling charts

 

Edited November 29, 2019 by StretfordEnd1996

[Ali1977]

an upside down teddy bear in FI, very cold if it carried on 

[Guest]

29 minutes ago, IDO said:

JFF FI shows the euro trough still showing, just less of a wedge like scenario due to earlier changes:

06z>  0z> 

Not a bad setup as we head towards mid/late December.

Thats an election wrecker  

[Methuselah]

So here we are, at T+384, with what looks like a favourable synoptic-pattern for us here in Blighty. But, not only does it rely on the Azores High being sucked well away westwards, it's strikingly similar to some of the more far-fetched scenarios 'on offer' this time, last year? Should I sell-up and move to Fantasy Island once-and-for-all!

   

PS: No squirrels were harmed during the making of this post!

[Chesil View]

Forgetting the Intra run variations for a moment and looking at  the general trend on the op runs. The extended range GFS is working very hard to bring us cold from anywhere from NW through to NE by dropping pressure over Scandi and Northwest Russia courtesy of the polar vortex moving into Siberia

[tight isobar]

Watch for the dropline increase on the 6z ensembles..

As mentioned-the Siberian sector pv increase..Will surely be of note...

And the ensemble/supports...Will highly likely begin to look stark...in member belly dropping...let's see!!!

[tight isobar]

And...

The notion is there...mixed...but the scatter/compaction..

Certainly going in the wanted direction.

Edited November 29, 2019 by tight isobar

[StretfordEnd1996]

A bit more of an ensemble trend emerging now for around D8-10 with uppers dipping cold again - the mean dips very close to -5 uppers for this time frame (with the op actually an milder outlier for this specific time frame too)

Majority of the colder members will be down to a colder NW'ly or N'ly incursion (and not anything more potent than that)

Most members then warm up a tad whilst the op then takes over the reins of introducing some more organised cold..

Interesting times

[Ninman]

P18 will do..

From a developing ridge

.

To a wedge with undercut...nice!

Chefs are starting to bring their dishes to the table for Christmas dinner..could be a good feast on the menu!

[Methuselah]

'Tis good to see that the GFS 06Z operational run is not an outlier; and, considering the latest indications regarding the expected location of the TPV, it might actually be on to something. Then again, it might not! Only time will tell...?

   

   

And, perhaps more importantly, the outlook looks mostly dry!

[knocker]

This morning's ext EPS is similar to last evening's so no need for me to waffle too much

Essentially the main vortex lobe northern Canada with two outliers with the key one regarding the UK the trough down Scandinavia into Europe and how far south it stretches is quite important. The reason being the ridge into eastern Greenland that has been established, splits the westerly flow and how far south the northern arm, and the cold air can reach, rather depends on the trough.

And a further quick word on this morning's kerfuffle about 850mb and surface temps with an Autumn anticyclone. It's about our old friends divergence and convergence and with the former occurring in the lower regions and the latter at the top air within the anticyclone subsides and warms adiabatically, and this time of year the warmer and drier air will often suppress cloud formation so you don't get a Sc layer but if sitting on cold air already in situ, which is not subject to mixing, the lapse rate in the lower layers is severely compromised and it will remain cold

 

Edited November 29, 2019 by knocker

[Frosty.]

Looking at the GEFS 6z mean there's very  good support for a polar / arctic maritime blast in just over a week from now and probably that potential continues at times further ahead..could turn into an exciting month ahead...if you love cold and snow!!!

 

Edited November 29, 2019 by JON SNOW

[Anthony Burden]

Could be some time before double figures are reached in the south of England a cold spell that’s for sure.

looking ahead temperatures will more likely be below average rather than above.Winter starting very good

for cold lovers.

[SMU]

17 minutes ago, Anthony Burden said:

Could be some time before double figures are reached in the south of England a cold spell that’s for sure.

looking ahead temperatures will more likely be below average rather than above.Winter starting very good

for cold lovers.

Yes 

( & afternoon All )

The cold spell is certainly longer than initially expected so while the 850s lift it stays cold > especially in the CET zone so a sub 3c first week of December is on the cards !

Realistically the mild temps only arrive for 2 days before being chased down again from the North once more-

It looks like another chase on the cards for a wedge - maybe slightly higher chance of it happening this time as the zonal wind decreases & the high pressure ridge hopefully takes on a more vertical alignment -

[Mair Snaw]

Some fantastic looking output over the last few days and while we all know the chances of it happening are slim but you never know. 

[Jordan S]

I've seen from early next year, the GFS ensembles will go right out to T+840,  35 days ahead.. if over 240hr is fi then what shall we call that timeframe? "outer space" ?

Back to the uk a cold and frosty few days in store with the cold lingering until atleast midweek next week where Atlantic disturbances may begin to effect the north the three main models have a decent handle for 6 days away.. But a little ahead and the Ecmwf diverges somewhat as you would expect in semi unreliable timeframe. 

GFS..

Gem..

Ecmwf..

Here's a snapshot for day 10 from the three models... 

GFS..

Gem..

Ecmwf..

GFS a blend really between the Gem and Ecmwf with a chilly but unsettled northwesterly airflow with spells of rain at times. 

Gem very wet for England and Wales showery for the north chilly too but milder further south. 

Ecmwf shows high pressure to the west allowing a northerly wind to effect the uk this cold too with wintry areas of precipitation for the east but a mostly dry picture. 

Remember I'm simply describing what the models are showing for that time it's just a snapshot and liable to change.

Edited November 29, 2019 by jordan smith

[Methuselah]

Well, back here on Planet Earth, December looks like getting off to a decidedly (faux) cold start; ice-days likely anywhere fog persists...So, a stonking start for those whose CET predictions are low...?

   

[Methuselah]

Still looking good @T+252...Plenty of cold air for us to tap into...?

   

Come on, now...come to Daddy...? Thatta good boy!

   

 

Edited November 29, 2019 by Ed Stone

[That ECM]

8 minutes ago, Ed Stone said:

Still looking good @T+252...Plenty of cold air for us to tap into...?

   

Another interesting and intriguing run from gfs, with some very cold air not to far ne. 

Edited November 29, 2019 by That ECM

[SMU]

Yes this type of chart whilst not exhibiting extreme Northern blocking is about as primed for snow in the UK as your ever going to get!

[IDO]

Pleasing charts and only 19,440 minutes away:

`

We get the hi-lat wedge on this run redirecting the cold UK bound.

JFF but lots of potential.

[That ECM]

8 minutes ago, Steve Murr said:

Yes this type of chart whilst not exhibiting extreme Northern blocking is about as primed for snow in the UK as your ever going to get!

Like that you mean let’s count it down

[SLEETY]

pretty impressive blizzard raging over Dartmoor on this run at 3000 minutes or whatever it is 

Imagine if  that sort of chart ever got to within 72hours lol

Edited November 29, 2019 by SLEETY