Model Output Discussion - Into Winter

[January Snowstorm]

Not much talk about the warmth predicted next weekend. Whatever happens at Christmas, the reliable timeframe is that it will turn exceptionally mild 

[LRD]

Hello darkness my old (winter) friend

[Bats32]

Just now, LRD said:

Hello darkness my old (winter) friend

Horrible,horrible,horrible.

[I remember Atlantic 252]

1 minute ago, January Snowstorm said:

Not much talk about the warmth predicted next weekend. Whatever happens at Christmas, the reliable timeframe is that it will turn exceptionally mild 

reckon a 20 is possible somewhere?

[LRD]

1 minute ago, January Snowstorm said:

Not much talk about the warmth predicted next weekend. Whatever happens at Christmas, the reliable timeframe is that it will turn exceptionally mild 

I know weather apps aren't up to much but I'm still seeing 7s and 8s for next weekend onwards. It'll be double that I reckon

[Cambrian]

If we look at the day 15 charts, for 0z Christmas Eve, from 0z EPS, 0z GEPS and 0z GEFS, the GEFS is the flattest, but going even flatter on the 6z run. And perhaps conspicuously so. 

The heights contours running through the north of Iceland are 522 dam for EPS, 528 dam for GEPS and 519 dam for GEFS on the 0z run, but down to 510 dam on the 6z. It’s also particularly progressive in building heights back in over Europe.

EPS, GEPS

  
 

GEFS 0z, 6z
 

The EC46 weekly anomalies I posted earlier (admittedly generated yesterday) are working off close to 525 dam for the north of Iceland for both the 18th-25th and 25th-1st. 

This might be the later GFS run picking up on an emerging signal based on newer data or it might be further over-developing the Iceland trough. Either way, the GFS at 0z was at the bottom end and at 6z it’s fair to say is rather out on its own, which is why I’ve been more focused on the northbound waves of amplification prior to that across all the models, where it looks like it’s all clearly all up for grabs for around day 8, let alone day 15, with a very wide range of outcomes possible.

[ANYWEATHER]

11 minutes ago, January Snowstorm said:

Not much talk about the warmth predicted next weekend. Whatever happens at Christmas, the reliable timeframe is that it will turn exceptionally mild 

I would say the reliable timeframe is not 8 days away thats in FI.

[January Snowstorm]

Here comes the Greenland high!! Next few frames could be good

[LRD]

1 minute ago, ANYWEATHER said:

I would say the reliable timeframe is not 8 days away thats in FI.

The trend towards that is obvious though. Exact details to be determined but an exceptionally warm spell from about the 16th or 17th is the front runner. The south might escape the worst of the warmth under an inversion but even that's doubtful

[TSNWK]

Here we go… umpth into Greenland or a flop over us…

[Nick F]

1 minute ago, LRD said:

The trend towards that is obvious though. Exact details to be determined but an exceptionally warm spell from about the 16th or 17th is the front runner. The south might escape the worst of the warmth under an inversion but even that's doubtful

I looked at the long draw SWly flow at 850 hPa, with T850s of 10C reaching the UK from the Azores around the 17th and all's not what it seems at the surface ...

Even the highs in the afternoon of 17th aren't screaming overly mild - more average.

All an educated guess that far off though ...

 

[Dennis]

the turnaround

 

[LRD]

1 minute ago, Nick F said:

I looked at the long draw SWly flow at 850 hPa, with T850s of 10C reaching the UK from the Azores around the 17th and all's not what it seems at the surface ...

Even the highs in the afternoon of 17th aren't screaming overly mild - more average.

All an educated guess that far off though ...

 

Thanks Nick. That's really strange. SW wind, high uppers and only producing those temps.

[January Snowstorm]

That 246 chart, which is obviously deep FI, has plenty of potential!! Opens up all sorts of possibilities as we into Christmas 

Edited December 9, 2023 by January Snowstorm

[TSNWK]

5 minutes ago, TSNWK said:

Here we go… umpth into Greenland or a flop over us…

Looks like a short blast on this run.. not enough into Greenland..

[That ECM]

Consistent. Right or wrong tho?

[LRD]

Another unconvincing attempt by the high pressure system to reach Greenland

But I'm sure the ridging to Greenland is continually being brought forward in time. So that's something

[joggs]

1 minute ago, That ECM said:

Consistent. Right or wrong tho?

If the background sigs are correct. On the money imo.

[Nick F]

Just now, LRD said:

Thanks Nick. That's really strange. SW wind, high uppers and only producing those temps.

Quite an inversion going on, especially in the south. Clear skies at night lead to temperatures dropping like a stone near the longest night of the year if the air is dry, which it would be under a strong upper level ridge with dry air subsiding from high up - which also evaporates any cloud.

[LRD]

5 minutes ago, Nick F said:

Quite an inversion going on, especially in the south. Clear skies at night lead to temperatures dropping like a stone near the longest night of the year if the air is dry, which it would be under a strong upper level ridge with dry air subsiding from high up - which also evaporates any cloud.

Thanks again. That's a helpful explanation

 

Edited December 9, 2023 by LRD

[Gowon]

The GEM is still more amplified to our NE than the GFS.

 

[Dennis]

late dec23 

Edited December 9, 2023 by Dennis

[Nick F]

Just now, Dennis said:

late dec23 will show cold days 

Always the optimist!

The trop PV is not one for splitting to allow height rises over Greenland on recent GFS runs, maybe a new trend that won't reverse and get worse just before Xmas, or it may revert back to decent splitting into separate vortices over N Canada and NE Europe like the more colder runs of previous days. More runs needed.

12z GFS does at least drag down some cold arctic air, but with the TPV not splitting to allow the Atlantic ridge to build north over Greenland, any cold incursion would be prone to being toppled from the NW by mild sectors.

[LRD]

Well, it's not Narnia in FI but it certainly ain't mild either. That High is toppling in though. Mild by Boxing Day I'd have thought (if that pans out like that of course)

But, let's face it, hopes of a proper cold spell over Xmas are fading fast. It's been a poor day for those prospects really

Edited December 9, 2023 by LRD

[Dennis]

4 minutes ago, Nick F said:

Always the optimist!

but with the TPV not splitting to allow the Atlantic ridge to build north over Greenland, any cold incursion would be prone to being toppled from the NW by mild sectors.

Get in the train 

the TPV could be split (seen on some other charts allready )

2 times .....chanche gfs12 (just before the Xmas days)