Model output discussion - Winter approaches

[bluearmy]

The output has been strikingly poor for continuity - the fact we  main op models roughly on the same page days 7-9 is v Interesting . 
 

the eps clusters have gone from 2 this morning to 4 this evening - big variations so best to remain cautious and see fi we can regain the op continuity on the 00z - if we do then the ens may begin to follow more convincingly 

[damianslaw]

Unusual synoptical evolution being shown by both GFS and ECM, even more unusual given they are both in sync.. something is stirring...

As others have said its the broad scale northern hemispheric pattern that is eye raising, the PV as shown yesterday being shown to move to the Asian side, enabling heights to develop over N Canada and more importantly into Greenland, end result is a highly amplified flow, with a large cut off low/trough feature anchoring itself to our south and south west, with a ridge to the north. When you see such a development its an indication a major shake up is being forecast. 

The theme for the foreseeable is a fairly settled one rather than unsettled, near timeframe some welcome sunshine hopefully though could be quite cloudy, fog and frost, under low cloud and fog it will be cold with little wind to stir things, surface cold will build quickly.  Into next week signs we may see something a bit more unsettled and milder, thereafter, who knows.. something substantively colder from a northerly flow, or nearer average with some rain in the south.. its all very uncertain though.

[nick sussex]

The ECM and GFS seem to be converging on an interesting but not outlandish evolution with troughing near the UK disrupting s/se with pressure trying to build to the nw .

If the PV does actually relocate east ne in its entirety then you’d be very unlucky to not see some interest for coldies .

What would be nice beforehand is to get more energy heading se rather than south as that troughing disrupts .

For two reasons ,that could help advect some colder air into the UK from any cold pool further east/se and secondly low pressure in the northern Med rather than Iberia would act as a good foundation to support any high which develops to the nw .

 

Edited November 24, 2020 by nick sussex

[Tom Jarvis]

25 minutes ago, nick sussex said:

The ECM and GFS seem to be converging on an interesting but not outlandish evolution with troughing near the UK disrupting s/se with pressure trying to build to the nw .

If the PV does actually relocate east ne in its entirety then you’d be very unlucky to not see some interest for coldies .

What would be nice beforehand is to get more energy heading se rather than south as that troughing disrupts .

For two reasons ,that could help advect some colder air into the UK from any cold pool further east/se and secondly low pressure in the northern Med rather than Iberia would act as a good foundation to support any high which develops to the nw .

 

Fingers crossed Nick. The last few years have been v poor even when there were some good background signal. Can I ask what drives the PV to locate in that area rather than the dreaded Greenland limpet location it has been for the last few years. 

[bluearmy]

8 minutes ago, Tom Jarvis said:

Fingers crossed Nick. The last few years have been v poor even when there were some good background signal. Can I ask what drives the PV to locate in that area rather than the dreaded Greenland limpet location it has been for the last few years. 

Social distancing from the USA .....

[sheikhy]

Very continental 18z gfs so far!!scandi high upgraded again!!gona feel a lot colder from tomorrow night i think!!

[Eskimo]

Quite a difference already at +150h. Cold pool nudging into the UK. 

12z                                                               18z

.

Edited November 24, 2020 by PerfectStorm

[Eskimo]

 

[That ECM]

3 minutes ago, PerfectStorm said:

Quite a difference already at +150h. Cold pool nudging into the UK. 

12z                                                               18z

.

Good continuity overall in terms of the nh profile. Great model viewing, hopefully this will lead to even better lamppost watching.

[fellmike]

2 hours ago, CreweCold said:

The evolution over the past couple of weeks has been excellent. It has built and built in terms of potential, and this has accelerated over the past few days. Even in isolation, the synoptic evolution over the next few days is good- solid for building what we are now seeing at days 9&10.

Whether we see a N'ly shown at days 9&10 that affects the UK is, at this point, moot. The hemispheric set up is absolutely ripe to deliver the UK a cold spell into December- I saw how it was shaping up a couple of weeks ago and said on here that we were shaping up for a potential cold spell a few weeks down the line. 

Of course, it can't be discounted that it all comes to nothing and we 'miss the boat' but from where I'm siqtting thing look very good

Will we get snow in Crewe though or will Congleton and Macclesfield get it as per usual?

[Eskimo]

As others have alluded to, bit of a problem if the low parks itself to the SW of the UK as has been consistently modelled - just ends up drawing in mild upper air (will still be fairly chilly at the surface) and won't prop up the scrussian high. 


 

Edited November 24, 2020 by PerfectStorm

[Met4Cast]

Rather difficult to not feel a tinge of excitement when looking through the EPS members. Plenty of support for blocked Op run. Worth noting that there are still a fair amount of other options on the table but it's hard to deny the marked shift across the board to something a little more exciting today.

The above is positively a cold ramp compared to where we were a few days ago.

[Tim Bland]

Rare consistency- 12z Vs 18z

[Snow lover 2020]

23 minutes ago, PerfectStorm said:

Quite a difference already at +150h. Cold pool nudging into the UK. 

12z                                                               18z

.

Is that a beast on that chart in the east? 

[Eskimo]

1 minute ago, Snow lover 2020 said:

Is that a beast on that chart in the east? 

Nowhere near. It's just far better than the rubbish we've had in over the last couple of years. 

[That ECM]

14 minutes ago, Snow lover 2020 said:

Is that a beast on that chart in the east? 

Snow lover. Have a look at some archive output for comparison. sorry to anyone who saw the pictures before the words

Edited November 24, 2020 by That ECM

[Anthony Burden]

Great to see the charts continue to show some very wintery outlook,

the longer the high holds its ground over Scandinavia the better for cold 

lovers.The added bonus would be Greenland high pressure to join in

then bingo jackpot Charlie.

 

[northwestsnow]

Lovely 18z ...

Then read Exeters update, and wished I hadn't...

Caveat being low confidence.

[Nick F]

A long way off, 7 days away, but nice cold pool moving west over UK on 18z GFS, -7C T850s across southern England and Wales, be cold enough for some snow flurries. Of course take with a pinch of salt, but nice to see...

[Cheshire Freeze]

Pert 5 shows what is possible when the upstream situation plays ball..

One of the most potent N'lys we've had in many years

[weirpig]

Some humdingers in the ensembles  and only just in low res     just shows how things could  develop  as the next few days goes on 

[SMU]

Evening - 

No real surprises on the output today - I highlighted in the post yesterday that there was a high chance of the Easterly flow being reinforced as the jet amplifies again-

That upper air cold pool has persistently been modelling by the GFS to come towards the UK where as the ECM & ICON has been keen to lift it out North West out of Scandi-

Basically all the milder progressive runs have lifted out that cold pool & the cold ones have held better better blocking over scandi forcing the cold pool WSW all beenit at a snails pace!

GFS cold

 

Old ICON warm

 

18z ICON COLD

 

I think before we get to excited about Northerlies we need to see how the reload profiles settle in between 144-168...

S

 

[Allseasons-Si]

late to the party thanks to afters

^Yes good charts

the control drops the trough even further west but as Crewe says, that trough dropping down the NE'ern states of America just vanishes

that iberian low could be a good thing as this would prop the heights up in the Atlantic,a northerly looks odds on at this stage.

Edited November 24, 2020 by Allseasons-si

[weirpig]

Just for fun  but pert 5 goes for -12 uppers across the country from a northerly   with colder air to follow     when was the last time that happened? 

[Allseasons-Si]

2 minutes ago, weirpig said:

Just for fun  but pert 5 goes for -12 uppers across the country from a northerly   with colder air to follow     when was the last time that happened? 

Not kidding JFF,there is only two that show this potent northerly,pert 5 and 30

most of them show benign conditions but cold.