model discussion Model output discussion - closing in on Winter

[bluearmy]

3 minutes ago, MATTWOLVES said:

Very respectable mean si..further on and we get huge scatter as would be expected...plenty of cold options remain though,so anyone who thinks it's a quick cold snap,then a return to mild zonal could be very much mistaken.

And there you have the definition of spaghetti! 

[MATTWOLVES 3]

Cracking start guys...Blocking in place come months end! 

Edited November 18, 2021 by MATTWOLVES

[northwestsnow]

Ec 46 is interesting tonight...

Lots of HP and hints of a scandy block at Christmas...

[northwestsnow]

The run up to Christmas looks dry ,and chilly...

No doubt the positioning of any high pressure will dictate ground temps but l mid Dec is a pretty good time to get Frosts under a high.

Edited November 18, 2021 by northwestsnow

[Adam lufc]

Guys n girls please can we stop the 'its only november and winter has startrd yet'. These get thrown up every year and as proven during the season that it doesnt matter when it is, if there is potential we need to take it as months can go by with relentless mild damp weather and before you know it, spring is here. We need every opportunity to go our way as best as possible. Tonights charts dont look too bad but typically taken away the cold fest that was originally on offer, esp just as you tell the rents n children lol. Lets see what 18z throws up. For now keep the faith.

[MATTWOLVES 3]

3 minutes ago, northwestsnow said:

The run up to Christmas looks dry ,and chilly...m

I try not to look that far ahead mate...my nerve never holds out

But we see know signs of a raging West to East pattern! Perhaps it's about time we dropped the word zonal,for perhaps Horizontal!

[January Snowstorm]

From my experience when models back off something they usually go the other direction altogether. In this case it's a chop and change of the same general theme I.e. cold. Again from years of model watching usually when it's just a variation of a theme it then goes back to its first idea and upgrades quite a bit.

So my punt is the wobbling is coming to an end and huge upgrades are imminent!

[Ali1977]

This is interesting , many EC ENS retain the cold beyond day 10. Op and control much warmer. 

[northwestsnow]

One stand out looking at the ec46 is the low pressure anomalies to our south ...

I strongly believe getting as much energy south into Europe is vital for  UK fortunes...

[Man With Beard]

1 hour ago, ICE COLD said:

Well the mean still looks pretty bloody good my friends

Having seen that mean ... I think it's going to be a classic nail-biting few days in this forum. The ECM mean slightly favours a colder solution, I'd say.

[bluearmy]

Largest 2 week 4 ec 46 clusters are not without interest ……

 

[Polar.]

6 minutes ago, January Snowstorm said:

From my experience when models back off something they usually go the other direction altogether. In this case it's a chop and change of the same general theme I.e. cold. Again from years of model watching usually when it's just a variation of a theme it then goes back to its first idea and upgrades quite a bit.

So my punt is the wobbling is coming to an end and huge upgrades are imminent!

In my experience wobbling usually leads to a head on collision with disappointment lol

[Uncertainty]

Seen as both the short range and long range  (seasonal +NAO vs statistical - NAO) are shrouded in mystery at present I thought it might be time to look to the extended range and ask what’s next after this Atlantic ridging spell.

The latest EC46 takes the MJO towards phases 6 and 7

In a Nina December, the composites for those WP phases come out like this:

 

 

CFS weeklies bear some resemblance, especially at week 4 given the lag

The JMA 17-30 day also has heights near the U.K but biased more to the west (we’re in the top left!)

Week 4 then on the EC46 comes out like this

An arctic low pattern over the states and a U.K. high

Week 5 looks intriguing with lower heights into S Europe and a small hint of a ridge over the top towards Scandi

The above represented well with the Blocked regime favoured through mid  December 

 

Mr Griffiths has kindly posted the strat forecast and it looks strong steady but no intense period of Vortex Intensification suggested at present. Coupling, or lack thereof is beyond me pay grade but the longer we go without Ural blocking the more likely that sooner or later the seasonals will win out and a Zonal January will ensue.

It’s impossible in my opinion to go beyond this because there is such a stark disparity between the favourable (for cold) background signals and associated -AO and the predictably flat signal from the seasonal models (bcc excluded)

This chart, taken from the brilliant World Climate Service shows what previous years with similar tropical SSTs produced 

You can add

- A possibly trending east based moderate Nina 

- Mature EQBO

- Coming out of low solar

- Pretty decent November Asian snow cover extent 

- (According to Judah Cohen) favourable sea ice anomalies

- Even Accuweather think it’ll be cold 

Thats quite the list of cold factors.

But yet the long range modelling is paddles not sledges
 

But they maffed up last year, and missed the BFTE, so it’s most definitely all to play for. But until we see how December plays out, it’s unknowable. 
 

What we can glean is that:

- Next week + week after look cold, perhaps not very snowy but still unresolved 

- Mid December looks like high pressure will be close to the U.K. 

- After Xmas and beyond are a total mystery.

Huge potential for both cold and disappointment.

[Mike Poole]

So where are we on 18th November, exactly?

Nothing remotely zonal or off the Atlantic for the foreseeable, and beyond, if that isn’t a paradox!  Bank.

We have an envelope of possibilities about how the next week might pan out and it includes some cold, and indeed some potentially very snowy, options for some regions.  That envelope includes the slightly underwhelming GFS, and ECM, but also the bullish GEM and JMA, and that range is exhibited by the clusters as well.  Even the most underwhelming ensemble member would be way colder than standard fayre for this time of year, that too needs to be factored in.  

Although some models have predicted a cold hit from the north with a wide margin of uncertainty, some have been much narrower, and time of year does have something to do with this, I think.  

One thing we should also bear in mind is that the NH is not primed for a return to zonal anytime soon.  So there will be multiple opportunities in this whilst the hemisphere grows ever colder, what might be marginal now for snow will not be in another fortnight.  And to pick a chart for the longer range from the most sneezed upon run of the 12z, the GFS, the potential in FI is eye catching - GFS 12z T300:

We have phase 1 of the cold chase nailed, lock out the Atlantic.  So we move to phase 2, get the cold in!  And it may be done and dusted in a week or may take a little longer.  Then we move to phase 3, opportunities for snow.  One for another day, surely, let’s walk before we can run…

All the best, Mike.

[stodge]

Excellent post from @Uncertainy and plenty to mull over.

The notion of strong heights to the east and north east has been mentioned more than once - the classic stand off charts between continental cold and oceanic mild airmasses leaves the UK in an often benign S'ly airflow. We can expect heights to wax and wane and when they are closest and strongest we can advect some continental cold.

An even rarer phenomenon these days seems to be the UK anticyclone. One of these mid winter can bring ice days thanks to significant inversion and it's not to be sniffed at if you want cold though not much hope for snow. The key then to what looks an increasingly dry winter is the position and orientation of any HP. Will we be looking east and if so how far? 

[MOF]

32 minutes ago, Polar. said:

In my experience wobbling usually leads to a head on collision with disappointment lol

Drink less, chances of disappointment get less

[Allseasons-Si]

Nice update there from the ec46 thank you^^

Here is my round up as promised,...longish post coming up

The latest anomalies for day ten:-

the cpc still has a huge Atlantic ridge with upper winds NNW into the UK, Aleutian low with strong Pacific jet(where we want it and not in the Atlantic),...keep it there

Eps:-

i have done a scribble on the 500mb chart just to explain where we are,most of the high pressure seems to be on the western and eastern hemisphere with low pressure NE Pacific/Alaska and from the Urals down into most of NW Europe and SW,...temps well below average in the same said places,the green line roughly shows where most of the amplification is

here are the latest day ten means from both the ECM and gefs

500mb,850's and Geopotential heights,i would say that the gefs is slightly better than the ECM in regards of the 850's clearing the south

gefs mean day ten jet and as you can see(like i explained above)the most of the jet stream is on the other side of the globe in the north Pacific,...almost non existent in the Atlantic

op and control for the same time...

and i wonder why the Atlantic is dead,...because the NAO is or soon to become anyway,the AO is to slow down too and don't worry about the uptick at the end,...it as a habit of doing this

now i would just like to point out that we have great synoptic charts that we have not seen for a good while and some of us may see some snow but don't moan if you don't get any because this will be a bonus as it's only November and winter is a few weeks away

here is a couple of charts to compare,...which one would you like the most?

this horrid one or this one from the gfs 12z at 192 today.

OK the 18z is rolling out now. 

[damianslaw]

32 minutes ago, Uncertainy said:

Seen as both the short range and long range  (seasonal +NAO vs statistical - NAO) are shrouded in mystery at present I thought it might be time to look to the extended range and ask what’s next after this Atlantic ridging spell.

The latest EC46 takes the MJO towards phases 6 and 7

In a Nina December, the composites for those WP phases come out like this:

 

 

CFS weeklies bear some resemblance, especially at week 4 given the lag

The JMA 17-30 day also has heights near the U.K but biased more to the west (we’re in the top left!)

Week 4 then on the EC46 comes out like this

An arctic low pattern over the states and a U.K. high

Week 5 looks intriguing with lower heights into S Europe and a small hint of a ridge over the top towards Scandi

The above represented well with the Blocked regime favoured through mid  December 

 

Mr Griffiths has kindly posted the strat forecast and it looks strong steady but no intense period of Vortex Intensification suggested at present. Coupling, or lack thereof is beyond me pay grade but the longer we go without Ural blocking the more likely that sooner or later the seasonals will win out and a Zonal January will ensue.

It’s impossible in my opinion to go beyond this because there is such a stark disparity between the favourable (for cold) background signals and associated -AO and the predictably flat signal from the seasonal models (bcc excluded)

This chart, taken from the brilliant World Climate Service shows what previous years with similar tropical SSTs produced 

You can add

- A possibly trending east based moderate Nina 

- Mature EQBO

- Coming out of low solar

- Pretty decent November Asian snow cover extent 

- (According to Judah Cohen) favourable sea ice anomalies

- Even Accuweather think it’ll be cold 

Thats quite the list of cold factors.

But yet the long range modelling is paddles not sledges
 

But they maffed up last year, and missed the BFTE, so it’s most definitely all to play for. But until we see how December plays out, it’s unknowable. 
 

What we can glean is that:

- Next week + week after look cold, perhaps not very snowy but still unresolved 

- Mid December looks like high pressure will be close to the U.K. 

- After Xmas and beyond are a total mystery.

Huge potential for both cold and disappointment.

Looks very Dec 96.

[weirpig]

Flatter on the 18z  could be further east then the 12z

[Griff]

1 minute ago, weirpig said:

Flatter on the 18z  could be further east then the 12z

Just thinking how the GFS is different to the other models with regards to the heights not making much progress out over Greenland

[Allseasons-Si]

On 18/11/2021 at 22:13, weirpig said:

Flatter on the 18z  could be further east then the 12z

It is not flatter,...there is better ridging into the Gin corridor and W Greenland that should help the second bite of the cherry.

[Ali1977]

It was the strength of the PV around day 8 to our NW that helped push things too far west - what is noticeable is that the 18z has weaker PV - this could help the sliders come down at a more vertical angle. Looks better .

WAA also more vertical and pushes further north 

Edited November 18, 2021 by Ali1977

[sheikhy]

4 minutes ago, weirpig said:

Flatter on the 18z  could be further east then the 12z

Nope the same pretty much!but the main thing is its not gone the same way as ecm at 144 hours!!yeh less heights across southern greenland but boy that low over the uk did the damage!!the gfs 18z does not have it therefore its colder more widely with a clean flow from the north!

[Mike Poole]

Pub run T144 vs 12z T150:

Better alignment in the Atlantic, and just a smidgen better low heights into Europe compared to the 12z.  

[tight isobar]

Yes better ridge via the 18z as emphasised through the 1.5 window