Model Output Discussion - New Year and Beyond

[Allseasons-Si]

You might think that this is an awfull chart at 306 but i will tell you it isn't,...get the heights pumping through the UK and to our NE would be a great strat buster,...watch it evolve.

and just to add,...if you are worried about the tpv to our NW,..don't,...i have seen many a cold spell evolve whilst that tpv is in situ,the downstream amp from that would bolster heights to our NE as that chart stands

i am loving this search for the next cold spell,...we have had 2 so far but the lack of snow for many,...i get it because not everyone will get snow from a cold spell as the air is dryer and clearer

we still have a ticket or two and mid Feb> i have a golden ticket saved as the mjo races through to phase 6-7,...i hope that i don't have to sell it.

 

Edit: just to add,...where is @MATT TATTOO,i hope his dad is OK.

Edited January 22, 2023 by Allseasons-si
typo/added charts

[Eagle Eye]

It's looking less and less likely that a major SSW will occur but we're going to get a fairly weak Strat Vortex for a time I suspect so that's a small plus. It's still possible but very unlikely at the moment in my opinion. Things trending in the wrong direction but not unsalvageable so it's still one to keep an eye on. Anyway, a little animation via Dr Simon Lee from a few days ago, cannot stop watching it...

 

 

[tight isobar]

59 minutes ago, Allseasons-si said:

You might think that this is an awfull chart at 306 but i will tell you it isn't,...get the heights pumping through the UK and to our NE would be a great strat buster,...watch it evolve.

and just to add,...if you are worried about the tpv to our NW,..don't,...i have seen many a cold spell evolve whilst that tpv is in situ,the downstream amp from that would bolster heights to our NE as that chart stands

i am loving this search for the next cold spell,...we have had 2 so far but the lack of snow for many,...i get it because not everyone will get snow from a cold spell as the air is dryer and clearer

we still have a ticket or two and mid Feb> i have a golden ticket saved as the mjo races through to phase 6-7,...i hope that i don't have to sell it.

 

Edit: just to add,...where is @MATT TATTOO,i hope his dad is OK.

Absolutely- but even b4 a “maybe mjo” twist.. you only have to go through multiple frames via raw output in the 850 hpa plots... to note something is likely brewing- and or- opportunity sync-theres nil mobility of any notable reference WHATSOEVER!- and as obvious, as momentum plays out naturally- that HP could indeed be a trigger objective... for raising many an eyebrow... as placement becomes more set in motion!!the nxt “7 days”- are starting to intrigue me vastly now......edit: another worthwhile looking decline in member/ leader sets... @ London 18z - the + notions looking ever more vunrable!!.. @ interesting! ....Currently -6 here @ Uxbridge dense fog hard frost... I’m not expecting no big warm up in these parts.. for sometime... if at all - short / mid range!!!

Edited January 23, 2023 by tight isobar

[Cold Winter Night]

1 hour ago, Allseasons-si said:

the NWP have been towting at this(control mainly),and i just want to ask a question as it's totally over my head,...do NWP'S(the models) take into account the strat warmings?

i am sure they lag or lack on the subject and i have seen a quick turn in the models when they catch up.

Well, yes. After all, the stratospheric charts and profiles shared by many on here come from the same models as the tropospheric output.
Without the models we would not have known about the possibility of a strat. warming in the next few weeks until it appeared in observations just days ago.

So if the warming happens early enough on the run, you can see the modelled influence of it descending (or not) afterwards.

Caveats are that there is less observational data than from the troposhere to begin with, and, depending on the model design, often less resolution and less vertical layers.

The thing about models having to catch up with strat warmings is more that the sudden time, location and height sensitive changes (from a stratosphere that is usually very stable compared to the troposhere) can make model solutions go all over the place.

Think of a ball rolling down a field. It's not too difficult to predict where the ball will be 5 seconds from now. But then add a player (downwelling wave) that will kick it along its way, but you don't know exactly when, from what direction and with how much force yet, nor do you know if another player (like a blocking high) will be in the right time and place to also hit the ball. Now forecasting the location of the ball 5 seconds from now becomes a more difficult task...

[Rain All Night]

[PiscesStar]

Good Morning All!  

A very cold outlook from the gfs this morning. Promising to say the least for February!!  

[carinthian]

23 hours ago, carinthian said:

Morning all. Latest ECM run still has winter in its reach to start the new month. Looks like cold intensity building again over NE Europe and could easily develop into a blocking scenario close to the British Isles.  Think still plenty on interest this coming week to watch developments. At the moment rock solid agreements in the models at 96t .

c

 

Morning all from a very snowy Austrian Alps. Just an update regarding the above post. ECM continue to show promise for early Feb. Two things I like about that chart below is the Scandinavian trough continues to extend its influence into Europe with a snowy set up and the UK increasingly aligned to the colder side of the battle zone in air masses. Again , I think we could see some nice winter charts produced as this week progresses.

C

[Rain All Night]

The GEFS and GEPS suites both seem to support narrative that the high will sink very slowly towards Europe. The CFS is giving up on its signal for the high to go up to Greenland.

EPS plumes for Poole don't show a mild outlook:

[Drifter]

If we could just get that damn chunk of pv near Greenland to relax even a little we could be in serious business. 

[nick sussex]

The ECM is much improved in its later output from last night.

The day ten shows the latest upstream low facing a struggle to move east as it begins to sharpen up.

Earlier it almost tries to develop a slider between day 8 and 9.

Essentially this is turning into a battle between the main PV located over ne Canada and forcing from the ne .

So the PV feeds energy into low pressure which deepens wants to move more ne against that forcing .

The PV is struggling more by day ten as it’s becoming stretched , much depends on whether we can see more amplification develop across Canada .

This can engage the PV and latch onto it and can help develop more amplitude over eastern Canada .

The effect is to direct more energy se as you can see in its day ten .

 

Let’s hope this isn’t another false dawn ! 

[Daniel*]

Noteworthy cold this morning guys thought I’d share Heathrow fell to -8.3C this morning. It is the coldest January temperature since January 1987 beast from the east. Also the lowest temperature since December 2010.

[Chesil View]

Some nudges in the right direction in this mornings modelling. Let's hope it continues.

Edited January 23, 2023 by Chesil View

[Paul_1978]

This may have already been mentioned, apologies if it has. Marco from the Met Office tweeted that if a warming does occur then it is expected to have no impact on our weather as the strat and trop are not coupled. 

 

[frosty ground]

6 minutes ago, Paul_1978 said:

This may have already been mentioned, apologies if it has. Marco from the Met Office tweeted that if a warming does occur then it is expected to have no impact on our weather as the strat and trop are not coupled. 

 

What you have written and what the tweet states are not the same.

have you missed a tweet?

[billy]

35 minutes ago, Daniel* said:

Noteworthy cold this morning guys thought I’d share Heathrow fell to -8.3C this morning. It is the coldest January temperature since January 1987 beast from the east. Also the lowest temperature since December 2010.

Yes -7 here again last night. Although we've had no snow this winter, I can't remember the last time we had a winter with so many hard air frosts with temps below -3 ....Yet strangely enough I saw some daffs in flower in the village yesterday

 

Edited January 23, 2023 by billy

[Stuie]

In just 3 days time, Mogreps starts a scatter fest on the 850`s. Frost could be the new snow.

[Purga]

Not perfect but a pretty decent output this morning.

This is far better place for the jet than roaring away to the north of us !

[jethro]

15 minutes ago, billy said:

Yes -7 hear again last night. Although we've had no snow this winter, I can't remember the last time we had a winter with so many hard air frosts with temps below -3 ....Yet strangely enough I saw some daffs in flower in the village yesterday

 

I wouldn't pay any attention to the daffs, so many varieties have been bred, it's now possible to have them flowering from December all the way through to April. Nothing to do with weather, depends upon the variety.

[Benny123]

45 minutes ago, Daniel* said:

Noteworthy cold this morning guys thought I’d share Heathrow fell to -8.3C this morning. It is the coldest January temperature since January 1987 beast from the east. Also the lowest temperature since December 2010.

-8c across the South East, +10c across NW Scotland.. a reverse contrast for once! 

[andymusic]

GFS overnight ops run 00z looking colder with pm and northerly shots pushing into the UK - certainly a move in the right direction - let's see if this continues or gets any better with subsequent runs 

2 minutes ago, Benny123 said:

-8c across the South East, +10c across NW Scotland.. a reverse contrast for once! 

yep - the highlands have moved to London lol

[northwestsnow]

Better runs this morning word of warning though, the EC mean is crap so we'll need to see clusters for better guidance..

[Rain All Night]

Just now, northwestsnow said:

Better runs this morning word of warning though, the EC mean is crap so we'll need to see clusters for better guidance..

Better guidance not forthcoming!

[Drifter]

9 minutes ago, RainAllNight said:

Better guidance not forthcoming!

Does one cluster indicate rock solid certainty? Or the opposite?

[Rain All Night]

7 minutes ago, Drifter said:

Does one cluster indicate rock solid certainty? Or the opposite?

I will defer to @Mike Poole if he knows any better, but I think it's the opposite:

"When the ensemble distribution is sufficiently homogeneous the cluster algorithm cannot partition the ensemble in a meaningful way, for these cases the ensemble member that better represents the ensemble mean is shown." - says the blurb beneath the cluster charts on the ECM website

Actually wait, "homogenous" means similar doesn't it... so maybe it does show a strong consensus?

Edited January 23, 2023 by RainAllNight

[Mike Poole]

10 minutes ago, Drifter said:

Does one cluster indicate rock solid certainty? Or the opposite?

On occasions one cluster can mean near certainty, especially if in the early timeframes.  More usually, in my experience, though, it means the exact opposite.

4 minutes ago, RainAllNight said:

I will defer to @Mike Poole if he knows any better, but I think it's the opposite:

"When the ensemble distribution is sufficiently homogeneous the cluster algorithm cannot partition the ensemble in a meaningful way, for these cases the ensemble member that better represents the ensemble mean is shown." - says the blurb beneath the cluster charts on the ECM website

Actually wait, "homogenous" means similar doesn't it... so maybe it does show a strong consensus?

Here, homogeneous is more likely to mean ‘not lumpy’!  So it is not saying there is little uncertainty, just that the algorithm cannot discern a small number of distinct, different evolutions within the ensemble set.  And this can happen when there is very large uncertainty, as well as when there is good confidence in a single evolution.