Model output discussion - deep cold inbound?

[TSNWK]

1 minute ago, sheikhy said:

What you think about the models this morning blue?!good or bad to your taste?!

There is a certain irony in that @sheikhy responded to that post from @bluearmy

[Griff]

3 minutes ago, Paul said:

Just a quick one, locations should now be displaying on posts if you're on a mobile.  

To confirm, yes, a useful addition, thank you. 

[Jarrow Posh]

15 minutes ago, sparky1972 said:

good morning all, well as a rule of thumb for me is to look at the met office and bbc online forecasts to see their predictions and i have to say they are awful for cold and snow for here, chilly, sleety but not alot of snow, all very disappointing, then i come to hear to read everyones views and expected to read its all gone wrong overnight in the models, but i am glad to read we are still in with a chance of snow up and down the country so not to write of the chances yet. keep up the good work guys and gals.

I think that the media organisations you mention will always hold back with their warnings until it is nailed on.Apps are also notoriously slower updating and imo a waste of time.

The MO will be preparing their early warnings but we are talking late Saturday,into Sunday before the majority of the country start to feel the effects of the easterly and it associated risks as highlighted by all the major models now.

I know your location well and I'd imagine once the cold comes later this weekend you shouldn't be concerned about a lack of snow showers coming along.

Enjoy!

[Scott Ingham]

6 minutes ago, Griff said:

Morning Scott, 

Good to have you back. If I could find them (too much effort now to search the archives here) there would be many a post from December into January, that you posted which I believe touched on teleconnections, tropical forcing and the like that I have been keeping a close eye on (albeit with limited knowledge and experience), all of which alluded to and explained why it is this weekend onwards holds so much promise. 

Nothing was ever set in stone, and I remember you caused quite a stir. I know many were hoping for something instantaneous in January (those in the North of the UK, or perhaps Madrid and Japan would say the early predictions made by some, verified well). 

My personal pet indicator for this winter was the Atlantic Hurricane season and early comments by Marco Petanga and Gavin P regarding Accumulated cyclone energy (ACE), specifically in an above average to hyperactive hurricane season. 

Who knows how everything truly interacts and comes together? A fascinating winter nevertheless, and hopefully a chance across the coming week for everyone to see a flake or two, or even perhaps a light dusting?

Probably just the coffee talking now... Love you guys, one and all

 

Morning mate will only be making fleeting visits but yes i called this period middle of December with the two periods in December and January just gone as appetisers.

Its taken 4 bites of the cherry so to speak.

Its been a season of fluctuating peaks and troughs in tropical energy and consequently rises and falls of relative angupar momentum.

This time weve had everything come together at the right time!

1) We have a mature SSW nearly 30days post onset of the 5th of January with two seperate warming events embedded after the first event with an atmosphere now fully coupled through all levels

2) We have the 3rd rise in AAM im 40 days with each time a polar field becoming more sensitive to each wave break (we have a potential 4th rise end of february beginning of March)

3) The MJO wave was forecast to hit the western pacific early february ro finally assist height rises in Scandi then Greenland that in previous attempts failed to gain a foothold which as the fall in momentum dropped saw high latitude blocking sink

I posted in the regional thread 2 days ago to talk up the chances of scandi height rises into week 2 due to a portiom of the vortex firing up the atlantic. Often southern tracking lows are precursers to height rises in iceland amd scandinVia. Ive been emcouraged to see this only getting played with a little yesterday and the GFS to build Scandi rises towards the back end of the run. I think just like the met the cold is here for a minimum of 2 weeks potentially longer

[kold weather]

7 minutes ago, bluearmy said:

I see the general  ‘bi polar’ reaction to each suite remains consistent in here

steady as she goes with each run swinging back and forth within an envelope which should become smaller as time ticks by ...

it’s hanging on a bit too large at the moment !

 

If nothing else it won't be too long before we all depart towards the regionals, which should at least calm this thread down a little as we vent or praise the runs on the regionals!

I think though the odds are now edging towards the south also joining in, which is clearly going to be a relief to a great many. Especially those that have been screwed over multiple times already this winter.

Probably one more day before the confidence will really increase for at least Sunday-Monday. Beyond that still some real uncertainty, though there does appear to be big signs of a lowering pressure to our SW, which always brings a risk of fronts coming in from the SW.

Also, I suspect the high pressure area to our north will probably hold longer than models expect, something like GFS perhaps.

Edited February 3, 2021 by kold weather

[drgl]

5 minutes ago, Paul said:

Just a quick one, locations should now be displaying on posts if you're on a mobile.  

Yep. A welcome update. Thanks!! Those saying they watch the BBC. Last weekend they forecast snow here, we had rain. Two weeks ago they forecast rain..we had SNOW!

Enjoy the models but you won't know until the DAY!

Edited February 3, 2021 by drgl

[jamesgold]

The models are poor at picking up convection at this range especially. For anyone down south I think we know streamers can set up at quite short notice - get the cold in and the snow can follow etc etc 

[Tim Bland]

Great to see locations on my iPhone now! Makes it much easier to decipher people’s reactions. 

still a way to go to persuade the GEFS of the longevity...but it’s a start! 

[Paul_1978]

5 minutes ago, Paul said:

Just a quick one, locations should now be displaying on posts if you're on a mobile.  

They are indeed - cheers Paul!!

[Battleground Snow]

Looks like that low at 144 was modelled too far North compared to the mean, or maybe it won't even form at all

[Griff]

4 minutes ago, Tim Bland said:

Great to see locations on my iPhone now! Makes it much easier to decipher people’s reactions. 

still a way to go to persuade the GEFS of the longevity...but it’s a start! 

Definitely an improvement from the doom of 48 hours ago

[Tim Bland]

UKV going for masses of convective showers for eastern areas on Sunday ..

[nick sussex]

Good agreement on the overall pattern for Western Europe but the all important detail for the UK still remains elusive . Blocking shifts more nw over time and a surface high to the ne helps to keep the jet further south.

Northern areas members should be least stressed because of the high margin for error there . The stress factor rises as you head further south because the models are reluctant to take the coldest air sufficiently south to allow for a higher margin for error .

Theres lots of snow potential , heavy snow showers and frontal snow but the latter aspect can’t be resolved yet.

[Cloud 10]

19 minutes ago, Kreftysoton said:

Loving the positivity this morning, most seem bullish about the cold spell. Can someone tell me why both BBC and Met have downgraded cold already for my part of the world? (Soton)  Sat - Mon was 3c max now showing 6s and nxt week up to 9/10?  Do they use different models than the ones discussed on here? 

Those weather apps. are hopeless.

Monday afternoon temps.

 

[Paul_1978]

Absolutely phenomenal overnight runs. The biggest upgrade for me this morning is this - as of last night, the low approaching from the west was unable to progress eastwards beyond the south coast into Europe, giving us a slack south westerly flow, and most models were showing this. Basically the easterly lasting around 4 days. However.....

..... as of this morning the low is sliding under the UK on Weds into Thurs, maintaining the easterly feed, and no doubt giving snow to boot. 

So that’s why I think the overnight runs are positive! 

[Paul]

The UKV is still steady in bringing the cold south over the weekend, with snow showers from the east. And whisper it quietly, but this also includes the south!

  

  

The UKV is the Met Office's operational hi-res deterministic model - more info here:

Numerical weather prediction models

WWW.METOFFICE.GOV.UK

---

The Unified Model is run operationally in a number of configurations for weather forecasting at the Met Office.

 

[Guest]

GFS, ECM & GEM ensembles all seem to show a decent cold spell in the south for 4-5days, I'm sure convection and a the odd polar low may well be be thrown in once we actually get to the business end of the weekend. Being very IMBY its still tricky to get a decent fall of snow in south Dorset from an easterly, really need frontal activity pushing up from the south with an easterly undercut. Looks like at the moment its only a relatively short cold spell down here with all the ensembles ushering in milder conditions from the 12th however sometime these spells do have a habit of extending themselves by a day or two.  

[Stephen W]

2 minutes ago, nick sussex said:

Good agreement on the overall pattern for Western Europe but the all important detail for the UK still remains elusive . Blocking shifts more nw over time and a surface high to the ne helps to keep the jet further south.

Northern areas members should be least stressed because of the high margin for error there . The stress factor rises as you head further south because the models are reluctant to take the coldest air sufficiently south to allow for a higher margin for error .

Theres lots of snow potential , heavy snow showers and frontal snow but the latter aspect can’t be resolved yet.

I 100% agree with this. The margin for marginal in the south remains! The placement of the low looks to me like it could go right to the wire with 50-100 miles making all the difference which is nothing in the scale of things. So, any of us in the south will have to live on our nerves for a few days yet. Some luck is required. Overall though, there is more cross model agreement this morning so that’s a positive.

[ANYWEATHER]

Southern Britain in for a belter of classic snowy cold looking at the models this morning. Anyone who loves classic historical like bitter cold snowy weather is in for a treat . I would imagine that the wind chill especially for southern Britain next week will literally take your breath away. Obviously still a way to go so some caution still needed but overall an upgrade in model output.....

[nick sussex]

Just now, Stephen W said:

I 100% agree with this. The margin for marginal in the south remains! The placement of the low looks to me like it could go right to the wire with 50-100 miles making all the difference which is nothing in the scale of things. So, any of us in the south will have to live on our nerves for a few days yet. Some luck is required. Overall though, there is more cross model agreement this morning so that’s a positive.

I think prospects have improved for southern members overnight . Looking at the ECM ensembles that’s better than last night . Overall a good start to the day for coldies throughout the UK .

 

[Rollo]

1 minute ago, nick sussex said:

I think prospects have improved for southern members overnight . Looking at the ECM ensembles that’s better than last night . Overall a good start to the day for coldies throughout the UK .

 

Have you disbanded your committee yet or are they still on standby Nick.

[sebastiaan1973]

Latest Plume De Bilt. Control and Oper are no more or less in line with the rest of the members.

Dewpoint and Winddirection.

Edited February 3, 2021 by sebastiaan1973

[Speedbird]

6 minutes ago, nick sussex said:

I think prospects have improved for southern members overnight . Looking at the ECM ensembles that’s better than last night . Overall a good start to the day for coldies throughout the UK .

 

A southerly correction is quite common and i'd not be surprised to see further adjustments south to totally negate marginality further for southern members

Edited February 3, 2021 by Speedbird

[nick sussex]

Just now, Rollo said:

Have you disbanded your committee yet or are they still on standby Nick.

The meeting has been rescheduled for this evening ! By then I think we should have better agreement on the detail . It’s looking interesting , I’m really enjoying seeing this unfold from here in France .

[Tim Bland]

Getting a feeling of deja Vu flicking through the models and left praying the GFS is correct!!

If I’m being really picky ... I’d like the convective Easterly to last a bit longer. Although the easterly flow last a while most models are only showing snow showers from the east on Sunday and Monday. After that most models (except GFs) have the energy coming from the west which ends in a snowy breakdown Weds night / Thurs morn, then it’s back to something more normal by the end of the week.

My gut tells me models are too keen to allow the Atlantic to break through the cold barrier and that low will end up further south. If that happens then the GFS op isn’t as mad as it seems !