Model Output Discussion - Into 2024

[snowblizzard]

14 minutes ago, stewfox said:

-10c 850s over a lot of south east tomorrow but 3c to 4c forecast  

In the current situation do we need very low 850s to add to instability given high pressure, the wet warm ground ?

-20c 850 line almost made it into SE  January 1987!

I seem to remember Monday 12th it didn't get any higher than -5c during the day with a strong Easterly and heavy snow showers resulting in wind chill around -15c

Absolutely bone chilling, but lovely stuff if you're a fan of severe winter weather!  

 

Edited January 7 by snowblizzard

[Zero Visibility]

1 minute ago, That ECM said:

I agree but it is for ice.

Aye, but ice is better than a wet puddle!!

[LetItSnow!]

1 minute ago, Continental Climate said:

We seem to have been chasing this cold spell since the new year or even before and it's still over a week away. Without being unduly gloomy I'm assuming this hunt for severe cold (-10 uppers) via a greenie high will fail. We are now talking wedges to get the cold in. It's hard not to get dragged in looking at day 10 charts that offer narnia but we must remember that our little islands are probably situated in the worst possible spot in the NH (at our latitude) for cold weather.

I do agree to be cautious and it's always location specific but the -10C uppers are only about 24 hours from being just about over my house with some cute wintry potential. Not exactly Narnia but we're in the game already and to me it looks like a wide array of options, many very good.

[Guest]

12 minutes ago, Penrith Snow said:

"Houston we have a problem"

You don't have to be a depressed pessimist to see things are trending the wrong way, the ENS are underwhelming and the ECM op a shadow of what was promised a few days ago.

Polish it as much as you want but you won't make the models shine, yes still plenty of time for upgrades as the cold spell is still a week away but we need to see the trend reverse soon.

If it is to go TU then I would rather it be now than at +72 which has happened in the past.

People look at upstream developments in the Pacific but for me it's Iberian Heights that's the issue,  the drought in Spain is now serious and unprecedented with little sign of a change anytime soon.

Andy

LOL .... That post is so 20 minutes ago!......Copy and paste for the 12Z's!

[bradymk]

Almost a week ago, the models (gfs in this example) were showing this at +186h for tomorrow. Higher pressure moving northwards and building in around the UK and Ireland. A colder and drier period than recently but with the details to be ironed out.

 

We now have this at +36. The same theme but with differences that have occurred on the way down to t+0 that make a lot of difference to our islands. High pressure still moved northwards giving the drier and colder theme that we expected and had been showing, but the differences have resulted in -12c 850’s tomorrow now across the south.

 

Now although I accept this can work both ways, it is a reminder that we have a long way to go yet. The overall theme of heights to the NW and lower heights over the UK and to our E is still present.

It’s obvious to be frustrated with some of the negative changes to the op runs the last few days, particularly after some of the runs we were having. However after being on here for 11 years, I’m sure we can all agree it is not that unusual on the lead up to a colder spell and often I have found the best upgrades to be once it comes within the +120-144 timeframe. (And of course some of the worst downgrades!).

We are still on track and I imagine a long way from any clarity yet, whichever way that may be. I’m hoping for some improvements back the other way again now as the period of interest moves towards t+144 in the next few days.  

[Richard Fisher]

Many in here saying a dry outlook but wasn't there lows to our SW next weekend which could lead to a snow event as per Met Office update. Have I missed something? Have these lows now disappeared?

[Mark wheeler]

Latest WRF Nmm showing some activity.

[Duane S.]

Too much weight is being given to GEFS trends mid term IMO. The 00z - 06z differences highlight this well. In these non-standard evolving cold spells, there’s often little to be gained by making these too big an egg in the proverbial basket.

There is an enormous amount going on right now, none of which is your standard zonal. Never mind the Shannon Entropy involved downstream from events in the stratosphere…troposphere wise… Pacific ridging interference, that Azores low, inflated Iberian heights, retrogression of the UK high are very difficult to model. They are all intertwined with each other to different degrees as well of course, and not to be taken as isolated entities. 

Then you add in primary long term drivers like ENSO and QBO and short term the MJO route/amplification. Well, good luck being confident on our weather in 2 weeks time.

The take any has to be though, there are way more background signals in our favour than often is the case, so sit back, relax, and try to enjoy the inevitable ups and downs (still to come ), we’re in a really good place still.

[Speedbird]

15 minutes ago, That ECM said:

I agree but it is for ice.

the full warning mentions 'snow'

[Ali1977]

Shower activity quite widely according to this fur tomorrow night 

[Sweatyman]

9 minutes ago, Richard Fisher said:

Many in here saying a dry outlook but wasn't there lows to our SW next weekend which could lead to a snow event as per Met Office update. Have I missed something? Have these lows now disappeared?

yep all gone mate!

[Purga]

Good ENS 06z

FI i 'back to Barty' vomitsville

[saintkip]

14 minutes ago, Richard Fisher said:

Many in here saying a dry outlook but wasn't there lows to our SW next weekend which could lead to a snow event as per Met Office update. Have I missed something? Have these lows now disappeared?

That’s why the latest run is colder, personally I’d prefer the risk of lows coming in against cold air, much more fun

[JimBob]

17 minutes ago, Richard Fisher said:

Many in here saying a dry outlook but wasn't there lows to our SW next weekend which could lead to a snow event as per Met Office update. Have I missed something? Have these lows now disappeared?

The last update mentions heavy rain and milder interludes in the south, so that would suggest the cold will either not get that far south or won’t last long.  Which the models are reflecting this morning. 

[Bricriu]

6 minutes ago, Purga said:

Good ENS 06z

FI i 'back to Barty' vomitsville

Well hopefully at that range it can be treated as cannon fodder.

[tight isobar]

Arome/Arpege precipitation possibly notions @6z.   Anyway it’s very worth pointing out factors here- even in a possible full frontal snow event (lp into cold situ air) it’s nearly always impossible on our maritime island to decipher even near exact geographicals until only hrs out!.. with shower/ streamer scenarios that job only gets harder.  So until around tomorrow morning I’d look but certainly not gage… and my preferred mod at this range will be the Arpege. Get ready for a nail bitting possible classic nowcaster situ.  As regards the bigger picture we’ll await 12z suites for more indications going forward.. it’s true dynamical complexity right now….some shock accumulation likely in such events… let’s see whom get lucky

Edited January 7 by tight isobar

[Biggin]

Windy says sleet and snow se uk Monday

 

https://www.windy.com/-Rain-thunder-rain?rain,2024010812,51.405,-0.044,5

[offerman]

42 minutes ago, Penrith Snow said:

"Houston we have a problem"

You don't have to be a depressed pessimist to see things are trending the wrong way, the ENS are underwhelming and the ECM op a shadow of what was promised a few days ago.

Polish it as much as you want but you won't make the models shine, yes still plenty of time for upgrades as the cold spell is still a week away but we need to see the trend reverse soon.

If it is to go TU then I would rather it be now than at +72 which has happened in the past.

People look at upstream developments in the Pacific but for me it's Iberian Heights that's the issue,  the drought in Spain is now serious and unprecedented with little sign of a change anytime soon.

Andy

Completely agree andy. Good post. 

[Wilxy]

So nice to see a drier outlook, hopefully turning colder along with it!

 

Edited January 7 by Wilxy

[offerman]

Hi Continental climate I couldn’t agree with you more about our little island is the worst place in the whole of the northern hemisphere despite us being quite relatively far north. When you look at Canada all the way across the Japan other places we have to be one of the worst places for cold weather in the winter. You get places much further south than us that get more snow and cold weather.

[Chesil View]

6 minutes ago, Bricriu said:

Well hopefully at that range it can be treated as cannon fodder.

Indeed all nwp is cannon fodder at that range. Even the sainted ECM

[sheikhy]

24 minutes ago, Mark wheeler said:

Latest WRF Nmm showing some activity.

@Battleground Snow

[nick sussex]

2 hours ago, Vortex3929 said:

Regional thread says rain. Temperatures and dp are too high still. 

A little disappointing to read that the ECM still isn't being helpful for the cold spell. Adding further to the points raised on why we are seeing "down grades", I'm rehighlighting this point as I think it's quite valid 

Now I'm not an expert in this field of model watching, but I do read here a lot. 

Haven't we had to rely on an the Pacific jet to an extent (EAMT etc) ? And this jet somehow matters to our weather ( as per Tamara and met4cast?)... so if there is model spread happening over in the Pacific (and I may be very wrong here!!!! This is purely guess work by me)... would they same model spread not have a similar knock on effect downstream so to speak and there for cause our models to possibly be exhibiting some kind of change or disagreement?

Yes . The two areas mentioned in their discussion have a large impact on what happens re any northerly here .

Uncertainty in the east Pacific is related to what happens with that Pacific Ridge and we’ve seen the knock on effects especially in terms of the ECM output . The amplitude of the pattern over the USA and Canada effects the building of any Greenland or North Atlantic high .

For this reason I’d not be too downbeat over cold prospects just yet . 

More runs are needed ! We just don’t know what the correct evolution is yet .

[Cambrian]

Comparing the 0z runs, it’s interesting that the GEPS is again keeping the Arctic Canada heights, extending into southern Greenland, all the way through to day 14, while the GFS is moving the tropospheric PV there. Conversely, the GEPS has two lobes to the PV linked through Greenland to Svalbard.

GEPS / GFS

 

Huge differences downstream over the Atlantic as a result of course, with the GFS pepping up the jet stream and blowing through the Scandinavian trough. 

But notice the upper trough through Iberia on the GEPS and the lack of any heights on the GFS, and the southeastward dive of the contours through or to the west of Iberia on both models. 

 

This suggests that a good possibility of a southerly tracking jet stream is well and truly there in both scenarios. 

It is clearly the Arctic that is in enormous flux in the models and it could well be that these two solutions are close to representing opposite ends of the range of likely location of the PV.

 

I have concerns about the EPS due to the rate of change in the mean pattern between days 12 and 14 looking far too rapid. An abrupt unidirectional collapsing of the pattern like that would be surprising. 

 

A GEM / GFS halfway house might position the weakened PV to the north of Greenland just our side of the pole with plenty of scope for development of meridional and blocking patterns later in the month, as indicated in yesterday’s EC46 weather regimes, following a brief NAO+ signal for a few days from day 14.

So some “tethered speculation” - blocked now, the retrogression, then cold, a relatively brief relaxation to something a bit more mobile, which could be battleground and snowy, then back to blocked, the jet stream quietening down again, leading to good scope for a further phase of retrogression and potentially further plunges of Arctic air.

We’re certainly finding more and more that there’s nothing ordinary about this January! 

[MJB]

11 minutes ago, JimBob said:

The last update mentions heavy rain and milder interludes in the south, so that would suggest the cold will either not get that far south or won’t last long.  Which the models are reflecting this morning. 

It's clearly suggesting a battleground scenario, how far north wouldn't be determined until 24/36 hours before. That's if any fronts ever get that far into the UK from the S or SW