Model Output Discussion - Christmas and New Year

[sheikhy]

Ecm same as 12z yesterday!!gfs p and control same as yesterday!!ukmo same as 12z!!ecm mean bloody fantastic!!bring it on!!!gfs op you can go do one please!!

[Sky Full]

After storm Bella last night, which didn’t seem to deliver the killer punch some of the models were predicting, here are the 6 day charts for the main models (+144hr) this morning....

                500s.                                850s

UKMO     

ECM        

GFS          

GEM.      

There is already some disagreement in the placement of different features but they all agree on keeping some sort of Atlantic ridge in place between the Azores and Iceland thereby trapping some colder upper air over the UK for the next six days at least.  Not necessary a snow machine set-up but poised to bring some snow in places on high ground perhaps, or later on to allow those North American lows waiting in the wings to break through and sweep it all away.....  Whatever it eventually delivers, this is a more promising wintery-looking start to January than we have seen for a few years.

 

[BalderstoneNick]

1 minute ago, fellmike said:

Sorry for being thick but why is gfs showing a sw and ecm showing a ne wind in ten days time or am i reading it wrong?

Basically none are that accurate at 10 days, you will see the GFS on its own swings massively from run to run at that range. Best you can hope for is a general pattern,  Try to look at GEFS ensembles or the anomalies 

[SLEETY]

31 minutes ago, Weather-history said:

Here was ECM 0z from 17th December for today

GFS 0z 

GEM 0z

 

The reality

 

oh the biggest example of why latter ouput is not worth taking too much notice of.

Can you post todays gfs 00z ouput then post the actual reality in 10 days,for a good laugh.

Actually start from 144hours and every day from then and post actual reality ...

Edited December 27, 2020 by SLEETY

[Scott Ingham]

8 minutes ago, swfc said:

Thanks For Your Kind Words MAT morning. very slack 7 days coming up imo with cool/cold air stagnating over the UK. showers and surprise areas of low pressure with a wintry mix in places. ec oz shows the fluidity and slight uncertainty going into fi along with the other models. I don't see anything in the reliable showing anything of note "altho compared to recent years that's not difficult" but still. Catacols musings to me do carry weight lookinh  at the nhp which is toying with Heighths ete. I've not checked the 10hpa at strat level, any zonal wind info but I guess a SSW is still a decent shot. What I would say is going threw January could be the best chance of something more akin to a sustained locked in cold spell. PV wise things are primed and the window of opportunity needs or hope its taken. All will be revealed in a much welcomed for me new year.

This will be the real talking point.

The length of time cold is locked in.

Well get to see first hand what a uk homegrown cold pool can do and catacol is correct. 

From now till 5th if January we have an angular momentum wane but not to very low levels. Well stay on the cold side of the jet (cold enough for snow to low levels to build up) in troughs and disturbances which we wont see until 24-48 hours on the high res models.

5th of january to middle of jan - an increase in northern blocking again due to the very big eamt on new years eve.

Middle of jan - end of february - the effects of a strato warming (which we dont fully kniw of yet but looking at trends and big hitters on twitter) a siberian express!

People need to just stay patient everything that looks like being mapped out based on the teleconnections so far have happened.

This week was always ear marked as the beginnning of the journey. Screaming cold uppers and heavy snow streamers between xmas and new year were never spoken about a building cold pool with amp waxing and waning and each wave becoming colder than the last was and tomorrow is the first day of this steady drop down in temperatures with each snow event becoming less and less marginal!

Heres to interesting times ahead!!!

[northwestsnow]

2 minutes ago, sheikhy said:

Ecm same as 12z yesterday!!gfs p and control same as yesterday!!ukmo same as 12z!!ecm mean bloody fantastic!!bring it on!!!gfs op you can go do one please!!

Quite.

Proper Winter weather incoming...

Lots of frost,fog, ice etc...

We pull in an Easterly feed on EC as we hit the weekend...

 

[Scott Ingham]

21 minutes ago, Battleground Snow said:

ECM mean at 240,

Looks very cold, low heights in the right place in France and the vortex pushed over Asia and the Pacific

 

Wow!!

[sheikhy]

Just now, northwestsnow said:

Quite.

Proper Winter weather incoming...

Lots of frost,fog, ice etc...

We pull in an Easterly feed on EC as we hit the weekend...

 

The gfs op has been an absolute waste if time last 48 hours!!had its little moment of glory but now gone back to what it does best!

[Scott Ingham]

9 minutes ago, dragan said:

Latest gfs shows as of the 4th Jan a new pattern with South Westerly winds taking over until the end of the run.

Not overly mild, but the South West and South coast would see temps nudging into double figures.

Further North, the temps fall away as you would imagine 

Which has zero support as to be expected just to point out to any newbies.

Its a rogue run

[Griff]

19 minutes ago, Weather-history said:

Here was ECM 0z from 17th December for today

GFS 0z 

GEM 0z

 

The reality

 

Hey now, no one asked for reality here

Rather, I should say, good morning and thank you, always very refreshing to be reminded

[Griff]

Just now, Scott Ingham said:

Which has zero support as to be expected just to point out to any newbies.

Its a rogue run

Means and ensembles anyone? 

I'm busy making porridge for a 4 year old... 

[Lampostwatcher]

Can't grumble at this mornings 

Charts 

A locked in 6 days at least cold spell 

Starting from later this evening 

Snow showers and more organised troughs I'd imagine 

Cropping up as the week goes ahead 

All exciting white stuff 

❄❄❄

[Scott Ingham]

10 minutes ago, fellmike said:

But which model i liable to be correct or is it guess work?

The model with most scientific support.

The ecm is backed by other models other models and the GFS is the only one showing this outcome so youd naturally put a low percentage on this happening 

[Battleground Snow]

4 minutes ago, Griff said:

Means and ensembles anyone? 

I'm busy making porridge for a 4 year old... 

GEFS for London can see the operational in green is at the top end for 850 temps, and also huge scatter towards the end.

 

Edited December 27, 2020 by Battleground Snow

[ICE COLD]

I really hope the ECM and the ens are on the money here . Can’t believe what the gfs is showing this morning , I’m in shock and the GEM . 

[Scott Ingham]

3 minutes ago, Griff said:

Means and ensembles anyone? 

I'm busy making porridge for a 4 year old... 

Someone will post them mate i havnt slept yet wait8ng for the morning runs hahaua but ecm ukmo and the gfs parallel all carried on where we left off

[IDO]

1 minute ago, Griff said:

Means and ensembles anyone? 

I'm busy making porridge for a 4 year old... 

The gfs op has circa 15% support at d10:

The wedge/easterly combo in some form or other is the main cluster. The ens are showing entropy so I would not be sure of ecm or gem (different at d5). Def more runs needed as the esb exiting HP cell at d4-5 has been a nightmare to model since it showed up!

[Scott Ingham]

1 minute ago, Battleground Snow said:

GEFS for London can see the operational in green is at the top end for 850mb temps, and also huge scatter towards the end.

 

Yeah practically an outlier

[Tim Bland]

Just now, sheikhy said:

Any fresh updates on tonights snow!!?

Looks like it’s pushed back west again to me. Also less widespread than shown last night. Good news is that more features are starting to pop up for later in the week. Below is for Tues morn then end of the week from ECM

[Scott Ingham]

15 minutes ago, sheikhy said:

Ecm same as 12z yesterday!!gfs p and control same as yesterday!!ukmo same as 12z!!ecm mean bloody fantastic!!bring it on!!!gfs op you can go do one please!!

Brilliant morning mate! All moving along nicely!

[Scott Ingham]

4 minutes ago, Tim Bland said:

Looks like it’s pushed back west again to me. Also less widespread than shown last night. Good news is that more features are starting to pop up for later in the week. Below is for Tues morn then end of the week from ECM

Shows that when you get the cold in the snow will come. Its practically not forecastable when its to do with tiny troughs and low pressures. Heavy snow showers are showing being pushed in off the north sea monday night into tuesday wouldnt be surprised to see s warning out for that if it picks up more support

[nick sussex]

The GFS needs to book into rehab ! It seems to have gone completely AWOL over the Christmas period.

If the GFS 06hrs run looks the same I’ll be shocked.

[Battleground Snow]

@Griff ECM for London,

 

[MKN]

On 25/12/2020 at 19:23, Mike Poole said:

 

Shift west on some models but not all. Latest NMM still reasonable for many areas. 

[Scott Ingham]

1 minute ago, nick sussex said:

The GFS needs to book into rehab ! It seems to have gone completely AWOL over the Christmas period.

If the GFS 06hrs run looks the same I’ll be shocked.

Agreed Nick. Its one of them rogue runs it likes to throw out.

If its to do with split energy though it wouldnt surprise me if it happened slowly with its tail betweek its legs