Model Output Discussion - Colder but how cold and for how long?

[Geordiesnow]

1 minute ago, Day 10 said:

What are you on about? I post charts many times.

My point was, what is the point in worrying about temps a week on Saturday when there is so so much uncertainty well before.

I never understand the hypocrisy where people can post about an upcoming cold spell at 192-240 hours range yet when people post charts showing a potential return to Atlantic weather, it's frowned upon.

Lots of weather to get through of course but you can't rule out the possibility as 2 different models  have picked this up now but of course a subtle change could have impacts down the line also.

[Metwatch]

19 minutes ago, Geordiesnow said:

Whilst I don't think you can rule out the Atlantic coming back in(as it's hinted at by 2 different operational models), it is quite incredible just how quickly the outlook turns, quite interesting really.

Yeah that's what is making me curious too and it's more than 1 model / set of ens showing that rapid change. I think it's that huge storm off the ESB forming on Tuesday causing even more issues than there already is. Strong heights around Alaska too leading into a cold air outbreak over the states which we have the first of early next week and so that turbocharges the jet over the Atlantic. Too far out as always but I can't ignore or discredit them either.

 

Throw in another 2 named storms as well because why wouldn't it

Edited January 11 by Metwatch

[Cuban Zebra]

Ooh GFS!!!

[Mcconnor8]

Looks like the mean 850s for the South on the 18z for mid next week would have been near the bottom of the pack on the 12z ensemble, quite a definitive shift South and prolonged colder conditions.

[Cheshire Freeze]

1 minute ago, Scott Ingham said:

 

I’ll eat my dog and I love my dog! If there isn’t a disturbance that throws up snow next week!

Your poor dog will be checking the outputs more than the snow starved members on here.

[Allseasons-Si]

Look at the mean 850's now -8 into the midlands than the borders of Scotland

we are still upgrading in this regard,...how much upgrades can we take,...all of them

[Derecho]

A note for those who are anticipating a dry and cold spell if that GFS transpired...

This was a chart from the early hours of December 2nd 2021. I was on night shift expecting clear skies for England and Wales as that is what every model had. Unexpectedly a snowy trough formed in Scotland and gave a widespread covering overnight (across quite a large area as well)

The first model to pick up on it was the ECM 18z the night before. It wasn't a pleasant night shift.

Yes cold and dry is what the models are showing but that doesn't equate to reality.

Edited January 11 by Derecho

[Ice Day]

The Control following the Op at 144

The Mean is a significant upgrade vs the 12z for the same time

 

 

That's enough from me. An excellent end of the day.

Until tomorrow, when we do it all again! 

[Mcconnor8]

Arpege 18z said you want better blocking in Greenland, sure here you go.

[Captain Shortwave]

Some very strange goings on around day 4 in the ensembles. The cause of this appears to be a shortwave appearing on the core low heights over Scandinavia that passes fairly close to the east coast of Scotland, this appears to enhance the depth of cold sweeping down the eastern side of the country.

Just posting one ensemble to show this;

Note the kink east of Scotland on here.

So lets see if any other models showed this;

ECM

It is sort of there to the north of Scotland, but it gets more absorbed into the part low. It might be worth keeping an eye on because a shallow system with embedded frigid air appears and heading close to the UK could be the surprise we were hoping for.

[Bricriu]

21 minutes ago, Mcconnor8 said:

Delayed on this run by a day, and I expect it will keep getting delayed further run by run for a while.

I pray it does. Was it back in 2013 this kept  happening on the models during a cold spell? I am nearly sure it was either 2013 or 2012.

[Scott Ingham]

5 minutes ago, Cheshire Freeze said:

Your poor dog will be checking the outputs more than the snow starved members on here.

Hahahahaha that’s hilarious

[Geordiesnow]

5 minutes ago, Metwatch said:

Yeah that's what is making me curious too and it's more than 1 model / set of ens showing that rapid change. I think it's that huge storm off the ESB forming on Tuesday causing even more issues than there already is. Strong heights around Alaska too leading into a cold air outbreak over the states which we have the first of early next week and so that turbocharges the jet over the Atlantic. Too far out as always but I can't ignore or discredit them either.

 

Throw in another 2 named storms as well because why not, drunk pub run

And like how we seen charts go from zonal to blocked fairly quickly, it of course can do the same in reverse but at least all that stuff is well past the medium term, it's the cold stuff first and for some some snowy weather.

And yes the upgrades to the initial northerly is pleasing, makes a nice change really, hopefully any milder sector can be squeezed out before a potential reload. For Scotland from what I'm seeing, the cold arrives on Saturday and looks more or less guaranteed for at least 5 days. The window for beefy convective snow showers in northern and eastern Scotland has also improved for Sunday daytime into Monday so could be some quite deep snow here by Monday night.

 

[Allseasons-Si]

That mean is,...i mean is a beauty

my local and London flatlining below the -5 isotherm,...take note,...this is coming to a place near you.

Edited January 11 by Allseasons-Si

[Frigid]

GEFS 18Z.. wow.

The almighty -10C isotherm. Look how the OP and Control follow the mean. Can't get any more support within an ensemble pack if you want. 

Edited January 11 by Frigid

[birdman]

10 minutes ago, Cuban Zebra said:

Ooh GFS!!!

"Monsieur, with these Charts you're really spoiling us!"

[Geordiesnow]

4 minutes ago, Captain Shortwave said:

Some very strange goings on around day 4 in the ensembles. The cause of this appears to be a shortwave appearing on the core low heights over Scandinavia that passes fairly close to the east coast of Scotland, this appears to enhance the depth of cold sweeping down the eastern side of the country.

Just posting one ensemble to show this;

Note the kink east of Scotland on here.

So lets see if any other models showed this;

ECM

It is sort of there to the north of Scotland, but it gets more absorbed into the part low. It might be worth keeping an eye on because a shallow system with embedded frigid air appears and heading close to the UK could be the surprise we were hoping for.

I think the GFS sort of has it there also but fizzles so definately one to keep an eye on. Whilst it may develop slightly less cold air around it but because it comes from a cold source and thicknesses are low, it shouldn't be marginal. 

[Kentish Snowman in Yorks]

6 minutes ago, Captain Shortwave said:

Some very strange goings on around day 4 in the ensembles. The cause of this appears to be a shortwave appearing on the core low heights over Scandinavia that passes fairly close to the east coast of Scotland, this appears to enhance the depth of cold sweeping down the eastern side of the country.

Just posting one ensemble to show this;

Note the kink east of Scotland on here.

So lets see if any other models showed this;

ECM

It is sort of there to the north of Scotland, but it gets more absorbed into the part low. It might be worth keeping an eye on because a shallow system with embedded frigid air appears and heading close to the UK could be the surprise we were hoping for.

Surely potential for lows of the polar variety to form in a flow that cold?   

[Man With Beard]

30 minutes ago, Tim Bland said:

Warm up by the weekend still there …

That's actually been very consistently modelled aside just a few runs. Actually, the whole thing has been modelled fairly consistently by the ensembles. There never was the promise of more than a few days of cold IMO.

[Met4Cast]

If the models aren't getting blocking right at days 3/4, why do people expect them to be right at days 9/10? 

[MJB]

One thing is for sure with the 18z, it brings many snow opportunities to the N of the Midlands

[Scott Ingham]

Just now, Met4Cast said:

If the models aren't getting blocking right at days 3/4, why do people expect them to be right at days 9/10? 

What’s been shown is the means are king! 

They have been rock solid in the face of some odd runs, shortwaves, bulges in the ops. But the closer we have got the more the ops have firmed up on what was showing 10 days ago!

 

This cold spell has some legs to go yet! 
 

1-0 GDSM on this years chases!

[Spah1]

18 minutes ago, Derecho said:

A note for those who are anticipating a dry and cold spell if that GFS transpired...

This was a chart from the early hours of December 2nd 2021. I was on night shift expecting clear skies for England and Wales as that is what every model had. Unexpectedly a snowy trough formed in Scotland and gave a widespread covering overnight (across quite a large area as well)

The first model to pick up on it was the ECM 18z the night before. It wasn't a pleasant night shift.

Yes cold and dry is what the models are showing but that doesn't equate to reality.

Cold and dry? Rubbish

[SussexSnow]

Crazy cold on the ensemble by the 16th. Average 850hpa temp is -8.9c and some go as low as -14c.

Edited January 11 by SussexSnow

[Allseasons-Si]

If London is good below the -5 line,then all is good

good night guys