Model Output Discussion. 3/12/2022. How cold will it get?

[chionomaniac]

New thread here. Hopefully this will be the best cold spell for years. But what will the models forecast? Discuss. 

[Eagle Eye]

Lots and lots of pages that I don't have the time to catch up with but its clear that excitements building and why not?

In hindsight 

+VE AAM, MJO phases 6/7 causing -VE NAO due to Greenland blocking (not to mention significantly -VE AO) andmost runs now showing a non west based -NAO and you'll have wondered why so many prams lost toys but that's the joy of the model thread, sometimes the pendulum actually swing towards the way of the coldies as we get closer and sometimes the pendulum swings towards the milder solution. Let's see how this pendulum eventually swings on this one.

[Robbie Garrett]

I think the models are struggling post 120hrs+   - I suspect the low as people are already mentioning won't be as strong nor will it blast towards us.  I suspect it will get stuck like a similar scenario that happened on 20-24th Nov 2010 (When the MetOffice started talking of a breakdown).   NOAA was talking about a 3 out of 5 confidence with the strength of this sub-tropical/tropical low.

 

There was a barrage of low's against the Greeny block.

 

They all got stuck over New England.

 

With the odd low heading south of the Greeny block.

6 hours ago, Howie said:

Am I the only one that thinks this new low to the south west is being way over done? How could it possibly become that intense, basically a hurricane in the northern Atlantic in December? Just seems wrong to me

5 hours ago, chionomaniac said:

Passion. It takes a bit of self control to step back and look at the bigger picture. Just stick to day5-6 and past that just for fun. 

In 2010, the models constantly showed the end of the cold spell, but this was put back time and time again. With this being a strong split into the lower Strat, rather than a transient Greenland High, I suspect the same will happen again. 

4 hours ago, Notty said:

and NOAA are not expecting any tropical storms there in the next five days and a storm like that would already be brewing and monitored by the NHC (in my opinion)

(Cross posted)

 

1 hour ago, clark3r said:

I am starting to believe that I will get my snow cover for the first time since 2010. Excited by charts, it is def coming home England

It would be absolutely hilarious if England did win, that the victory parade was cancelled by Sadiq Khan due to heavy snow fall. (Another Crisis).

Edited December 3, 2022 by Robbie Garrett

[Derecho]

One thing to look out for in the next couple of runs. The 12z gfs control had this secondary northerly with very cold uppers into Scandi shortly after ours. This is key to something very cold further down the line. Watch out for this.

Edited December 3, 2022 by Quicksilver1989

[Catacol]

Well - lookie here. Thought I’d do a little check of the angular momentum context and got a bit of a surprise

Torque has rebounded pretty quick from the sharp drop earlier this week with a notable climb coming out of the Himalayas. 

And relative calculated momentum is back above 0. I appreciate this is probably gobbledygook to some….but to put all this into a nutshell - the drop in momentum that signalled a possible beginning to a Nina forcing within the atmosphere has lasted very little time indeed before rebounding back to a position that will preserve a more Nino shape to things. And the context there is that a Nino pattern is much more conducive to downstream amplification from the Pacific rather than the flatter Atlantic pattern usually produced by a Nina response and low momentum. So…. with the MJO predicted by many to emerge with some strength mid month there is every reason to expect renewed amplification. Given our block looks quite long lived in any case this means a teleconnection context that is not suggestive of a collapsing block and Atlantic inroads. Always a bit of luck needed to get amplified patterns in the right place - but with cold air already in place there is every reason to have some confidence in the cold spell going long.

Every satsuma coming out of the Xmas fruit bowl is tasting pretty damned sweet at the moment.

Edited December 3, 2022 by Catacol

[BlueHedgehog074]

A little focus on the current chart from the 12Z GFS at 00 hours, it is quite incredible the ribbon of High Pressure that is occurring to the North-West, North and North-East of the UK. A lot of blocking. Not bad going at all for the beginning part of December. Don’t see this sort of thing often!

[Rayth]

Well the Americans are getting excited , shame it’s behind a paywall , ‘an unusual climate phenomenon’  

 

 

[Mark wheeler]

3 minutes ago, Rayth said:

Well the Americans are getting excited , shame it’s behind a paywall , ‘an unusual climate phenomenon’  

 

 

I believe @Allseasons-siposted earlier about why they may be a tad excited. 

[Allseasons-Si]

My long post has just gone missing

[sheikhy]

Gfs 18z cold air incoming at 72 hours!!yes 3 days thats 3 days away!!!!

[CSC]

GFS pub run is going to be a cracker.. Blocking established at just day 3. I reckon this could show some singificant precip. Lets wait..!

[CSC]

 

Just look at the difference already between yesterday's 18z and today's - at approx t90 hours. A far more established block on this evenings run. This is what we want!

Edited December 3, 2022 by CSC

[Mike Poole]

GFS T96 v 12z T102:

Low to NE hanging by a thicker thread than on the 12z.  Let’s see what happens with this one…

[Snowman.]

2 minutes ago, Mike Poole said:

GFS T96 v 12z T102:

Low to NE hanging by a thicker thread than on the 12z.  Let’s see what happens with this one…

Looks like it may even drop down..

[Captain Shortwave]

So with the cold upon us, the snow….

 
 

Secondary low with a cold core. Polar low territory here. Associated with this is a band of heavy snow that is forecast to move south. There is already a warning out for this across the north of Scotland.

As for the main run, the GFS has a stronger link to the Asian vortex segment.

Edited December 3, 2022 by Captain Shortwave

[Allseasons-Si]

Long story short

the NOAA has a link up of Greeny/Scandi +ve heights,...+ve heights dropping slightly further south on the 8-14 dayer

ECM control has a runner low at day ten,snow on the leading edge with strong easterly winds with blizzards backing northerly after

more E/NE winds starting to show on the probability around mid month on De-built

and finally the ICON has that blue heart again, i want an ace on the gfs 18z please

i cannot believe that my post went earlier,i know why now, @chionomaniac closed the thread down,...never mind

a shiny new thread it is then,just in time for a Dec to remember

 

 

[lamppost watcher]

GFS should be a beauty!

[Johnp]

Just now, lamppost watcher said:

GFS should be a beauty!

I just don’t understand why the trough doesn’t get pushed southwards by the HP to the north?

[Mike Poole]

5 minutes ago, Snowman. said:

Looks like it may even drop down..

Well it hasn’t done at T120:

Edit, and remains firmly attached at T132 - should go well this, now:

Edited December 3, 2022 by Mike Poole

[MATTWOLVES 3]

So it's get the Block in place...check

The cold will follow...check.

Then the snow will gather! Check and check mate.

[Allseasons-Si]

This is lovely at 126 and has a resemblance of one of these...

[sheikhy]

This gfs moves towards ecm at 144 hours in keeping a long north east flow all the way russia!!no ridge break on this run!!

[Johnp]

The winter hurricane is back again. Think we have to assume this is going to happen now - just what happens to it is the question. I would expect it to shear with energy splitting north westwards and south eastwards. 

[Eagle Eye]

I'm not going to say much other than a brilliant GFSrun, I'll let others talkore about it, I'm the teleconnections amateur, you lot are the GFS professionals.

[Met4Cast]

The GFS has been performing terribly of late coming in 4th place behind ECM, UKMO & GEM. 

At least the 18z seems consistent with the 12z, that's more than we've been able to say for a while.