Model Output Discussion - Colder spell ending, what's to follow?

[mountain shadow]

3 minutes ago, Steve Murr said:

Very positive UKMO tonight > 144 shows the -AO tanking, deep cold filtering out of the pole.

All of the UK cold spells have come 3-5 days after this..

The run into xmas is looking exciting-

What's the chances of getting the ridge into Greenland and driving the trough East to do you think?

Edited December 9, 2020 by mountain shadow

[SMU]

The low will slowley shear apart so energy going east & West...

GFS at 144 similar & svalbard deep cold alligned much better - could be close this run

[frosty ground]

These secondary lows could be ones to watch, rain makers and potential for strong wind

[Day 10]

6z GFS

12z GFS (pattern ever so slowly getting squished south)

[IDO]

When we got better WAA in the Atlantic it was due to the spoiler low moving N/NE on the vortex. Now it is riding the jet chasing down the mini-ridge and this phasing seems a lost cause now:

So part 2, can we get the Arctic high to sink to our side of the NH?

Whether that helps or not as there is bound to be something that scuppers that, it would be nice to see where it takes us?

[Eskimo]

That is one beautiful NH profile. Second image is 2015 when we had that dreadful december. 

[mountain shadow]

That is one impressive Arctic High and pushing our side of the hemisphere..

[Daniel*]

I can discern a difference here in Arctic :) 

[DavidS]

It feels like it’s there for the taking, that euro high just needs to politely shove off.

[Howie]

1 minute ago, DavidS said:

It feels like it’s there for the taking, that euro high just needs to politely shove off.

I really hope it does, it's the only thing preventing us from having a good cold spell. It's crazy how it was absent the whole time until now

[Eskimo]

Other than everything being slightly further south, the GFS at +210h looks remarkably similar to the 06z for our part of the world. Never thought I'd see the day where the GFS becomes...consistent.  
 

[Eagle Eye]

Certainlu getting some deep lows on these models. GFS is positive for this winter, always has been. 

2oc seems to be the big low, dips elsewhere maybe. 

Ecmwf on it's own laughing at how funny it is that people believe it. 

[mountain shadow]

If the Atlantic low moves 500 miles East, we're in. Painfully slow though.

[IDO]

That euro high is basically an extension of the block to the east (Russian high) which prevents a trough dropping anywhere downstream. Without those blocks, the trough would fall, and the Arctic high would build and stretch towards Greenland. With the status quo, the Arctic high will meander around the pole and direct the traffic orderly and flat waiting that Pacific wave from the mjo signal! A holding pattern it seems...

d10>> 

[Daniel*]

I’ve been viewing GEFS members and there has been a growing trend for those brutally cold uppers to fall into northern Scandi, while it may not be immediately viable good to see deep cold not a million miles away. 

[Day 10]

Just waiting for the damn to burst above our heads.

[mountain shadow]

Big kick East, come on..

[Eskimo]

7 minutes ago, mountain shadow said:

If the Atlantic low moves 500 miles East, we're in. Painfully slow though.

Slow and steady wins the race...unless of course you're talking about climatology, in which case it might not. 

[ITSY]

Don't get me wrong, I'd hate to be stuck in a fluid and mild zonal pattern, but wow oh wow is this a tedious holding pattern. Everything moving at a snails pace thanks to that eurasian high... 

The question here is can we get that advection northwards out of the Atlantic/Eastern US seaboard. Scandi is certainly priming itself for a southward cold push if we can get the building blocks in place - note a very similar area of advection that didn't come off at the same time in the 06z run...something to watch both in the next 10 mins and over coming runs...

 

Edit: steady as she goes here

Some encouraging signs: 

1) Arctic High back and pushing south
2) Atlantic block pushing north 
3) Hudson lows retreating back westward - a must to avoid our high being blown away 
4) Lower heights edging, inch by inch, into Europe 

We need all these things to happen at the very least to be successful in this bite of the cherry
 

Edited December 9, 2020 by ITSY

[swfc]

6 minutes ago, IDO said:

That euro high is basically an extension of the block to the east (Russian high) which prevents a trough dropping anywhere downstream. Without those blocks, the trough would fall, and the Arctic high would build and stretch towards Greenland. With the status quo, the Arctic high will meander around the pole and direct the traffic orderly and flat waiting that Pacific wave from the mjo signal! A holding pattern it seems...

d10>> 

Indeed. The slight ridging from the south has scuppered things also. Big improvement tho

[TSNWK]

 so so so very close.. around 240..  come on!...... 

[IDO]

2 minutes ago, swfc said:

Indeed. The slight ridging from the south has scuppered things also. Big improvement tho

Yes, hate to use the over-used "potential" but compare the current upper-air NH profile to forecast:

The Arctic high has done its job to dissipate that cold to lower latitudes and just a gentle push here and there from ridges would see the fun and games start!

[swfc]

1 minute ago, TSNWK said:

 so so so very close.. around 240..  come on!...... 

Low going up west coast of UK at 270

[alexisj9]

1 hour ago, Steve Murr said:

Updated ICON 12Z 120 > twin blocks over the pole forcing the PV to drain in the mid lats > troughing alligned favourably over svalbard > nothing like the last 10 years in Dec

Fingers crossed, again this is what I expect the next move to look like, but more runs are moving away from than to this at the min. I hope more twelve z output favours this. I did not like GFS last two runs at all, but have to remember it can be over progressive, when it comes to Atlantic lows.

[frosty ground]

 

First sign of the jet streaking up the west side of Greenland, if we can get it to swing round it will bring the cold air with it,