Model Output Discussion - Staying cold into the new year

[kold weather]

Some great morning runs from the operationals. Cold getting really established upstream and here.

Still need a huge word of caution though, any setup where we have a dropping LP is at *huge* risk of being either too strong or too far west. If either happens it will basically be a rerun of this week where good synoptics, bad uppers and we will be depending on exact air flows.

The 00z runs are threading a fine line. They are however almost perfect if your looking for countrywide snow opportunity.

[Griff]

1 hour ago, That ECM said:

T144 all 3. Fascinating but not as fascinating as watching and reading in here. 

 

Go back a couple of months  and think of any of these as the starting point. Genuinely from coldies POV who would have said no thanks?

Well this to me is the news story of the morning!

Hopefully like the models we can all agree on that... 

The GFSP does too. 

As does the GEM. 

 

[Penrith Snow]

Like this week I think next weeks easterly will be more wintry than what is being modelled. Nothing widespread but snow is likely over modest high ground particularly in the west ironically furthest from the east coast. After that the ‘potential’ is obvious, it might come to little or nothing but a spell of severe weather in the second half of January is now a real possibility. Interesting that this week some of the snowiest parts of the UK have been the North West which often miss out. With snow you just don’t know what’s going to happen until T-0.

[Frosty.]

Just what is it about the ECM and day 10??...anyway, who cares, it knocks it out of the park again!...lovely stuff..long may it continue!  

 

[Chesil View]

16 minutes ago, Penrith Snow said:

.Dear me, that is a good old fashion 1960’s chart with the easterly air now sourced over Russia rather than the eastern Med. stunning output really

I was just thinking the same thing. PS.

Best ECM run so far this winter with that milder eastern med sourced air being pushed further east with each frame.

[syed2878]

30 minutes ago, Scott Ingham said:

A warming is already nailed on. It starts on the 5th as has been mentioned a few times. Its just this type of warming is a displacement warming.

There are signs of a split warming to follow they are all the same thing

 question guys according to some tweet that the SSW is already taking place is this not true and is the warming still to come yet in January? not bad I put today GFS and ECM looking cold 10 days away though. May I wish everyone here at net whether a very happy and a prosperous 2021 after a very very difficult year for all of us let’s hope 2021 is going to be a good one for all of us. happy Cold and a snowy new year everyone.

[Scott Ingham]

1 minute ago, syed2878 said:

 question guys according to some tweet that the SSW is already taking place is this not true and is the warming still to come yet in January? not bad I put today GFS and ECM looking cold 10 days away though. May I wish everyone here at net whether a very happy and a prosperous 2021 after a very very difficult year for all of us let’s hope 2021 is going to be a good one for all of us. happy Cold and a snowy new year everyone.

Its in the process right now but until winds reverse its not a ssw. They dont reverse till the 5th. The warming is happening now but it has to reach wind reversal to effect us properly. This is the 5th. 

The effects wont be felt until the middle to end of january onwards. What we see now is forcing from AAM caused by a large EAMT.

Lots to be excited about

[Tim Bland]

A good UKMO for the easterly next week. Uppers -8c and air sourced more north of east 

[bluearmy]

2 minutes ago, syed2878 said:

 question guys according to some tweet that the SSW is already taking place is this not true and is the warming still to come yet in January? not bad I put today GFS and ECM looking cold 10 days away though. May I wish everyone here at net whether a very happy and a prosperous 2021 after a very very difficult year for all of us let’s hope 2021 is going to be a good one for all of us. happy Cold and a snowy new year everyone.

The warming of the strat has begun at the very top 

it gathers pace next few days and becomes a tech SSW when the winds reverse at 10hpa/60N.  Beyond that we expect the reversal in flow to continue down into the trop which will sustain an ever stronger neg AO. ( we’ve had a neg AO for some time anyway)

how the bits fall into place in the NH pattern for nw Europe remains unknown .....

[sebastiaan1973]

30 minutes ago, Scott Ingham said:

No worries if anything it gets you excited at the fact were producing these charts before a ssw! Imagine that day 10 chart then as reverse zonality kicks in the vortex from russia starts heading our way!! Its entirely possible!

I assume  you saw this chart. With a displacement of the vortex in the Atlantic Oean. Doesn't seem to mee a good development.

[Duane S.]

This sort of abnormal winter northern hemispheric set up is what excites me more than getting snow on the ground I think! Maybe because living where I do tempers snowy expectations somewhat. Several consecutive years without a flake falling is not unheard of down here. 

The NH view is truly incredible right now. Combine with the soon to be SSW and likely further warmings and vortex upsets, and the potential is about as good as it gets. I know some hate the word ‘potential’ but, like it or not, without potential, you get nothing. 

Times like this are rare for us cold weather nutters, and it’s for these moments that I’ve spent so much time pouring over charts and data every winter for 20+ years. This is not normal folks, just try and enjoy the ride. 

This could be a massive letdown with the weather we end up getting on the ground, but IMO we’d have been very unlucky if so. On the flip side, this could end up being an historic winter.

This ECM this morning chart gives me goosebumps...

[tinybill]

eastly next week snow showers  what can mess it up now!!!

[Scott Ingham]

1 minute ago, sebastiaan1973 said:

I assume  you saw this chart. With a displacement of the vortex in the Atlantic Oean. Doesn't seem to mee a good development.

No the strat isnt really my thing i only know the basics. Ill wait to see what chio, blue and catacol make of it

[Johnp]

1 hour ago, cyclonic happiness said:

Considering the outlook, (which is stunning compared to last year) I can't understand why there is a lack of interest this morning?

Everything is still very much in place for a good cold spell, the snow detail is a sticking point, but when isn't it?

It's a new year tomorrow and we should all go into it trying to be optimistic and forward looking....let's forget this awful year and make the best of what we have

 

Happy New Year Netweather 

I'm waiting for the nod from bluearmy before I get excited about snow in the south east!  

[kumquat]

Relative consensus across models to 144. Cold and getting colder.. Plenty of charts posted already to highlight this.

Whether it become too West based eventually with potentially milder s/westerlies or stupidly cold with the vortex dropping towards us from the NE depending on how the HP above us develops is anyone's guess this far out. Either way, what's beyond 144 is up for grabs, and I'd take what's coming for snow chances countrywide in a heartbeat.

[Jeremy Shockey]

ECM 0z ensemble mean

A great improvement on the ensemble mean from 4th to 10th of Jan which suggests that the cold spell is extended and indeed deepens.

 

[Blessed Weather]

5 minutes ago, syed2878 said:

 question guys according to some tweet that the SSW is already taking place is this not true and is the warming still to come yet in January? not bad I put today GFS and ECM looking cold 10 days away though. May I wish everyone here at net whether a very happy and a prosperous 2021 after a very very difficult year for all of us let’s hope 2021 is going to be a good one for all of us. happy Cold and a snowy new year everyone.

Here's the latest forecast charts from Berlin University for both temperatures and zonal winds 30th Dec. SSW's are declared according to what is happening with zonal winds at 10hPa 60N. You will see from the forecasts (black line) that temperature has already been rapidly climbing, causing the zonal winds to consequently plummet below zero into negative territory (which means winds switch from westerly to easterly) - that's the SSW taking place. Looking like a few days yet for winds to reverse:

Temps:  Winds:

Source: https://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

[bluearmy]

9 minutes ago, sebastiaan1973 said:

I assume  you saw this chart. With a displacement of the vortex in the Atlantic Oean. Doesn't seem to mee a good development.

At day 10, yes it’s not the best place but I doubt it will stick around there with the ridge putting further pressure on the stretched vortex. The gefs should become a better tool over the next 48 hours to asses what’s likely now that they are able to see the onset of the warming at the top of the model more clearly with their starting data. 
 

Even if we do end up with an Atlantic vortex remnant, it could be that the polar high suppresses the stretched vortex ever south and that further down in the trop we see the Atlantic lows continuing to run into Iberia 

[sebastiaan1973]

Okay, thanks for your answer

[kold weather]

15 minutes ago, sebastiaan1973 said:

I assume  you saw this chart. With a displacement of the vortex in the Atlantic Oean. Doesn't seem to mee a good development.

It's a pattern fraught with risks. Ensembles show that nicely,plenty of them either develop lower pressure in situ near Greenland with forces it to topple or they develop more of a UK upper low (so basically a rerun of the last 3-5 days weather wise) which gets absorbed into a broader Atlantic feature eventually.

If such a pattern develops we will be threading the eye of a needle, and this far out it's just too early to have any confidence, especially with ensembles being all over the place.

[Chesil View]

13 minutes ago, s4lancia said:

This sort of abnormal winter northern hemispheric set up is what excites me more than getting snow on the ground I think! Maybe because living where I do tempers snowy expectations somewhat. Several consecutive years without a flake falling is not unheard of down here. 

The NH view is truly incredible right now. Combine with the soon to be SSW and likely further warmings and vortex upsets, and the potential is about as good as it gets. I know some hate the word ‘potential’ but, like it or not, without potential, you get nothing. 

Times like this are rare for us cold weather nutters, and it’s for these moments that I’ve spent so much time pouring over charts and data every winter for 20+ years. This is not normal folks, just try and enjoy the ride. 

This could be a massive letdown with the weather we end up getting on the ground, but IMO we’d have been very unlucky if so. On the flip side, this could end up being an historic winter.

This ECM this morning chart gives me goosebumps...

Quite so my fellow South Dorset coldie. Our location always tempers our expectations but like you I get tremendous excitement from these charts too. The direction of travel is assured it's just a case of how cold and how much snow and where it falls.

[fromey]

The only way is down!

[Harsh Climate]

Here's my ratings of this mornings run in terms of snow chances and potential:

 

ECM - 9/10 Bitterly cold north easterly incoming.

GEM - 8.5/10 - North easterly incoming

UKMO - 8.5/10 - Looks primed at 144h for great retrogression of high to greenland and low plunging south pulling in north easterlies, shame run doesn't go any further.

GFS control run - 7/10 - Upto 264h pretty decent synoptically 

GFS essembles - 7.75/10 - Good cluster below -5 850 hpa until around 7/12 then after that FI but still with a good amount of members around -5, signs of long sustained cold.

ICON - 6/10 - Looks not so great with a slight warm up but it does look like the cold just about to hang in and more retrogression on the way.

 

All in all delighted with this mornings output. Great long term but like others have alluded would just like

*Deeper cold pooling into europe/russia/scandinavia.

*Uppers of -7/8 when sun-tue easterly packs the showers in.  

 

[Lampostwatcher]

Fantastic charts this morning 

Snow opportunities as we head into 

The new year and beyond 

❄❄❄❄❄❄❄

[bluearmy]

52 minutes ago, Johnp said:

I'm waiting for the nod from bluearmy before I get excited about snow in the south east!  

Haha!  Still nowt but rain from the easterly and the system working in from the continent still has Dp’s just too high but closer than we were on yesterday’s run and the west side of the low could throw up some snowy surprises into the western Home Counties and central southern England.  Of course the op development post day 7 is perfect to change the wet to white ....

the Ukmo remains progressive re lower uppers and if that’s more correct than ecm then things will change on the predicted situation ..... but the two models diverge by day 6 in any case 

Edited December 31, 2020 by bluearmy