Model thread discussion - cold spell looming

[sheikhy]

2 minutes ago, Don said:

Yes, I've just edited my post after looking at the chart again.

Any update on the ecm mean charts between 120 and 240 hours?!!

[Don]

Just now, sheikhy said:

Any update on the ecm mean charts between 120 and 240 hours?!!

Not sure.

[feb1991blizzard]

1 minute ago, bluearmy said:

Clear where eps see the favoured spot for the upper ridge to sit - that’s gonna place the cold flow to the se of that 

Needs to gain latitude to advect cold our way rather than sending it into Europe, looks to me like the cold initially missing us to the SE, all the output points to me that it will take another bite of the cherry, can it ultimately become griceland, clusters maybe more instructive.

[matty40s]

13 minutes ago, BlackburnChris said:

If you look at Iceland between +192 and +240 it is also retrogressing West ....

Should trigger plenty of volcanic activity and movement of the tectonic plates, triggering a volcanic ash winter then.

[DOdo]

My Tuppence Bet is on that Low stalling off the Southwest of Ireland and not proceeding  any further. Met Eireann this evening are unsure as how things will progress after wednesday,  Anyway  It is  almost a week away, anything can happen. There will be a few more wobbles in the mix. no doubt. exciting times ahead

[phil nw.]

Tbh none of the mean day 10 charts take the high far enough north to return cold uppers from the east.Gefs is the best of the 3 and they all do keep the surface cold to that point.

It doesn't break the pattern completely and there is still cold upper air to tap into further east but to get it here we need that high much further north-the gem op at t240 for example would be close to another easterly.

There are differences within the mean charts as can be seen indicating the uncertainty wrt amount of amplification so further changes will likely occur.

In the meantime the cold easterly is entering stage right with a very wintery week to come.

 

Edited February 6, 2021 by phil nw.

[nick sussex]

In the UK the hardest part is not seeing a Scandi high set up, but whether that  can align sufficiently north and can direct the cold sw .

Even though the UKMO isn’t quite there at day 6 , it has the cold pool further north and the alignment is the best out of the big 4 models .

 

 

[Lukesluckybunch]

11 minutes ago, nick sussex said:

Big hitter ! Lol nice of you to say that but others have  more technical knowledge. I’m the meat and two veg , no frills generally but try my best to give an impartial view even though I’m a hardened coldie ! 

In terms of the cold spell, yes the trend is now to extend the cold as the high to the ne is putting up a good fight .

The bigger uncertainty is whether the UK can tap into that amazing deep cold pool to the east .

As long as you keep a flow off the continent even if the upper air temps relax the surface will still be cold . 

So some severe night time frosts especially over snow cover .

I think we need a few more runs to see whether the models are going to go for a quicker attempt to bring in that cold pool , or whether they take the longer attempt . This is by no means guaranteed to land though , but I certainly hope it does ! 

Haha ok then.yes it would be good to see that cold pool move West towards us,we are in with a shout at least.I think the least we are looking at is what the ECM showed earlier even that is cold if not very cold throughout albeit a little boring.but yes lots of potential out there going forward

[SqueakheartLW]

Time for my 12z model update on the end of the cold spell and the peak of the milder spell. After the watering down of the milder spell on the 06z GFS I hope for more of the same here with 12z. Also can both GEM and GFS push the end of the cold spell back even further. Lets take a look

12z GFS

The end of the cold spell on the 12z GFS comes in at 144 hours away. This compares with 156 hours away on the 06z. Taking into account the 6 hour difference of the run this is a big X for the GFS 12z as it has brought the end of the cold spell forwards by 6 hours.

What it has done like it did in the 06z was to place an average Scandi high to our east again, tick. This should help to fend off any attack from the Atlantic at least. The anomaly chart shows the S and W milder with the N and E colder. This could end up a battleground instead of a transitional event which could be a real snow maker for some, tick.

The peak of the milder spell on 12z GFS come in at 174 hours away, this compares with 228 hours on the 06z so taking account of the time difference between the runs this is also bad news as the mild peak is closer by 48 hours compared with the 06z, a big X here GFS 12z

The pressure chart also makes interesting viewing too and that Scandi high is still there. It appears that the high fended off the mildest air as the anomaly chart shows that areas in the far east of the UK are average at best and slightly below in some locations, tick. Also the mild peak has been watered down yet again compared with the 06z. On the 06z it was -1.8 at 850hpa. Now on the 12z it is -2.2, big tick GFS 12z

12z GEM

How does the GEM stack up against the GFS and its own 00z run too. The end of the cold spell on the 12z GEM comes at 162 hours away. This compares with 162 hours away also on the 00z. Taking into account the 12 hour difference in the run times this means a 12 hour extension to the cold spell, tick tick GEM 12z

The peak of the milder spell comes in at 252 hours away compared with 228 hours away on the 00z. Taking into account the 12 hour difference between the runs this has pushed the mild peak back quite a bit by a nice 36 hours. Big tick GEM and ticks all around for the GEM overall then.

Some nice fantasy cold charts from both 12z GFS and 12z GEM

GFS 12z Member 21     +234 hours     850hpa temp -17.9

GFS 12z Member 22     +240 hours     850hpa temp -16.5

GFS 12z Member 9     +252 hours     850hpa temp -16.7

GFS 12z Member 19     +216 hours     850hpa temp -13.2

GFS 12z Member 25     +282 hours     850hpa temp -12.3

GFS 12z Member 24     +342 hours     850hpa temp -17.9

GEM 12z Member 9     +294 hours     850hpa temp -16.7

[Jason M]

5 minutes ago, nick sussex said:

In the UK the hardest part is not seeing a Scandi high set up, but whether that  can align sufficiently north and can direct the cold sw .

Even though the UKMO isn’t quite there at day 6 , it has the cold pool further north and the alignment is the best out of the big 4 models .

 

 

Problem with this one is actually that the pressure is so high it will kill and prospects of precipitation stone dead. Its like the models got the idea of a Scandi High and dialed it up to 15! One of those occasions where everyone expects convection due to cold uppers and we end up with 5 days of stratus!! Could do with the high a bit further north as much as anything to drop the pressure below 1025pha across the UK.

 

 

[FreezingFog]

1 hour ago, Notty said:

Freezing fog and hoar frost for you I imagine

I'm here, where's hoar frost

[nick sussex]

4 minutes ago, Jason M said:

Problem with this one is actually that the pressure is so high it will kill and prospects of precipitation stone dead. Its like the models got the idea of a Scandi High and dialed it up to 15! One of those occasions where everyone expects convection due to cold uppers and we end up with 5 days of stratus!! Could do with the high a bit further north as much as anything to drop the pressure below 1025pha across the UK.

 

 

The orientation and lack of elevation of the high is the main issue and the flow is mainly se later in the week so that limits that , notwithstanding the upper cold relaxes. Maybe the models want to give coldies a breather after all the recent drama and want to go the longer route ! I think we’ll know by tomorrow evening whether the models want to go for an earlier attempt, because day 6 into 7 is where some changes could bring that into view .

[Windysun1]

8 minutes ago, nick sussex said:

The orientation and lack of elevation of the high is the main issue and the flow is mainly se later in the week so that limits that , notwithstanding the upper cold relaxes. Maybe the models want to give coldies a breather after all the recent drama and want to go the longer route ! I think we’ll know by tomorrow evening whether the models want to go for an earlier attempt, because day 6 into 7 is where some changes could bring that into view .

What is required is a low in Italy to prop the high pressure over Europe and the cold would divert west. Im not saying that will or wont happen this far out but anything is possible.

[SqueakheartLW]

Just had a look at this on weather is cool

The atmosphere is in total chaos. Look at all those easterly average winds in the troposphere for the entirety of the chart from left to right. Don't think I've ever seen one of these with such a prolonged period of average easterlies at 60N

As for the stratosphere it seems we have resumed the disconnect between the stratosphere and troposphere again. Winds have predicted to go way above average at 1hpa but down at 10hpa we only just scrape average by the end of the run. As for the rest of the stratosphere below 10hpa we remain below average throughout

[SnowBlake]

Don't forget the live wind direction/speed map here!

earth :: a global map of wind, weather, and ocean conditions

EARTH.NULLSCHOOL.NET

---

See current wind, weather, ocean, and pollution conditions, as forecast by supercomputers, on an interactive animated map. Updated every three hours.

Even over the far SE it is now NErly wind. Just waiting for the cold to start closing in which is probably over Belgium.

Good luck all, from a snow covered Latvia ❄

[rdt123]

Looks like around 50/50 spit in the models between the return to something less harsh or the potential for something even harsher. Was surprised to see the high sink on the ecm. Really fascinating at the minute

 

 

Edited February 6, 2021 by phil nw.
off topic content removed

[Frigid]

JFF but P24 is what we want! Proper scandi high and 850s below -15 for much of England

    

[Decemberof2010]

Just checked the GEFS. There's some stonkers in there. Could we really land something along these lines?

Brutal cold

 

[Chesil View]

A bit late checking the charts this evening interesting that the ECM at 240 shows early stages of retrogression towards the Griceland region that would certainly open the floodgates to deep cold Round 2.

Edited February 6, 2021 by Broadmayne blizzard

[frosty ground]

Gonna be a tightening of the isobars 

[Premiere Neige]

25 minutes ago, Broadmayne blizzard said:

A bit late checking the charts this evening interesting that the ECM at 240 shows early stages of retrogression towards the Graceland region that would certainly open the floodgates to deep cold Round 2.

Leave Elvis out of this!!

[Malarky]

Dead in here! Thoughts on the pub?

[loafer]

1 minute ago, Malarky said:

Dead in here! Thoughts on the pub?

With apologies to the mods...

[Scott Ingham]

Just now, Malarky said:

Dead in here! Thoughts on the pub?

Very 2019 after being a traditional escape for many after a hard weeks work. Rumoured to be making an appearence in April 21 and something im personally very fond of

[Captain Shortwave]

Another tweak towards the ECM in the earlier stages.

Wind veering more to the north east and drawing in the -12C isotherm more extensively for a time. This could provide more showers for a larger proportion of central and eastern England.