Model discussion: Hunt for cold - into mid-January

[tight isobar]

2 minutes ago, blizzard81 said:

They look like a very decent set of ensembles from the GFS. 

The definatly are- I failed to check them earlier.. but it’s clear to see we are getting a clear path through the gfs and it’s supported! The mean and a whole lot more members going into the cold camp.. are we on the borderline of flip????

[tight isobar]

With such ens @ gfs you really shouldn’t be discounting it- it’s staying solid on its evolution- and is gaining more and more support in its operational

[BLAST FROM THE PAST]

7 minutes ago, Mike Poole said:

ECM T240:

I don’t think this chart is likely to verify at all, but if it did, the only option for the high is to retrogress, and that would bring into play the whole trop vortex in another few days.  

It has often been said we need several bites at the cherry for a really cold spell, well this drawn out sage takes the shortcake, but it is still possible it ends good, because there is literally nothing coming off the Atlantic, so even if it runs into Feb and we keep seeing these attempts to develop a decent ridge, one of them will surely deliver, I would have thought.

It’s ’happening’

 

BFTP

[booferking]

13 minutes ago, Kasim Awan said:

Not seeing any classic wintry conditions the UK can get from a toppler on any output.

The GFS is a sustained mid atlantic ridge & the gem / ecm is a toppling high with the usual temporary wintryness restricted to eastern Europe.

Toppler 1 & 2 glances Scotland and scattered snow showers for Lewis.

Edited January 12, 2022 by booferking

[Kasim Awan]

Until we loose some polar vortex strength & erode some of the Iberian heights, I'd say the pattern shown is unlikeky to deliver.

Edited January 12, 2022 by Kasim Awan

[Staffmoorlands]

8 minutes ago, Anthony Burden said:

 

No sign of anything mild,with day time temperatures heading further south.

 

All the models show a warming trend from this Saturday. I’m still waiting for the cold weather promised for this week

[blizzard81]

11 minutes ago, Mike Poole said:

ECM T240:

I don’t think this chart is likely to verify at all, but if it did, the only option for the high is to retrogress, and that would bring into play the whole trop vortex in another few days.  

It has often been said we need several bites at the cherry for a really cold spell, well this drawn out saga takes the shortcake, but it is still possible it ends good, because there is literally nothing coming off the Atlantic, so even if it runs into Feb and we keep seeing these attempts to develop a decent ridge, one of them will surely deliver, I would have thought.

And couple this with the GFS mean at T264 then we have a very positive development this evening - a rare, albeit tentative, marriage between GFS and ECM.

[Kasim Awan]

3 minutes ago, booferking said:

Toppler 1 & 2 glances Scotland and scattered snow showers for Lewis.

Exactly lol. Even the gfs is very minimal for snow. Will have to wait for the Iberian high signal to begin relaxing.

[Daniel*]

16 minutes ago, Staffmoorlands said:

All the models show a warming trend from this Saturday. I’m still waiting for the cold weather promised for this week

Very briefly on ECM quickly turns colder might turn out to be a reasonable month for frosts.

[steveinsussex]

52 minutes ago, jules216 said:

Its because you dont understand the orography of Slovakia.  A -8  T850hPa under NW will produce a sunny +5 fór me, All the Snow will be blocked by mountains as Well as coldest air.  I get colder temps under slack westerly,even Ice days like today with rising uppers.

Pretty sure you said you wouldn’t moan anymore given your white Xmas?!

[Mike Poole]

ECM clusters T192-T240:

5 of them, and cluster 1 follows the op with 15 members, and this is the one I think has the most potential once we’ve got to this point.  So 30% chance.

The others all look a bit of a mess to me, cold NW’ly from 3 and 5 maybe.  But there is so much uncertainty in this, that is perhaps best to point to the highest probability cluster 1 and leave it at that for now.  But for sure, plenty to watch as the cherry muncher charts his path through the next 10 days…

Edited January 12, 2022 by Mike Poole

[jules216]

3 minutes ago, steveinsussex said:

Pretty sure you said you wouldn’t moan anymore given your white Xmas?!

This is interpreting model output not moaning, the fact that GFS is overamplifying the southerly and westerly direction of trough on 17.01 resulting in more then just a toppler for me being the outlier when EC is showing couple of days of colder uppers its not a moan. Everything is going as expected so there is nothing to moan about 

[stodge]

Evening all

Anticyclonic pretty sums up the evening's output. I did think one or two LRFs proposed such a winter so kudos to those who did. It's January and the Atlantic should be roaring but it's not. It's been far too log since we had a proper frosty, foggy spell with some serious inversion - ice days in favoured locations such as the Midlands can't be ruled out in such a scenario.

Who needs snow?

I've been looking at upstream developments over North America and much talk on their weather blogs of big winter storms this oming weekend and during next week and one of their favourites - a bit of polar vortex coming south into the CONUS and providing some serious cold for all points east of the Ohio Valley and the Great Lakes.

The T+96 charts from UKMO, ECM, GEM and GFS OP

As you might imagine, we've moved into the reliable and the charts are all converging on a major storm system crossing Newfoundland - I had hoped we might see more energy move north rather than NE to provide some WAA up western Greenland and aid Atlantic amplification but the truth is the Atlantic isn't that active.

The second storm doesn't look as powerful as some forecasters in the US were suggesting - the T+156 charts from UKMO, GEM and GFS OP

Still a lot of uncertainty over whether the vortex lobe will push south and fire up another storm - I'm not wholly convinced.  Indeed, the FI profile on the GFS OP keeps the main part of the vortex lobe over northern Canada which enables the HP to remain to the west of the British Isles and we get a feed of chilly NW'ly winds.

Needless to say, Control in far FI is a thing of beauty for cold fans with a real plunge of arctic air in the last week of January - presumably someone's had a visit from Mr Outlier and party !!

[BLAST FROM THE PAST]

58 minutes ago, Kasim Awan said:

Until we loose some polar vortex strength & erode some of the Iberian heights, I'd say the pattern shown is unlikeky to deliver.

You aren’t reading the hemispheric pattern because that’s precisely happening as we go forward.

 

BFTP

[Mariescb]

59 minutes ago, Kasim Awan said:

Until we loose some polar vortex strength & erode some of the Iberian heights, I'd say the pattern shown is unlikeky to deliver.

It's such a shame that the failed chrimbo cold seems to has been a bitter pill to swallow for you. Your once enthusiastic and glass half full posts have been watered down just lately. Bring back the old Kasim, we miss you!

[Cambrian]

A beautiful day here today, frost early and late and a sparkling blue sky, but things are still looking a bit mistier for those seeking some clear signs of winter weather involving precipitation. 

Tracking the GFS ensembles and means through the 12z runs of the last four days - 12z Saturday, 12z Monday and 12z today. 

The transition to average uppers is holding up well, still on course for the 15th. The mean for the period around the 18th to 20th is now comfortably above average for T850s, supporting our goodbye to that chance of a northerly. However, a below average mean now appears for the “new” day 8 / day 9 - the week tomorrow’s potential cold spell is dead, long live the week tomorrow’s potential cold spell. 

Notably, the mean gets progressively colder from that point too and is still below average at the end of the run. However, a more sceptical view could now be that we’re in a modelling pattern with the GFS where the transition to below average uppers (I.e. not the long term average, but below average) is consistently being pushed back to day 8 / 9. The mean for the 18th / 19th on Saturday was near -5, today it’s +1.  The “day 10 syndrome” except at day 8 / 9. This is worth keeping an eye on.

It doesn’t mean it won’t be cold at the surface. Pressure means are exceptionally high throughout, a brief dip around the 16th to near 1022mb, otherwise mostly above 1030mb.

Night / day temperatures across the ensembles mostly gathered between 0 and 8 degrees, trending slowly downwards. 

Some snow chances appear with a good number of members but mostly day 11 and after for any notable cluster. Still, there are plenty in there, so maybe a better outlook for the last week of the month.

For the next week at least then, probably 10 days, looking at the whole pack today - firmly anticyclonic - hopefully more beautiful sparkling days like today. Seasonal but kind weather, which will be a pleasant change for January. 

 

Edited January 12, 2022 by Cambrian

[Kasim Awan]

5 minutes ago, BLAST FROM THE PAST said:

You aren’t reading the hemispheric pattern because that’s precisely happening as we go forward.

 

BFTP

Not seeing much evidence for that personally, as any retrogression seems to coincide with a further build in pressure over the Azores / Iberia, which prevents a southerly undercutting jet.

[Kasim Awan]

4 minutes ago, Mariescb said:

It's such a shame that the failed chrimbo cold seems to has been a bitter pill to swallow for you. Your once enthusiastic and glass half full posts have been watered down just lately. Bring back the old Kasim, we miss you!

Yeah that seemed promising, at one point 50% of the ecm ens & 75% of the gfs ens were going for it big time. This opportunity doesn't warrant the same enthusiasm. I don't mean to bring down the vibe of the chat, it's just that I've seen far too many winters go down the pan and once the slippery slope of locked in Iberian heights start in Dec / Jan, rarely do they reverse.

[bobbydog]

9 minutes ago, BLAST FROM THE PAST said:

You aren’t reading the hemispheric pattern because that’s precisely happening as we go forward.

 

BFTP

 

3 minutes ago, Kasim Awan said:

Not seeing much evidence for that personally, as any retrogression seems to coincide with a further build in pressure over the Azores / Iberia, which prevents a southerly undercutting jet.

 

I think that HP centred over the Russia/Kazakhstan border is the key here. (In this scenario). I've seen this modelled previously. It forces the jet into Europe, the euro high retrogresses and the TPV is forced through the gap, pushing a big cold pool with it.

Its a long way off but it's a plausible evolution.

[damianslaw]

GFS continues to show the ridge further west than ECM and leaves us prone to an eventual polar flow from the NW as the month wears on.. ECM moves heights around clockwise even positioning them further north to pull in a light east drift before sinking them back south and round again and then heading west but also linked back into Iberia. It's a case of watching the high at present... like a slow movie.. gosh I've lost count of how often we have seen heights just sat around the UK never going anywhere fast in the last 14 months.. we seem plagued to have lengthy dry settled spells interspersed with shortlived unsettled spells..

[ANYWEATHER]

To be honest scrolling through the Ecm 12z suite this evening I've never seen high pressure bob around in so many different positions around the uk as much as this run........something is not right and does not follow the law of normal anti-cyclonic behaviour

[SqueakheartLW]

GFS 12z summary

FI looks good for GFS 12z today. It also seems there is a trend to go colder than average, particularly from around the 20th as the ensemble mean line dips below average right to the end of the run.

There are some decent cold charts showing up too after that point, especially towards the end of the run. A good selection from the GFS 12z are below.

Control +360h

P13 +372h

P15 +372h

P16 +372h

P19 +336h

P29 +336h

GEM 12z Summary

If only I could heap the same amount of praise onto the GEM 12z. It appears to not be interested in any cold spell or snap although right at the end of the run its ensemble mean has a small dip below average

Due to the general lack of interest in a cold signal for the GEM the stonking cold charts are rather slim pickings here and I only found 2 that are anywhere near decent in the entire GEM members.

P06 +360h

P17 +372h

Edited January 12, 2022 by SqueakheartLW

[blizzard81]

8 minutes ago, ANYWEATHER said:

To be honest scrolling through the Ecm 12z suite this evening I've never seen high pressure bob around in so many different positions around the uk as much as this run........something is not right and does not follow the law of normal anti-cyclonic behaviour

What is the law of normal anti-cyclonic behaviour? Just out of interest. 

[pdiddy]

---

 

haven't seen a 1080 high modeled recently by GFS...

Edited January 12, 2022 by pdiddy

[Lukesluckybunch]

ICON more amplified on 18z also slightly west!