Model discussion: Hunt for cold - The start of 2022

[Nick F]

34 minutes ago, Daniel* said:

AO now expected to stay in negative territory going ahead.

I imagine ECM control was a stonker strong -NAO and -AO blocking, hemispherically the outlook is improving…

 

Trouble is, we had a -AO during the second half of December but managed to be generally mild in the UK. Record Mild New Year and the AO was still -ve!

12z EC Day 10 NH and can see the -AO footprint of +ve heights/pressure over the pole, but not really forcing the jet stream south.

Ideally we need height rises over Greenland to help us separate the stronger NE Europe / NW Russia TPV lobe and the Canadian TPV lobe. Signs in the 10-15 day EPS mean we could achieve this with a very elongated TPV being pinched from Atlantic ridging and Alaskan ridging. But its a long shot.

 

Edited January 9, 2022 by Nick F

[damianslaw]

Sticking to the reliable - roughly 120 hrs, it is a generally chilly quiet outlook, high pressure nosing in again this time more concertedly to anchor itself over southern britain. At this time of year its a recipe for frost and fog, temps by day could struggle for some towards latter of the week, much will depend on the extent of cloud cover. Further north, a milder feed off the atlantic, meaning Scotland and N Ireland will be milder than England and Wales - not an unusual scenario when heights position themselves in this manner.

Looking into mid January, all rather messy at the moment, and am refraining from comment as a result.

[minus10]

36 minutes ago, Nick F said:

I think the differences between models and between their own runs today over the Atlantic sector, particularly GFS between 06z vs 12z, stem from the uncertainty upstream of the track of storm that they blow up off the eastern seaboard later in the coming week.

GFS on both 06z and 12z keen to keep the deepening low close to the eastern seaboard as it tracks NE into the weekend, but 12z diverged from the 06z by taking the storm NE over S Greenland then on towards Iceland, whereas the 06z had the low move north towards Baffin Bay, allowing/forcing high pressure to ridge north towards Iceland with a northerly developing downstream over UK and N Sea. 

EC had differences between its 00z and 12z runs over the deepening of the low and track, 00z less developmental and drifting east out over NW Atlantic, 12z deeper and closer to the eastern seaboard but eventually filling and moving out into the NW Atlantic - both scenarios not allowing highs to ridge north for long over the Atlantic and allow a northerly over the UK.

Once the models sort out the track and development of the low off the eastern seaboard, then we may get some consistency. Mind you the models bring further lows out of eastern US and develop them - which goes to show the active pattern upstream over eastern N America and NW Atlantic vs the stagnant pattern over western Europe and NE Atlantic sector. How the models handle this contrast and which will override which remains to be seen!

Yes I think this will be one to watch Nick as it seems fairly important as to how things turn out after. not looking too good at the moment although still time . Would want gfs 6z type of solution to bolster the heights...

 6z gfs12z gfs12z ecm

 

 

 

[stodge]

1 hour ago, Nick F said:

I think the differences between models and between their own runs today over the Atlantic sector, particularly GFS between 06z vs 12z, stem from the uncertainty upstream of the track of storm that they blow up off the eastern seaboard later in the coming week.

GFS on both 06z and 12z keen to keep the deepening low close to the eastern seaboard as it tracks NE into the weekend, but 12z diverged from the 06z by taking the storm NE over S Greenland then on towards Iceland, whereas the 06z had the low move north towards Baffin Bay, allowing/forcing high pressure to ridge north towards Iceland with a northerly developing downstream over UK and N Sea. 

EC had differences between its 00z and 12z runs over the deepening of the low and track, 00z less developmental and drifting east out over NW Atlantic, 12z deeper and closer to the eastern seaboard but eventually filling and moving out into the NW Atlantic - both scenarios not allowing highs to ridge north for long over the Atlantic and allow a northerly over the UK.

Once the models sort out the track and development of the low off the eastern seaboard, then we may get some consistency. Mind you the models bring further lows out of eastern US and develop them - which goes to show the active pattern upstream over eastern N America and NW Atlantic vs the stagnant pattern over western Europe and NE Atlantic sector. How the models handle this contrast and which will override which remains to be seen!

I commented on this earlier today and again this evening.

What do you make of the UKMO forecasting of this American storm? The T+168 this morning and this evening both suggested a more NNE'ly track for the LP as it passed over Newfoundland and this allowed amplification much further north and west than some of the other models.

[Nick F]

10 minutes ago, stodge said:

I commented on this earlier today and again this evening.

What do you make of the UKMO forecasting of this American storm? The T+168 this morning and this evening both suggested a more NNE'ly track for the LP as it passed over Newfoundland and this allowed amplification much further north and west than some of the other models.

Yes, 12z UKMO at t+168 certainly different over the far N and NW Atlantic than 12z GFS - because of the different track of that storm up the ES towards New Foundland.

By the way though, those expecting a repeat on the 18z of the 06z GFS maybe disappointed to know that the US NWS WPC forecast binned the 06z GFS after day 5: https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

Though the uncertainty over placement of highs and lows over the N Atlantic  after day 5 may rumble on ...

 

[Ciderman]

4 minutes ago, Nick F said:

Yes, 12z UKMO at t+168 certainly different over the far N and NW Atlantic than 12z GFS - because of the different track of that storm up the ES towards New Foundland.

By the way though, those expecting a repeat on the 18z of the 06z GFS maybe disappointed to know that the US NWS WPC forecast binned the 06z GFS after day 5: https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

Though the uncertainty over placement of highs and lows over the N Atlantic  after day 5 may rumble on ...

 

Cautious optimousim maybe

[Winter Hill]

3 hours ago, Kasim Awan said:

Azores high again lol.

What was the Spanish Met winter forecast for this winter? 

2 years ago they forecast a drier than average winter for Iberia and they were bang on !! The Azores high killed winter in this country. 
 

I’m seeing the same outcome now.

[Cambrian]

24 hour GFS ensemble “slidograph” to illustrate the maintenance of the period of below average uppers modelled by the GFS at 12z yesterday through today’s runs, although clearly not so cold on today’s runs.

On the left, GEFS T850 spread at 12z yesterday, 0z and 12z today, the slightly slanted lines link the same time on each graph to account for the intervening 12 hours. The same approach can be used, better over a few days, to see if a modelled change, say at day 10  is being pushed back in consecutive runs.

Here, it’s charting the ensemble mean crossing the 0 degree line, which also happens to be the long term average, modelled at 12z yesterday for the 15th, remaining sub-zero until the 24th. 

The expected time of arrival and duration of the colder air has not changed across the three ensemble sets, though clearly the coldness of the mean has, from around -4 to -3 to -2/-1.

On the right, the same for barometric pressure, the mean already dropped to 1025mb by the 16th on yesterday’s 12z run, still on its way down on the 0z run, and never gets as low as 1025mb on today’s 12z run. So a nice graphical representation of the effects of the stubbornness of the Azores high refusing to move south to let the trough drop down from Iceland to fully introduce the colder air. 

However, the mean from today’s 12z run masks a high degree of ambiguity, even at day 7, as @Mike Poole pointed out for the ECM above, the same applies to the GFS, with the ambiguity hotspot in a similar position near Iceland, but also notable spread southward towards Scotland, as well as westward towards the eastern seaboard, emphasising the questions around the exit track of the storm there, alluded to by @stodge and @Nick FIndeed, it can also be said that the stronger confidence for the placing of the Azores high is reserved only for its southeast quadrant towards Spain.

An unusually high spread for day 7, with a low grasp of upstream events over the other side of the Atlantic, which might as easily ultimately equate to a deeper and colder trough to our north and a more southerly positioned Azores high as indicated on yesterday’s ensembles.

 

Hopefully some better signs and more clarity over the next couple of days.

[Nick F]

18z GFS looks more amplified than 12z day 7-8 over the Atlantic as the upper ridge centred near Ireland builds north towards Iceland, but the subsequent northerly downstream is too far east over Scandi/Denmark to benefit us, with high pressure moving back over the UK. If only the high could move further west! Still, past day 5 there will be further changes ahead ...

[northwestsnow]

18z setting up a late night treat .?

[Singularity]

Considering the trend to re-amplify the Pacific standing wave during week 3 of Jan, I have a feeling we’re going to be teased with northerly chances for quite a while. Maybe even most of the rest of January.

Who knows, one mid-Atlantic ridge build might find a space to get its foot in the Arctic door and produce more than a brief glancing blast of cold air for the UK - but which one and how soon that is is anyone’s guess. For now, best just to sit back and keep one eye on the ensemble clusters rather than pay much attention to individual runs.

[Ali1977]

A much improved day 7 mean and ENS, many have height rises around Labrador off the back of the LP running up the Eastern seaboard. This is what needs watching. 

 

The weaker PV over Canada on latest mean compared to the 12z here. This is day 7, hopefully things will fall like the above ENS and a big flip by models to this tomorrow.

Edited January 9, 2022 by Ali1977

[Ali1977]

P5 and P2 are the coldest I’d say  there are plenty milder ones too though sadly

Edited January 9, 2022 by Ali1977

[Nick F]

Yep, think a few more brief northerly topplers is the best we can hope for over the next few weeks unless somehow we can split the TPV stretching between N Canada and N Russia into two separate trop vortices and allow some height rises over Greenland. Not out the realm of possibilities, with the extended EPS hinting at cross polar ridge pinch on the elongated TPV, but a tall ask for now. 

Edited January 9, 2022 by Nick F

[Battleground Snow]

37 minutes ago, Ali1977 said:

A much improved day 7 mean and ENS, many have height rises around Labrador off the back of the LP running up the Eastern seaboard. This is what needs watching. 

 

The weaker PV over Canada on latest mean compared to the 12z here. This is day 7, hopefully things will fall like the above ENS and a big flip by models to this tomorrow.

Great work keeping the cold hunt going this evening @Ali1977

Control run is very nice, the low hangs back enough to allow the ridge.

nice to see the OP was way above the mean too .

-20 has appeared on the wetterzentrale axis (just for fun)

Lets see how the morning runs go, I'm encouraged by the negative AO development for the longer term today though

Edited January 9, 2022 by Battleground Snow

[booferking]

25 minutes ago, Ali1977 said:

P5 and P2 are the coldest I’d say  there are plenty milder ones too though sadly

P2 is a beauty it forms a very rare polar low between Greenland & Iceland and drops it south through the country

Edited January 9, 2022 by booferking

[weathermadbarnsleylad]

Still a spread on the 18z ens from the 16/17th Jan onwards for cold spell development. All those on here saying no cold at all showing need to see the below chart . Until they all have agreement I still believe a cold spell is possible. 850hpa temps south Yorkshire below.

[FENDER.]

Possible perhaps.  But not very likely. 

Need a major patern change ASAP, and little sign of that in the near future.

 

[The Enforcer]

47 minutes ago, weathermadbarnsleylad said:

Still a spread on the 18z ens from the 16/17th Jan onwards for cold spell development. All those on here saying no cold at all showing need to see the below chart . Until they all have agreement I still believe a cold spell is possible. 850hpa temps south Yorkshire below.

That chart does demonstrate that it is a reasonable expectation for the UK to receive a polar maritime air mass for a couple of days or so, before the mobility of the overall current pattern moves it on. The good news for the UK is that the polar maritime air source in question appears to be stronger than in recent years. Therefore, whilst the time it spends here may be limited, it could still have a significant impact.

[weathermadbarnsleylad]

38 minutes ago, The Enforcer said:

That chart does demonstrate that it is a reasonable expectation for the UK to receive a polar maritime air mass for a couple of days or so, before the mobility of the overall current pattern moves it on. The good news for the UK is that the polar maritime air source in question appears to be stronger than in recent years. Therefore, whilst the time it spends here may be limited, it could still have a significant impact.

Has it still is days away it can still also upgrade or downgrade. My only thinking with models this winter is they really struggled with Xmas blooper cold spell prediction. So I would say anything after 72/96hr can change either way. Seen has I'm a coldie I'm hoping for upgrades on the 00z. Maybe thats why I'm maybe clutching at straws and a bit bias. But even if I wasn't I still think something special is around the corner for a decent cold spell. I just think it's a very strange winter and surprises will happen at a very short time frame.

 

[Battleground Snow]

Ukmo, GFS and gem at 168,

GFS goes on to give glancing blows of cold, but nothing of note. Gefs still has huge scatter around the 18th

AO trending more negative still across the models,

We await the ECM

 

Edited January 10, 2022 by Battleground Snow

[Jamesjane]

I will take that from the UKMO

[Ali1977]

Big 3 at T168 - some consistency finally. No big northerly though!! 
UKMO might look best over the U.K. but it also has the biggest build of PV over Canada!! 

[PiscesStar]

17 minutes ago, Ali1977 said:

Big 3 at T168 - some consistency finally. No big northerly though!! 
UKMO might look best over the U.K. but it also has the biggest build of PV over Canada!! 

It's early days on these charts but at the moment that wedge looks primed to head northwards... 

[That ECM]

Unusual for me not to post nhp view but this highlights at T144 Ukmo being different to the other two. Need this sorting before looking at later output.