Model discussion: Hunt for cold - into mid-January

[Hull 1963]

According to a BBC weather forecast yesterday. They said that WXCharts show that sub zero temperatures will be back on January 31 with heavy snow fall expected in the first week of February in the north.

[Cambrian]

The big watch for me this afternoon besides how we do away at Palace is the UKMO development of the cold snap for next weekend.

We’ve been understandably so busy looking to the south for signs of a relenting in the heights anchoring the high pressure so steadfastly nearby, that perhaps we’ve overlooked potential events to our north that could deliver a knockout punch and a pattern change.

The differences between the 12z run yesterday and the 0z today are in the timing and extent of deepening of the low pressure to our north. 

At 144h from 12z yesterday compared with 132h from the 0z, the 980mb low to the east of Iceland is just not there at all on the 0z.

 
 

The development is held back to the next 24 hours on the 0z run. At 168h from 12z yesterday compared with 156h from the 0z, the low in yesterday’s run had moved back west to just west of Iceland, with no further deepening. On the 0z run, it’s moved east to the Norwegian Sea and deepened into a proper winter storm, lower than 960mb central pressure.

 

As a result, it’s a profoundly different setup for day 7. At 168h on the 0z, the low has maintained its depth and is now right over Scandinavia, with most of the UK in a cold air mass with -4 to -8 uppers. There is promising northward ridging of the Atlantic high to Greenland, which might be prolonged by a slowly developing low off Newfoundland that’s not moving anywhere fast and the low at the western lobe of the PV being markedly shallower at that stage. 

 

Hopefully not just there for one run, as this would be a proper winter storm within a week that could pave the way for an interesting pattern change at a crucial juncture in our winter, going into February with a chance of some very cold air being pointed our way from the Arctic Ocean around Svalbard. Even with modification, it will be a very different feeling month if we can tap into the occasional blast from there. 

[feb1991blizzard]

19 minutes ago, Hull 1963 said:

According to a BBC weather forecast yesterday. They said that WXCharts show that sub zero temperatures will be back on January 31 with heavy snow fall expected in the first week of February in the north.

Have you got the video please?  It must be a single GFS op run that they're going off.

[BLAST FROM THE PAST]

9 minutes ago, feb1991blizzard said:

Have you got the video please?  It must be a single GFS op run that they're going off.

Looks like thy are going off the UKMO?

 

BFTP

[MJB]

13 minutes ago, feb1991blizzard said:

Have you got the video please?  It must be a single GFS op run that they're going off.

They wouldn't go off GFS 

[feb1991blizzard]

5 minutes ago, BLAST FROM THE PAST said:

Looks like thy are going off the UKMO?

 

BFTP

must be this.

[*Stormforce~beka*]

52 minutes ago, Hull 1963 said:

According to a BBC weather forecast yesterday. They said that WXCharts show that sub zero temperatures will be back on January 31 with heavy snow fall expected in the first week of February in the north.

Even they are clutching at straws lol!

[Cold Winter Night]

To me, the cold perspective for February is beginning to look a bit better now than a couple of days ago. To me, the output is getting more interesting again.
Extended clusters seemed to lean towards the setting up of a NAO+ pattern, but yesterday and today there are some signs appearing that this may not be the direction we're going. all still tentative though, without any promise or certainty of our preferred outcome.

GFS/GEFS keeps showing nice charts in FI, but it has done so for many weeks now, without them verifying. So I'd say: "Thanks GFS, for keeping spirits high, but a bit more reliability would be nice once in a while too."

GFS moves that trough into Scandinavia, UKMO is interesting at 168h for doing the same.

ECM Op is flatter, but is at odds with the majority of its ensemble. Many members have a more amplified Atlantic ridge and the trough further Southeast into Scandinavia, more like UKMO/GFS. This is also visible on the regimes chart, which moves towards BLO- (Scandinavian trough, Atlantic Ridge) at day 8.

The more amplified clusters will increase chances of snow, especially at higher altitudes. The turn of the month will be intersesting in that regard.

After that, the EPS 192h-240h doesn't let that ridge get a firm grip, but a NW-SE tilted flow is clear, mobile Atlantic.

The extended clusters, out to 360h, are the most interesting to me.
Possible pressure rises to the Northeast (Ural and Scandinavia), or Northwest (NW Atlantic/Northern Canada) draw attention.

I can't see a traditional NAO+ setting up into February with those developments in the Northern Hemisphere. We might see more blocking Highs over us, more NW influences, or more NE influences.
That Ural High might very well retrogress into Scandinavia, or connect to Atlantic ridging. Although it doesn't bring cold to our part of the world within the 15 day period, still those nice GEFS don't seem as completely outlandish anymore.

[Cold Winter Night]

2 hours ago, SqueakheartLW said:

Just out of curiosity decided to see what the 500hpa anomaly has been so far for this winter. This is what I got for the period 1st December to the latest it allowed me to, 20th January.

So far a bit of northern blocking showing up which is what you would probably expect to see in an EP La Nina year and looking at that you would think things would have been cold so far with the UK at the tail end of above average anomalies that stretch right back into the polar regions.

That anomaly chart for the winter so far is very interesting.

What stands out most to me:
- Pacific High almost as stationary feature.
- Azores Low anomaly, the opposite of the presumed stronger Azores High some here blame as a hindrance to cold patterns.
- Almost textbook NAO-, with those West-European/UK heights making it more borderline BLO+.
- Generally High anomaly over the Arctic, associated with a weak tPV.

Just looking at this chart, I think many would assume this was a colder winter, illustrative of how these anomaly charts can deceive.

[Ali1977]

Icon not delivering full on low ground snow but it’s bringing back more typical Jan weather, cold wet and windy. Good for the Scottish ski resorts that’s for sure

 

There is a little LP moving through though, maybe a few surprises for some (Welsh hills anyway)

Edited January 23, 2022 by Ali1977

[chapmanslade]

1 hour ago, feb1991blizzard said:

Have you got the video please?  It must be a single GFS op run that they're going off.

 

1 hour ago, BLAST FROM THE PAST said:

Looks like thy are going off the UKMO?

 

BFTP

 

1 hour ago, MJB said:

They wouldn't go off GFS 

I'm sure @fergieweather will not mind me copying and pasting this from the previous thread on what BBC use:

 

No worries! I assume the misconception is simply because the primary deterministic global model we use on TV graphics is ECMWF (although we can, & some of us periodically do, also show GFS & UKMO-GM for comparative purposes such as the lead-up saga we endured into Christmas Day). The principal mesoscale/regional model we used was, until a fortnight ago, Euro4 (with its raw output edited as needed by DTN forecast team). However with that model now retiring, we've switched to UKVx as the default. None of this feeds into the app, however - both it, plus TV site max/mins & 7-day outlooks are MOS driven, as prior explained. Cheers 

[blizzard81]

Amazingly warm uppers heading up the east coast of Canada. Just look at the them clashing with the frigid uppers. Amazing to see. 

[minus10]

Well that makes a change for the start of February !!

[Cold Winter Night]

No one about the 12z's?

They're not bad at all.

UKMO interestingly most amplified at 168h:

And GFS in FI doing its best 1947 imitation, not a bad attempt at all, this Scandi High setting up,
GFS 312h first, then January 20, 1947:

[MJB]

Interesting 

[Battleground Snow]

GFS still teasing  in FI, but the sheer depth of cold in Canada is really not helping us out.

[Battleground Snow]

Gem throwing a big negative AO at day 10,

Hemispherically things are interesting, but it's not falling right for the UK as of yet.

[Tim Bland]

06z Vs 12z I’d say that’s pretty consistent for 14 days out 

[minus10]

Year right......

 

[johncam]

4 minutes ago, Tim Bland said:

06z Vs 12z I’d say that’s pretty consistent for 14 days out 

The problem Tim is more often than not that far out it is wrong  

[Catacol]

4 hours ago, SqueakheartLW said:

In theory going by this chart the coldest anomalies are east of 150W with a particular focus on the 120W to 90W region so that would suggest this is an EP La Nina.

However the atmosphere seems to be acting more like we are in a CP La Nina setup with a +NAO and strong vortex.

For the first half of winter the atmosphere was engaged in Nino style forcings - active pacific, above average GLAAM. GWO was in a decent orbit giving all the early enthusiasm for potential blocking. Only now are we seeing the atmosphere slide into a Nina state, hence the fears of a +NAO Feb underpinned by a vortex with no dents.

As I wrote in a previous post the pacific seems pretty active through winter in the christmas pudding. Spikes in momentum causing amplified patterns are observationally common, but the USA is getting most of the benefits of this with downstream Atlantic blocking much harder to make stick. For all of the gloom of the present I do think we have a chance of an interesting March. The vortex will be weakening, maybe even feeling the heat after a period in February where vertical flux looks likely to increase, and assuming the pacific stays active we have chances of a block to our north. Given MJO cycle it might kick off late February - if it happens. Best I can see at the moment.

[Cuban Zebra]

I’ve tried to be optimistic but that’s now gone!

I have an awful feeling we’ll be crying out for charts like this in the summer!!

 

[shunthebartlett92]

1 hour ago, Battleground Snow said:

Gem throwing a big negative AO at day 10,

Hemispherically things are interesting, but it's not falling right for the UK as of yet.

What i cant understand (this is one for those with more met knowledge than i do), is why that trough digging well into E/SE europe cannot move just 500 miles further west but it just never does. I would imagine the jet stream is the significant influencer here, its too strong to allow a NW-SE aligned trough to persist for any length of time, and the other blinking irritating factor in UK synoptics, the azores high!

[Ali1977]

Well the NH is looking interesting on many ENS on the latest run - all very diff to nothing can be drawn from it!! 

[mountain shadow]

24 minutes ago, Ali1977 said:

Well the NH is looking interesting on many ENS on the latest run - all very diff to nothing can be drawn from it!! 

Of the hundreds upon hundreds of individual "interesting " ensembles members that have been posted on this thread, this Winter, on this thread,  zero have verified.  Zero.

Whilst the trop PV remains entrenched over NE Canada,  there is very little chance of anything interesting occurring.