Model Output Discussion - Into 2024

[warrenb]

I see no change in the mid term trend. Stop looking at individual runs

Individual Ops - 1 to 120 hours

Ens and Means 121 to 192 hours for trend and tend to be reliable

192+ la la land.

[Kasim Awan]

Just now, IDO said:

 

  I have to agree with Kasim here and if we are talking about cold air, then best to post the 850s for a day-to-day comparison:

Today versus yesterday, a clear delay in colder uppers aligned with a general downgrade with pre-D10 cold. You can even see the 0c therm much further east, which highlights my earlier post where the Asia/Russia trough has edged east.

The GEFS showed the same delay and increase in 850s aswell which was a result of more ensemble members trending the pattern north.

[bluearmy]

4 hours ago, Kasim Awan said:

The thing is they are there and they're causing significant issues in advecting cold south. Had heights over the Azores been slightly lower we'd have been looking at a very cold easterly early next week. This is indeed what was modeled a few days ago until the time frame came within scope of models being able to accurately determine the inflation of the hadley cell and shunt out the possibility of an undercut.

 

3 hours ago, Kasim Awan said:

Imo unfortunately there is nothing speculative about the Azores high being a severely limiting factor in this cold spell.

I agree that over the past couple days, the split energy going se hasn’t been well modelled. But it rarely is. Is think the culprit is a runner ne off the esb which heads ne and lifts the Atlantic trough ne. the pattern  ends up further east than originally modelled. And the Azores heights are lifted into our upper ridge.  This is still evolving. 

4 hours ago, Cheshire Freeze said:

Tbf Mike, not long ago we were looking at Icelandic HP this coming weekend…solid means too for this scenario. Now we’re looking at a UK HP.

There’s absolutely no evidence that the same won’t happen for the next D10 chase.

Even with solid background drivers we’re really struggling.

We see this scenario play out year after year these days and people say they won’t be fooled next time and yet they always are.

Not sure Aaron - the eps mean going back 10 days from next Monday seem to have evolved fairly well 

1 hour ago, Kasim Awan said:

Personally I think a west based -NAO is becoming increasingly likely. It makes sense given both the strong signal for retrogression and relatively strong heights to our South.

Can never be discounted in a retrogressive pattern. But at the moment we have a strong upstream n American vortex in place. So hopefully would end up pushing back into the polar ridge and re inforcing the overall neg AO pattern. (This could also be a plus point of the reversal high up not getting below 70N - a really strong regression at 60N may not work if we’d seen a rapid downwelling.  moot point anyway. 

1 hour ago, Scott Ingham said:

The charts are bang on for the 15th nothing is being delayed! Jesus Christ this forum has gone downhill!

Yes - currently highest impact expected 14 to 18th 

47 minutes ago, Lukesluckybunch said:

ECM control does go the West based option...the mean is much better!

ECM control (as per the op) is heavily skewed by that system diving down late in the run. Not worth over analysis although one of the extended clusters does look to be playing with this broad evolution. 

32 minutes ago, Jacob said:

The ECM 850pha temps are a downgrade since last run. Honestly I’m not surprised since most cold spells get watered down closer to the time

What timescale Jacob?   If pre day 10 yes probably but that isn’t the period of interest on 850’s because under a blocking high they are less relevant. 
in the extended, gefs and eps are solidly sub -5c across much of the country 

[Penrith Snow]

It's good practice to compare the countdown to previous cold spells with this potential one as others have done with 2010.

For me this feels more like 2018 as that cold spell was preceeded by a lengthy UK high which then moved northwards allowing very cold easterlies to spread West.

So did it countdown straight forward from FI? Absolutely not! Despite confident MetO MRFs the models wobbled many times and it was only at +120 were we sure the cold spell was nailed, at 10 days out the models were flipping more times than a McDonald's Burger.

For now the trend for an intense Greenland High at day 10 is clear, that's as much as we can expect.

Andy

[jules216]

West based -NAO options are slowly creeping in as usual per post 2016/17 winter standards. Here in central Europe we are paying heavy price for south of Europe being too hot and it takes until spring for stable cold blocking to establish. So a winter of between 2021/22 and 2022/23 is very much unfolding with this west based -NAO gaining traction as models start to see shortwaves that will take prominence and by time sucking the NE Európe cold in to mid Atlantic. Something like late December 2021. This wet pattern since december 2022 is going on forever and 2023 was wettest year since 2010 here in Slovakia but it has to end soon where i see a cold March but mild April for a change hoping to overcome spell of cold springs since 2019. 

[winterof79]

11 minutes ago, Kentspur said:

Remember we were due a white Christmas 2years back then this happened I wonder what effect it may have this time on the models?

 

 

At an X 5, Sunday’s flare was much smaller than the flare recorded in 2003. It was, however, the strongest since September 2017, when an X 8.2 flare was detected, according to the SWPC. This flare also supersedes an X 2.8 solar flare reported in the same region of the sun on December 14. At the time, the SWPC reported that flare was “likely one of the largest solar radio events ever recorded.”

Edited January 3 by winterof79

[Mike Poole]

1 hour ago, TEITS said:

The error that some are making is by not viewing the models from a N Hemisphere perspective. The greenland high is as a result of what is happening to the PV and pressure increasing over the Arctic. The Greenland HP isn't because of our high pressure over the UK this weekend moving into Greenland.

Agree with all your post, but particularly the highlighted bit.  The NH view is essential for model watching in winter because what is happening upstream, over the whole NH and in the Arctic region is absolutely crucial to the fortunes of the UK, and the Europe view doesn’t show it (also the Meteociel Europe view is quite distorted which doesn’t help).  This isn’t true in summer, when the Europe view is more than adequate.  

Edited January 3 by Mike Poole

[winterof79]

1 minute ago, jules216 said:

West based -NAO options are slowly creeping in as usual per post 2016/17 winter standards. Here in central Europe we are paying heavy price for south of Europe being too hot and it takes until spring for stable cold blocking to establish. So a winter of between 2021/22 and 2022/23 is very much unfolding with this west based -NAO gaining traction as models start to see shortwaves that will take prominence and by time sucking the NE Európe cold in to mid Atlantic. Something like late December 2021. This wet pattern since december 2022 is going on forever and 2023 was wettest year since 2010 here in Slovakia but it has to end soon where i see a cold March but mild April for a change hoping to overcome spell of cold springs since 2019. 

Most of those show high pressure to SE Greenland not further West.I posted them earlier to show this.

[Premiere Neige]

11 minutes ago, Kentspur said:

Remember we were due a white Christmas 2years back then this happened I wonder what effect it may have this time on the models?

Not sure solar flares have that much affect on our weather. We are protected from what is ejected from the sun by the magnetosphere. I may be wrong but that's my understanding...

[northwestsnow]

For those interested, and I Inc myself here,these are the night time temps from EC det days 4 to 10 ,just to dispel any notion of downgrades ..

So here is 96 h to 240h

 

[Weather-history]

17 minutes ago, Kentspur said:

Remember we were due a white Christmas 2years back then this happened I wonder what effect it may have this time on the models?

 

 

 Point out that 4 of the coldest winters of the 20th century happened near solar maxima including 1947.

[Lukesluckybunch]

3 minutes ago, northwestsnow said:

For those interested, and I Inc myself here,these are the night time temps from EC det days 4 to 10 ,just to dispel any notion of downgrades ..

So here is 96 h to 240h

 

Not severely cold is it..probably averaging around 0/-1c

[TSNWK]

Just now, Lukesluckybunch said:

Not severely cold is it..probably averaging around 0/-1c

Agree. I was rather underwhelmed with those overnight lows 

[Kasim Awan]

Just now, Lukesluckybunch said:

Not severely cold is it..probably averaging around 0/-1c

By day 3-8C combined with those night temperatures is around 2C below average.

[jules216]

6 minutes ago, winterof79 said:

Most of those show high pressure to SE Greenland not further West.I posted them earlier to show this.

Doesnt matter now. What will matter is the shortwaves which models will see later gaining influence. Only takes a small one to cut off the NE flow to merge through Európe and send cold to far north west. Been here a lot recently in winters sadly. Also MJO is out of synch phase 3 that does usually not mean European wide cold in January.

[northwestsnow]

Just now, Lukesluckybunch said:

Not severely cold is it..probably averaging around 0/-1c

I didn't say severely cold

Lots of frosts around while we wait for retrogression ,it's a good place to be ..

[winterof79]

Sorry to bang on about this but how is this ,the 240z  GEFs and EPS mean Western based.

Western based NAO is west of Greenland

[Kasim Awan]

Just now, jules216 said:

Doesnt matter now. What will matter is the shortwaves which models will see later gaining influence. Only takes a small one to cut off the NE flow to merge through Európe and send cold to far north west. Been here a lot recently in winters sadly. Also MJO is out of synch phase 3 that does usually not mean European wide cold in January.

I have to agree that we are now at a point where it wouldn't take much at all to shift the pattern too far NW.

[Lukesluckybunch]

1 minute ago, northwestsnow said:

I didn't say severely cold

Lots of frosts around while we wait for retrogression ,it's a good place to be ..

I know was just saying

[northwestsnow]

1 minute ago, Kasim Awan said:

By day 3-8C combined with those night temperatures is around 2C below average.

Of course there will be regional variations ..

Temps for Buxton around 2 by day-2/3 by night next week..

 

[Kasim Awan]

Just now, winterof79 said:

Sorry to bang on about this but how is this ,the 240z  GEFs and EPS mean Western based.

Western based NAO is west of Greenland

Not the mean mate but a few individual ensembles plus the issue of a stronger ridge through SW Mediterranean which is a known deflecter of cold.

Just now, northwestsnow said:

Of course there will be regional variations ..

Temps for Buxton around 2 by day-2/3 by night next week..

 

That's around 2c below average here.

[bluearmy]

1 minute ago, winterof79 said:

Sorry to bang on about this but how is this ,the 240z  GEFs and EPS mean Western based.

Western based NAO is west of Greenland

It’s not 

but the means hides stuff and a trend has to start somewhere 

fwiw, I believe the concern on west based is post day 10 as the ridge retrogresses 

[jules216]

1 minute ago, Kasim Awan said:

I have to agree that we are now at a point where it wouldn't take much at all to shift the pattern too far NW.

Agree,and the mean is masking two extreme scenarios to look like blocking is in good place. There are -15 uppers and +5 uppers options here where mean will show a nice -7 value but once the shortwave does appear then its one way outcome not ensemble mean outcome.

[winterof79]

Just now, bluearmy said:

It’s not 

but the means hides stuff and a trend has to start somewhere 

fwiw, I believe the concern on west based is post day 10 as the ridge retrogresses 

Yes,post day 10.

Lets see how it transpires.

[northwestsnow]

2 minutes ago, Kasim Awan said:

Not the mean mate but a few individual ensembles plus the issue of a stronger ridge through SW Mediterranean which is a known deflecter of cold.

That's around 2c below average here.

I suspect ,and I may be wrong ,there will be cloud spilling in off the North Sea at times ..

Could well be west of the country sees the colder temps,certainly at night..