Model Output Discussion - Colder spell ending, what's to follow?

[blizzard81]

3 minutes ago, Kentish Snowman said:

Can I just ask why a solar flare headed for Earth would scupper the chances of cold in the UK?

What would the mechanics be behind it?  Would it only affect cold chances in the UK / Europe or would it have more of an effect globally?

I only ask as we have enough to worry about here on Earth with ENSO QBO MJO UKMO etc without worrying about UFOs as well?

That aside the 6z GFS looks very promising for a cold pattern to become established in the medium term! 

TIA

Ha ha I like the UFO comment lol. As I have just posted, I am a novice in this field to say the least. Increased solar CME's directed towards earth seem to fire up mobility, especially in the atlantic causing more wet and windy weather for north west Europe. Even Glacier Point alluded to this a few years ago. That's my very simplistic view on it lol. 

[ALL ABOARD]

A glitch but I actually love this view? 

Puts everything we all love into perspective. 

Seeing our beautiful planet doing its thing. 

Looks like we're viewing from space. 

[Methuselah]

Well, I'd be remiss, were I not to post this morning's GFS 06Z at t+384... so, here it is!

    

And, woe betide anyone who says is had no potential! Developments on Nimiru notwithstanding of course!

[bluearmy]

1 hour ago, blizzard81 said:

Yep, quite a major earth bound solar flare. Possible impact tomorrow or Thursday. Not good news at all. Really bad timing and solar activity has increased quite markedly over the last 2 to 3 weeks. From past experience, I wouldn't be surprised to see the NWP move away from any potential end of December cold by this coming weekend. We will then be looking into Jan. Still early days of course but I'm getting that slippery slope kind of feeling. 

I appreciate your worries here but I wonder if an uptick in the Atlantic jet is a big risk if we get the Arctic pattern right - a stronger jet into Iberia could actually work in our favour ....

The most encouraging factor on that gfs 06z op for me is way off in fi where what looked to me like a slam dunk west based -NAO didn’t actually destroy winter for the U.K. as the run entered week 3. No sou’wester for us on that run ! whilst the run is likely for the birds, i felt that part was interesting....

 

[Uncertainty]

15 minutes ago, Steve Murr said:

The 06z Mean at 168 > the 00z 174 mean

Shows everything moving in the right direction at the right timeline

* Svalbard troughing better alligned

* Blocking more developed over Greenland

* Atlantic ridge better defined

 

 

Indeed Steve and flicking through the ens at day 9 a good many of them are going down similar routes to the op... there’s gonna be some stunners in there.

An excellent trend 0z vs 6z

 

The centre of the blocking now well west of the meridian and lower heights moving south east towards Iberia.

As to the Eps I flicked through them all there’s so many options in there that you can understand why the cluster algorithm went for one cluster when, in reality, there’s almost every hemispheric permutation you can think of! There are many which end up slightly blocked but still have south westerlies for the UK but there are many that don’t and go onto to signpost easterlies.

The GEM ensembles near to Christmas have a very unusual anomaly indeed.

I really hope the latest Glosea seasonal gives some credence to this potential  January SSW, it’s so frustratingly accurate these days in Winter. It would be brilliant to have it on board for the mid winter period.

Genuinely fascinating model watching at present. 

 

[Sawel]

2 hours ago, Updated_Weather said:

Has the UK ever seen -20 uppers before? I don't think I have ever witnessed it since i've been born in 96!

A scan of the archives (since WW2) focusing on the most severe easterly outbreaks the UK has experienced would suggest that the -20c uppers may have clipped the extreme SE of England in February 1956 and/or January 1987. These two cold spells had the deepest cold pools. It's impossible to tell for sure from these charts if the -20c did hit our shores but we can say that at the very least, we have come extremely close.

1956 and 1987 charts...

 

Edited December 8, 2020 by Sawel

[Kentish Snowman in Yorks]

6 minutes ago, Sawel said:

A scan of the archives (since WW2) focusing on the most severe easterly outbreaks the UK has experienced would suggest that the -20c uppers may have clipped the extreme SE of England in February 1956 and/or January 1987. These two cold spells had the deepest cold pools. It's impossible to tell for sure from these charts if the -20c did hit our shores but we can say that at the very least, we have come extremely close.

1956 and 1987 charts...

 

We must have been not far off in February March 2018 either?

If we get anything close to that over the festive period I think most on here will be happy.  Certainly the possibility is higher this year than most it seems.

Will be nice to see the 12z runs start trending colder in the mid term this afternoon a la the UKMO run from this morning and the 6z GFS....

[danm]

1 minute ago, Kentish Snowman said:

We must have been not far off in February March 2018 either?

If we get anything close to that over the festive period I think most on here will be happy.  Certainly the possibility is higher this year than most it seems.

Will be nice to see the 12z runs start trending colder in the mid term this afternoon a la the UKMO run from this morning and the 6z GFS....

Looks like the coldest uppers in 2018 was the -16c line clipping the east coast:

[ITSY]

9 minutes ago, Sawel said:

A scan of the archives (since WW2) focusing on the most severe easterly outbreaks the UK has experienced would suggest that the -20c uppers may have clipped the extreme SE of England in February 1956 and/or January 1987. These two cold spells had the deepest cold pools. It's impossible to tell for sure from these charts if the -20c did hit our shores but we can say that at the very least, we have come extremely close.

1956 and 1987 charts...

 

Only in the interests of expectation management, I dare add that these two  charts have a critical component that we're lacking into the foreseeable - entrenched and deep low pressure centered across southern Europe and the central Mediterranean. (Of course this may yet materialize - or may not).

If we want the golden goose easterly (which is by no means what everyone wants - even for me in Cambridge a true NE'ly tends to be better) then that's what we need - heights to the north east and low pressure to the south east. 

[alexisj9]

1 hour ago, Cold Winter said:

Quick reminder on how different one run to the next can be once you get past T144...... particularly when you’re thinking about the micro-effects on our little slice of the world.

 

With how we are now, and the strength of the Russian block, it's charts like this, I've been expecting. I'm still not sure on the SW warm up most see coming, and neither are the models yet. Still more runs needed, we should know by 0z I hope.

[Sawel]

6 minutes ago, Kentish Snowman said:

We must have been not far off in February March 2018 either?

If we get anything close to that over the festive period I think most on here will be happy.  Certainly the possibility is higher this year than most it seems.

Will be nice to see the 12z runs start trending colder in the mid term this afternoon a la the UKMO run from this morning and the 6z GFS....

February and March 2018 was exceptional but uppers maxed out around -17c. February 1991 was exceptional too and Uppers seem to have maxed out just short of -20c.

[heath]

Thinking of an analogue to the GFS06z op today I wondered about December 1978 from memory. 

[Ali1977]

-12/14c uppers covering most the country in 2018, -16/18c In 1987. Both Epic cold really but 87 in a diff league with daytime max nearer -6c . I’d love to see that again in my lifetime, I think

Edited December 8, 2020 by Ali1977

[alexisj9]

25 minutes ago, Sawel said:

A scan of the archives (since WW2) focusing on the most severe easterly outbreaks the UK has experienced would suggest that the -20c uppers may have clipped the extreme SE of England in February 1956 and/or January 1987. These two cold spells had the deepest cold pools. It's impossible to tell for sure from these charts if the -20c did hit our shores but we can say that at the very least, we have come extremely close.

1956 and 1987 charts...

 

I remember Jan 87 that when my school closed cause of frozen water pipes. Over night temps well below zero.

[Nick F]

56 minutes ago, carinthian said:

Would be nice Nick to have UKMO/ECM this evening start to fill that Atlantic Low next week and send its trough into the continent. Lets hope GFS is now onto something good  ,

C

So long as the TPV stays over Canada, with +ve heights into Greenland, which is backed by ensemble means, then any energy uptick over the N Atlantic, as lobes of the Canadian TPV breakaway eastwards, will be short-lived - which means lows will fill quickly rather than spin up into deep depressions that we so often see in December.

And with the decent signal for +ve heights / blocking showing from the 06z GEFS mean to our N into Greenland, the jet will hopefully be forced on a more southerly track across Atlantic into Europe too as we head through next week.

[blizzard81]

37 minutes ago, bluearmy said:

I appreciate your worries here but I wonder if an uptick in the Atlantic jet is a big risk if we get the Arctic pattern right - a stronger jet into Iberia could actually work in our favour ....

The most encouraging factor on that gfs 06z op for me is way off in fi where what looked to me like a slam dunk west based -NAO didn’t actually destroy winter for the U.K. as the run entered week 3. No sou’wester for us on that run ! whilst the run is likely for the birds, i felt that part was interesting....

 

Indeed. I also had this in mind whilst posting. Overall, despite the uptick, solar activity is still in its low phase. So, this should aid the southern arm of the atlantic. We would therefore hope for 'southerly' tracking lows as opposed to northerly tracking ones. Like you say, the arctic high could also be a beneficial factor - keeping the lows on a southerly track. Again, 1947 springs to mind. Don't think the sun was quiet that year either. I hope I was just being too pessimistic with my earlier post. 

[pdiddy]

53 minutes ago, ALL ABOARD said:

A glitch but I actually love this view? 

Puts everything we all love into perspective. 

Seeing our beautiful planet doing its thing. 

Looks like we're viewing from space. 

Christmas Eve view!

[Bricriu]

2 hours ago, blizzard81 said:

Yep, quite a major earth bound solar flare. Possible impact tomorrow or Thursday. Not good news at all. Really bad timing and solar activity has increased quite markedly over the last 2 to 3 weeks. From past experience, I wouldn't be surprised to see the NWP move away from any potential end of December cold by this coming weekend. We will then be looking into Jan. Still early days of course but I'm getting that slippery slope kind of feeling. 

Speaking of Solar Flares, was it a Solar Flare that Stuart Rampling(GP) pointed to as scuppering an easterly he had envisaged back in 2013? It was all looking so good, then a few days out it all went pear shaped.

[danm]

19 minutes ago, Ali1977 said:

-12/14c uppers covering most the country in 2018, -16/18c In 1987. Both Epic cold really but 87 in a diff league with daytime max nearer -6c . I’d love to see that again in my lifetime, I think

Yep and 1987 also had the advantage of occurring in the depths of winter rather than the start of meteorological Spring, as was the case in 2018. 

[Catacol]

2 hours ago, blizzard81 said:

Yep, quite a major earth bound solar flare. Possible impact tomorrow or Thursday. Not good news at all. Really bad timing and solar activity has increased quite markedly over the last 2 to 3 weeks. From past experience, I wouldn't be surprised to see the NWP move away from any potential end of December cold by this coming weekend. We will then be looking into Jan. Still early days of course but I'm getting that slippery slope kind of feeling. 

Let's put this one to bed. A single C class flare does not constitute a major uptick in solar activity. The sunspot number remains low - though yes: we are on the way back up now as we head into cycle 25. The reports are of "very low" and "low" activity with only a single sunspot currently visible. There is no issue here. The best place to get a quick summary of the current position is here:

StackPath

WWW.SPACEWEATHERLIVE.COM

 

 

[lawrenk]

7 minutes ago, danm said:

Yep and 1987 also had the advantage of occurring in the depths of winter rather than the start of meteorological Spring, as was the case in 2018. 

87 remains “the one” for me, possibly because I was the right age to appreciate it, but never known cold like it or for snow to stay on the ground for so long.

[Ali1977]

Just now, Catacol said:

Let's put this one to bed. A single C class flare does not constitute a major uptick in solar activity. The sunspot number remains low - though yes: we are on the way back up now as we head into cycle 25. The reports are of "very low" and "low" activity with only a single sunspot currently visible. There is no issue here. The best place to get a quick summary of the current position is here:

StackPath

WWW.SPACEWEATHERLIVE.COM

 

 

Agree, a solar flare in solar minimum is probably about as powerful as fleas fart.
 

There’s nothing notable pushing us towards a mild winter so all to play for, anything like the latest GFS and it’s game on!! I don’t like these winters where we are relying on an SSW so let’s hope for something proper cold this side of new year when we have nice short daylight hours!! 

[Catacol]

Some great stuff on the 06z - though we know it wont be quite like that come zero hour. The trend towards stronger northern blocking on the back of the AAM momentum post from yesterday continues, though in that context the ECM this morning is a bit underwhelming.

The GFS prediction of a pacific jet surge is still there. The current run pushes it back a couple of days - but it is definitely there.

Think of the pacific jet as the sping that fires the pinball onto the machine board. The momentum that comes from the pacific jet is what begins much of our amplification processes, pushing hard at the atmosphere ahead and forcing poleward wave breaks on the northern side. Where those wave breaks then occur is the conundrum, but I think our atlantic context is going to be predisposed to this given the impacts of forcing on the vortex already discussed. We now have a clear separation of the vortex on the strat/trop boundary forecast for 10 days' time

a gentle increase of the wave 2 pinching on the vortex at the same point

and that sustained wave 1 signal is still there

Nothing about this is bad. As posted previously an atlantic spell mid month of some kind was always likely because our slow moving block is not a monster (yet) and atlantic energy looks to be splitting pretty much right over the top of us....ergo some milder days and rain. But this is all part of the bigger picture that is edging towards a strengthening of the blocking signal, the atlantic being pushed back, and the jet heading south underneath wave break potential in Xmas week.

So - no change from last night's prognosis. What would be good to see next would be an ECM run later or tomorrow that flags this setup more clearly at 240h. FI we know is unreliable, but I'll feel better when I see ECM latch onto it for the first time.

[Climate Man]

32 minutes ago, danm said:

Yep and 1987 also had the advantage of occurring in the depths of winter rather than the start of meteorological Spring, as was the case in 2018. 

Missed it, was living in central Wales and it was relatively balmy.

[Ali1977]

10 minutes ago, Climate Man said:

Missed it, was living in central Wales and it was relatively balmy.

Not that balmy , look at those -10c Max’s over Belgium 

Edited December 8, 2020 by Ali1977