Model Output Discussion - Into February

[Stuie]

5 hours ago, tight isobar said:

Wel bone picking it’ is- but the gefs/ eps doesn’t take much index pattern looking!! The draw is there .. via top Scandinavian blocking signature!. These being the suite 12z format without 2m- and raw 850hpa!. Because it’s pointless, as an evolutionary trait/ prognosis!.. it’s purposefully worthy though!- as the structure of shallow = deep minamal plots can/ WILL mean vast difference.... and they are even out to day 5- not stone set!!!.. let me say THIS again.... a draw of worthwhile cold is still well open..... and maybe your eyes will be as we watch the HP fruition !!

It does want to lose the blocking strength signal fairly quickly,  It may just be that the signal like you are showing is ridiculously strong and that HP will remain albeit not around 1040

 

[feb1991blizzard]

4 minutes ago, KTtom said:

Hmm not sure... I spot a Norwegian Shortwave!

yes - tracked bad, just as -20c was poised and a perfectly aligned Atlantic trough was gonna be undercut, run still looks very white to me.

[Guest]

ECMWF 00z at 168hrs looks positively spring like

[sunnijim]

Slowly, slowly, catchy monkey?

I might be wrong but I think this High pressure system is the same feature that started life over Scandanavia a couple of weeks ago?

It backed west to end up to our SW, is on the move and intensifying over us and wants to eventually head 'home'?

We shall see, I know the Azores High likes to play that game, can a Scandanavian High play it the same.

Sorry if this sounds desperate and unscientific!

[Weather-history]

24 minutes ago, Tidal Wave said:

ECMWF 00z at 168hrs looks positively spring like

"Looks" is the key word here

Infact that chart is at midnight and hints at a touch of a frost

It is currently milder now than what that chart is predicting for a week away.  

[Ali1977]

Does anyone know if the GEFS mean still had a SSW? Hoping not to lose that signal 

[Guest]

22 minutes ago, Weather-history said:

"Looks" is the key word here

Infact that chart is at midnight and hints at a touch of a frost

It is currently milder now than what that chart is predicting for a week away.  

Hence the terminology I used!

Bit of sunshine by day will feel pleasant enough I imagine though.

Edited February 4, 2023 by Guest

[Blessed Weather]

33 minutes ago, Ali1977 said:

Does anyone know if the GEFS mean still had a SSW? Hoping not to lose that signal 

From what I can see the GEFS mean hasn't been showing a reversal of zonal mean winds at 10hPa (i.e. a technical SSW) over the last few days. But what is interesting is that when comparing the 0Z run over the period, the mean has been getting closer to a SSW with every run. This morning getting very, very close. Weatheriscool estimate the chances of a SSW now 48%.

Quite a few ensemble members (green) going for a reversal:

Source: http://weatheriscool.com/

 

Edited February 4, 2023 by Blessed Weather
Edit: Ensemble scatter chart added.

[SLEETY]

Ecm was a tad on the mild side compared to the other runs in the ensemble pack, does it most the time so not surprised anymore. 

Edited February 4, 2023 by SLEETY

[Vikos]

16 minutes ago, Blessed Weather said:

From what I can see the GEFS mean hasn't been showing a reversal of zonal mean winds at 10hPa (i.e. a technical SSW) over the last few days. But what is interesting is that when comparing the 0Z run over the period, the mean has been getting closer to a SSW with every run. This morning getting very, very close. Weatheriscool estimate the chances of a SSW now 48%.

Quite a few ensemble members (green) going for a reversal:

Source: http://weatheriscool.com/

 

Was 61% yesterday…

[Blessed Weather]

1 hour ago, Vikos said:

Was 61% yesterday…

Yes, despite today's GEFS mean edging marginally closer to a reversal than yesterday's mean. I'm guessing, but I wonder if the reason is because the 'mean' is basically an 'average' of all members zonal wind speed, whilst the % chance of a SSW is simply calculated by how 'many' members show a reversal? So yesterday 21 members went for a reversal, today 15 members, but today's 15 are going for a more significant reversal?

If anyone from weatheriscool is reading this, an insight into how the % chance is calculated would be gratefully received.

Edited February 4, 2023 by Blessed Weather
typo

[ribster]

54 minutes ago, Tidal Wave said:

Hence the terminology I used!

Bit of sunshine by day will feel pleasant enough I imagine though.

Terminology - the body of terms used with a particular technical application in a subject of study, profession, etc.

[joggs]

1 hour ago, Ali1977 said:

Does anyone know if the GEFS mean still had a SSW? Hoping not to lose that signal 

I hope it loses the signal tbh. I don't want an increased chance of a cold start to spring.

[Ali1977]

24 minutes ago, joggs said:

I hope it loses the signal tbh. I don't want an increased chance of a cold start to spring.

With you if any fallout would be mid March onwards, early March can still be good for snow at all levels though. 
 

And spring is only good if it’s unusually warm!! 

[mushymanrob]

2 hours ago, Tidal Wave said:

ECMWF 00z at 168hrs looks positively spring like

Dont be fooled.... the "uppers" might suggest mild but at the surface the cold is likely to linger. That chart suggests an inversion to me, so remaining cold and grey at the surface as the milder air overrides the surface cold.

[alexisj9]

3 hours ago, KTtom said:

Ironic or just blumin aggrivating, but just as we had a chance of pressure rise to the north east, the core of the PV decides to leave Greenland for the first time this winter and relocate there! 

 

To be honest, that's what I've been expecting.. it will get better than on this chart though. Another northerly doesn't float my boat, but it should be a better one.

[E17boy]

Morning peeps,

Hope you all are keeping well. Oh winter where are we going with you?? A benign cloudy start here in North East London Walthamstow this morning. At the moment we seem to be stuck with the weather nothing much seems to be happening. Apart from some possible rain tonight here next week looks the same although there are hints of cooler nights where skies clear and some possible frost. 
 

I posted a week ago saying there was faint writing written on the walls telling the story for what we have got left of winter. Nothing has changed from my eyes a week on I am still not yet seeing any convincing model output for any change to something wintry at least for another week yet.

Whilst we are now alas pinning all our hopes and faith that a SSW can come and rescue us, which may save winter. However a great deal of caution is still required, yes we may end up getting a SSW but that does not necessarily mean it will always play in favour for our island. I really hope in my heart that something down the line will now have to give and at least we can get a taster of something from the east.  The worrying thing now on the back of our minds is that the daylight hours are getting longer and so is the suns strength. Something needs to happen soon to survive these factors which will eventually decrease the chances of any sustained cold.  Here hoping the coming days a helping hand from the models will listen to our cries.

have a great day all

regards

THE TIME IS GETTING CLISER TO MAKE OR BREAK FOR WINTER

[minus10]

Gfs 6z keeping us on the cold side at day 7 with that cold pool...

 

[Ali1977]

Much hotter up too on this run 

Edited February 4, 2023 by Ali1977

[Vikos]

what ever is left… go to hell!

[Cambrian]

Next few days a chilly anticyclone provides a comfortable early February place to sit back and await the further ramifications of changes in stratospheric wellness. In the meantime, there’s already a great deal going on in the troposphere, as shown in the 0z ECM ensemble mean charts. 

At the moment, we have our high, building in beautifully from the southwest, handsome looking thing by day 2, though never quite gets far enough north to make it really exciting, some reasonable frosts for many. The vast bulk of the tropospheric PV at that stage is centred with vivid strength Baffin way, from northeast Canada, extending to cover much of Greenland. No real vortex at all over western Siberia, or for, - hey (American nature documentary narrator voice, you know the guy) look at this cute little critter, he’s a Svalbard reindeer, called Isak. 

   

It’s only a temporary reprieve for Isak, though, as by day 4, the PV is on the move, through Svalbard, extending into the Barents Sea. It’s this move that helps to put the southeastward squeeze on our high, the eastward transfer of the PV complete by day 6. 

By day 8, the real power of the PV is very much on the Siberian side, linking through to Isak. For us at this stage, little has happened. The Atlantic trough remains south of Greenland, with a gentle western European maritimes feed into the UK and Ireland. Still anticyclonic,  largely dry, chilly nights, close to average overall. 

  

By day 10, we get a truer westerly feed, but this is only transitional, as by day 12, there’s a very definite movement east of the trough, some build of heights north from the mid Atlantic towards Greenland, so a smart reversal of the amplification profile, with low pressure sitting between Iceland and Scotland, heights much lower by then for the UK and Ireland.  That’s a fairly cold looking feed for us from the northwest, but originating from much further up north, close to you know who! Plenty of scope for cold trough developments by then, systems easily able to wrap in cold air from the Arctic, the mean wind direction steadily working around the dial to the north.

The Siberian PV is still very much in the driving seat, and the Atlantic by then is returning to even fuller quiescence, so if we get the trough to transfer fully east into Scandinavia just as we realise the effects of any wellings, splits, displacements, obliterations, etc., then things might well already be aligned very favourably for a quick transition to a much colder pattern, that won’t be getting shifted away any time fast. 

[Allseasons-Si]

A sign of things to come,...maybe!!!

control just after day ten.

[Ali1977]

5 minutes ago, Allseasons-si said:

A sign of things to come,...maybe!!!

control just after day ten.

There are several ENS showing this set up too
 

A few here 

Edited February 4, 2023 by Ali1977

[bluearmy]

4 hours ago, Ali1977 said:

Does anyone know if the GEFS mean still had a SSW? Hoping not to lose that signal 

Hasn’t yet on the mean as bossed weathers post below.  Eps mean is still just reversed post T312

4 hours ago, Blessed Weather said:

From what I can see the GEFS mean hasn't been showing a reversal of zonal mean winds at 10hPa (i.e. a technical SSW) over the last few days. But what is interesting is that when comparing the 0Z run over the period, the mean has been getting closer to a SSW with every run. This morning getting very, very close. Weatheriscool estimate the chances of a SSW now 48%.

Quite a few ensemble members (green) going for a reversal:

Source: http://weatheriscool.com/

 

 

3 hours ago, Blessed Weather said:

Yes, despite today's GEFS mean edging marginally closer to a reversal than yesterday's mean. I'm guessing, but I wonder if the reason is because the 'mean' is basically an 'average' of all members zonal wind speed, whilst the % chance of a SSW is simply calculated by how 'many' members show a reversal? So yesterday 21 members went for a reversal, today 15 members, but today's 15 are going for a more significant reversal?

If anyone from weatheriscool is reading this, an insight into how the % chance is calculated would be gratefully received.

Straight number of members that reverse as a percentage of 30 members 

[blizzard81]

15 hours ago, blizzard81 said:

Ecm mean looks more blocked from the east compared to the morning suite. I expect debilt to be colder. Less pressure from the north west. 

The debilt ens look meh this morning.