Model output discussion - Winter approaches

[nick sussex]

Tonight’s latest mood swing from the ECM is to bring back the easterly tease or at least the battle of blocking with the angry looking troughing to the nw which is being fed by the main PV further north .

The GFS wants to see a similar battle but upstream it has a developing shortwave out of kilter with the Euros so it’s evolution might be questionable .

The UKMO performs a backtrack of sorts , less progressive with the troughing to the nw .

You can perform an exit poll type scenario from early on.

The baseline is how far energy gets east towards Iceland at days 5 and 6 . So for newbies . Draw a line ne, west of Ireland upto eastern Greenland ,  the further west you see those deeper low heights the compound effect moving forward will increase chances for something colder .

And a sharper looking trough means more energy is heading se . The round base of the troughing is an easy guide to eastwards momentum .

The key thing in these scenarios is to get energy underneath any lobe of high pressure to feed lower pressure over Southern Europe .

Overall tonight a bit more potential for coldies , several possible scenarios on the table if the cards fall nicely . However we could also easily see a stalemate situation with the troughing hanging over the UK .

 

Edited November 21, 2020 by nick sussex

[Tim Bland]

Fair to say ECM was a pressure outlier

[SMU]

GFS through 96 has wedged a bit more high pressure in the gap squeezing NE which will mean a smoother transition to a blocked scenario- The key to any easterly will be the flow allignement of the cold upper pool at 168.

ECM was westerly which allows the pool to move West then NW escaping the UK- we need the allignment SSW really !

Note the better amplitude of the jet 114 V 120 & the scandi arm directed more towards the UK

Edited November 21, 2020 by Steve Murr

[sheikhy]

2 minutes ago, Steve Murr said:

GFS through 96 has wedged a bit more high pressure in the gap squeezing NE which will mean a smoother transition to a blocked scenario- The key to any easterly will be the flow allignement of the cold upper pool at 168.

ECM was westerly which allows the pool to move West then NW escaping the UK- we need the allignment SSW really !

Brilliant update steve!!!keep it going!!!also i think another thing to watch out for is that little shortwave exiting the usa at 144 hours!!will it join the ecm and vanish it or will it still be there as it showed on the 12z gfs?

[Allseasons-Si]

9 minutes ago, sheikhy said:

Brilliant update steve!!!keep it going!!!also i think another thing to watch out for is that little shortwave exiting the usa at 144 hours!!will it join the ecm and vanish it or will it still be there as it showed on the 12z gfs?

You need that little shortwave to cause more amplification upstream as was shown on the 12z gfs,that's why the ECM wasn't a great run because it wasn't there,not so much there on this latest run.

[Eskimo]

Mesmerising stuff if you like benign weather.

Edited November 21, 2020 by PerfectStorm

[sheikhy]

1 minute ago, Allseasons-si said:

You need that little shortwave to cause more amplification upstream as was shown on the 12z gfs,that's why the ECM wasn't a great run because it wasn't there,not so much there on this latest run.

Its joined the ecm in that sense then!!lets see what happens to the scandi high now!!!

[Griff]

No doubt plenty of teasing to be seen in FI, but looking beyond a week for anything other than a trend seems speculative. Last weekend was emotional and its only November, this weekend also. Lots of hope currently for the start of December.  

[Eskimo]

Goodnight! 

[nick sussex]

The GFS started less progressive then went downhill. It never sharpens up the troughing sufficiently so just turns into a recipe for insomnia .

As long as you maintain those lower heights over Southern Europe then the displaced Azores high can’t move into that area . If the limpet troughing to the nw sharpens up more then things could still improve on the cold front .

Tonights verdict .

Holding pattern waiting for more drama to ensue ! 

[Allseasons-Si]

This is not a moan but do you know what...

scap this phantom eastery because it's not going to happen,last week it was showing the same synoptic forecast only for it to go bang and the easterly has gone

let's hit the....

..button and get a better pattern rolling

and as i said all of that,the gfs does this...

this is better in my opinion,lets get some action rolling because i am getting bored of chasing easterlies

watch the eastery verify now

 

[Griff]

You have to laugh though because in the depths of fi this happens... 

Background signals and chocolate teapots.... 

Edited November 21, 2020 by Griff

[Tim Bland]

Agreed..Happy to reset if it leads to this, much more exciting! Would rather be doing the north a bit, south a bit, discussion over warm sectors etc and gamble on high stake sliders than pray for a flurry from an easterly that never quite makes it! 

Edited November 21, 2020 by Tim Bland

[Allseasons-Si]

BOOM!!!

that's more like it.

[Griff]

Just now, Allseasons-si said:

BOOM!!!

that's more like it.

We're fools for even dreaming

[Allseasons-Si]

Just now, Griff said:

We're fools for even dreaming

It's the silly hour

besides,some of the 12z gefs ens was showing this. 

[bluearmy]

The pub run is chucking a little chunk of vortex into the n flow in fi .....

[Griff]

2 minutes ago, bluearmy said:

The pub run is chucking a little chunk of vortex into the n flow in fi .....

Guaranteed!  

 

Edited November 21, 2020 by Griff

[Allseasons-Si]

"Forum meltdown alert"

polar low incoming...

[Griff]

Well it continues the theme of suggesting lows into southern Europe and shaking away the heights

[booferking]

2 minutes ago, Allseasons-si said:

"Forum meltdown alert"

polar low incoming...

Lol 510 dam wrapped round it.

[Tim Bland]

24 minutes ago, PerfectStorm said:

Goodnight! 

If this run is boring you... you need to get a new hobby!

Edited November 21, 2020 by Tim Bland

[BLAST FROM THE PAST]

18z looking good to me, if we get Atlantic to push through, which I believe will occur, we want it to develop like the 18z .  Has chances imo and certainly brings some weather of note and interest.

The high will collapse on the run but it’ll be a slow cold one...

 BFTP

Edited November 21, 2020 by BLAST FROM THE PAST

[Zak M]

Pub run is going bonkers as usual...nothing to see here!

It's even having a go at another shot too.

Some very cold 850hpa temps - uppers in excess of -16c near SE Iceland and NW Scotland..

   

[Daniel*]

14 minutes ago, Allseasons-si said:

"Forum meltdown alert"

polar low incoming...

Not hugely dissimilar to pattern what brought significant wintry weather to many in first half of December 2017. We have mentioned some similarities to that month, both La Niña winters very similar strength too.