Model Output Discussion - early October

[shaky]

Pretty big changes early on on gfs 12z!rain band further north and west for saturday!!looks so much better at 120 hours though if you like cold!!the orientation of the high is much better in the atlantic!

Edited October 23, 2019 by shaky

[SMU]

UKMO & GFS 12z out

UKMO continues on its progressive cold solution & GFS on the same hymn sheet after 72 hours of nonsence ensembles.

NB the 'node' of greenland pressure indicating that a quick sweep through is unlikely

GFS

[Jordan S]

Gfs having a more Gem and Icon look to things with the area of low pressure coming in on Friday not developing as much thus less hill snow on the northern flank and winds are not as strong as previously shown.. 

but makes more of the rainfall and has a wave feature strung out for Friday night into Saturday giving some area's continuous rainfall for 12 to 24 hours with the back end of the front developing into a modest area of low pressure during Saturday mabye more undercutting with that on the northern side only finally clearing later Saturday.. looks like this will *probably* be the most likely outcome now but not necessarily as its still 2 days away. 

A closer look.. 

Rain will likely be the main issue with this the winds and especially Hill snow a lesser issue although still very windy in the south with gales in places perhaps minor changes are expected so not nailed on just yet..

Edited October 23, 2019 by jordan smith

[Iceaxecrampon]

12z 

GFS giving potential 24hrs of Rain Midlands -  N England - heads up Cumbria.

 

Edited October 23, 2019 by Iceaxecrampon

[Frosty.]

25 minutes ago, shaky said:

looks so much better at 120 hours though if you like cold!!the orientation of the high is much better in the atlantic!

Indeed, couldn't agree more, looks good with deeper cold uppers (850's) digging further south!

Edited October 23, 2019 by JON SNOW

[tight isobar]

12 minutes ago, jordan smith said:

Gfs having a more Gem and Icon look to things with the area of low pressure coming in on Friday not developing as much thus less hill snow on the northern flank and winds are not as strong as previously shown.. 

but makes more of the rainfall and has a wave feature strung out for Friday night into Saturday giving some area continuous rainfall for hours on end with the back end of the front developing into a modest area of low pressure during Saturday mabye more undercutting with that on the northern side only finally clearing later Saturday.. looks like this will *probably* be the most likely outcome now.

Rain will be the main issue with this the winds and especially Hill snow a lesser issue although still very windy in the south with gales in places perhaps. 

Let's be brutally honest..

I'm quite sure most knew...at such a stage...And cliff like set up snow was 'never' going to be an issue..away from the highest elevation s..

 

Anyway...I cannot help but keep thinking...this will be the season of the cut through chanel low!!

#just a hunch^^^

 

It's distracting me 'somewhat'=

With given past n'present!!..

Synoptics/evolution s.

 

 

Edited October 23, 2019 by tight isobar

[Mike Poole]

GFS T156:

Scrappy Doo vortex!  Been a while since we've seen one of those!  

Better predictor of a cold winter than the OPI. Honest. 

[Radiating Dendrite]

1 minute ago, Mike Poole said:

GFS T156:

Scrappy Doo vortex!  Been a while since we've seen one of those!  

Better predictor of a cold winter than the OPI. Honest. 

Yes, nice to see it over Siberia - hopefully it decides to holiday there all winter!

[Jordan S]

4 minutes ago, tight isobar said:

Let's be brutally honest..

I'm quite sure most knew...at such a stage...And cliff like set up snow was 'never' going to be an issue..away from the highest evelations!!

 

Anyway...I cannot help but keep thinking...this will be the season of the cut through chanel low!!..

 

It's distracting me 'somewhat'=

With given past n'present!!..

 

 

Was just pointing it out that's all and wanted to make sure some didn't think it was going to be a significant thing for northern areas.. Away from the highest peaks perhaps.. like you say.

Edited October 23, 2019 by jordan smith

[Methuselah]

Much more seasonal Autumn weather -- even some winry stuff in hilly Eastern parts?

   

Baby steps...?

[SMU]

That poor vortex being ushered NE out if Canada...

There could be a clear reason why this season- will update the winter thread later...

GFS192

 

[ICE COLD]

Gfs 12z at T192 looking decent . 

 

Edit - SM beat me to it 

Edited October 23, 2019 by ICE COLD

[Allseasons-Si]

Everything looks to have backed further southwest a few hundred miles esp NW Europe as in terms of synoptics.

[booferking]

Here we go look North...

[tight isobar]

A sight for the eyes indeed..And we are now into November...a much more feasible part for interest!!

 

And even with the given profile/synop..

We could be seriously talking much more notable upper air spreads...making in roads...into north western Europe!!

 

It's all so tempting looking right now!!!!

[feb1991blizzard]

The high is too rounded at 240 now, you really could do with sharper ridging right into the pole to get some really frigid air and snow chances.

[booferking]

22 minutes ago, feb1991blizzard said:

The high is too rounded at 240 now, you really could do with sharper ridging right into the pole to get some really frigid air and snow chances.

Yea 216hr looked great but the trigger low failed this time.

[feb1991blizzard]

2 minutes ago, booferking said:

Yea 216hr looked great but the trigger low failed this time.

 

Back end about to go gold again but not cold enough and just fleeting N'ly.

[Mike Poole]

Key as we move towards winter is the degree of connectedness between the tropospheric and stratospheric vortices as the strat vortex develops in intensity.  Especially so in this solar minimum - the solar minimum may affect our winter weather not because of the slight reduction in solar radiation per se (which really is a minescule reduction) but, it seems, by a mechanism that leads to a more meridional jetstream (as we seem to be seeing now).

So the interplay between the trop and strat vortices seems particularly important this year, and to visualise the starting point (if now is a good time to call a start to the run up to winter) I really like this graphic from stratobserve.com :

This reduces the strat vortex to an approximated ellipse at each level of the atmosphere, yellow at top (1mb) to dark orange (150mb).  Then compare the trop vortex from the  Meteociel plot (from GFS at same time):

Notice the purples in about the spot the orangier ellipses converge on.  Between them, the two plots give an idea of the 3D nature of what is going on, and it will be interesting to see how this evolves in the coming weeks and months, so I will post this from time to time.  

Edited October 23, 2019 by Mike Poole

[tight isobar]

Jet profile...as we enter November!

 

I've snapped the stills for purpose..

As Atlantic warmth gets ommphed into Greenland...And into the pole..

With the purposed arching jet around the block...

 

Anyone remember how we got started 2010...with similar modelling around this- point beginning!

 

 

!!!!!

 

 

Edited October 23, 2019 by tight isobar

[Mike Poole]

GEM 12z a good evolution from a cold perspective, run seems stuck, so here's the charts at T228:

Greenland remaining open for height rises, cold pushing towards the UK, for me the first is the more important at this early stage...

GEFS, well most members below T850 of 0C for a period in the semi-reliable, even in my location in the south!

Edited October 23, 2019 by Mike Poole

[Beanz]

22 minutes ago, tight isobar said:

Anyone remember how we got started 2010...with similar modelling around this- point beginning

 

Yes, I was debating the same idea actually.  

Let’s see how it evolves, it’s certainly a very interesting comparison at the moment 

[Mucka]

The coming rain across central UK is the main story but looking at long term prospects the signal is currently for negative pressure anomalies to our South and positive to our West through first half of Nov which means it will likely be cooler than average, not withstanding there could still be some milder days, but with greater than average chances of polar air sinking into the mid latitudes at times.

 

Edited October 23, 2019 by Mucka

[Methuselah]

47 minutes ago, feb1991blizzard said:

Back end about to go gold again but not cold enough and just fleeting N'ly.

I don't know about going GOLD, feb, but if all the cards fall right, it could even go platinum!

   

[tight isobar]

Just very quickly...where is shortwave steve!???