Model Output Discussion - early October

[Methuselah]

From today's GEFS 00Z ensembles, I'd guess that a typical (if a tad wetter than average?) couple of weeks' Autumn weather is in store:

   

   

Not to worry, though -- winter doesn't start for another 5 weeks!

Edited October 26, 2019 by Ed Stone

[Frosty.]

The GEFS 0z mean is advertising a generally unsettled / cyclonic outlook with temperatures slightly  below average, especially for scotland but a bit milder at times further south and hints of a northwest / southeast split later with height rises to the SE.

Edited October 26, 2019 by JON SNOW

[mb018538]

2 hours ago, IDO said:

The temporary wave pattern was from a one-off event and wasn't really heralding a pattern change. It was a case how much cold could we get from it? As the pattern flattened in the Pacific region it was going to fire up the Atlantic for a while.

We are back to that en passe where there is little forcing from the lower regions and no sign of the PV getting its act together. So a period of quasi-zonality with the UK at the wrong latitude to avoid the nasty stuff. The GEFS are on a similar vein right out to the dark recesses of FI.

So we await the formation of the PV to see what sort of Nov/Dec we have in store. ATM no sign of the persistent Atlantic wave/ridge that dominated our weather for many months this year.

 

No sign of the PV getting its act together? It’s forecast to be miles above normal as we go Into November? I don’t get your point there!

[johnholmes]

3 hours ago, shaky said:

Its the same thing year in year out!!the 18z ensembles were really cold last night but the control and op were well away from that main cold bunch and a few thought its a mild outlier but you wake up this morning and all the other members have joined the control and op and turn it much milder!!its frustrating cos if it was vice versa it would never happen lol!!so frustrating!!

So many of you in the far reaches are following run to run. It will 90% of the time show these variations. Try comparing the same run to get a better idea of what may happen. I know I sound like a stuck record but it is more reliable than run to run at longer time intervals.

[IDO]

5 minutes ago, mb018538 said:

No sign of the PV getting its act together? It’s forecast to be miles above normal as we go Into November? I don’t get your point there!

...the trop PV.

The strat-trop link is not really there at the moment? I am more interested in the trop aspects as the strat down-welling effects take time to manifest on the ground, if indeed what is predicted even materialises in the grander schemes! 

[feb1991blizzard]

Really not all that far away from a frigid Easterly, these runs are popping up all the time.

[knocker]

The front still appears to be the Wash > Bristol > north of Cornwall

[Methuselah]

I'd say that things look rather good, here at T+294; but, as to how things pan-out in the longer term, who knows? Way too many variables...?

   

[fromey]

Has this been discussed yet?? Sorry if it has.

just popped up on my news feed

[damianslaw]

Looking through the jetstream profile forecasts - the output is showing a predominantly southerly tracking one, aligned NW-SE which would suggest diving low pressure systems over the UK probably more to our west, with some form of blocking to the north or NE holding sway, these could change, but does align with the models at the moment, with next week's mid week low pressure system forecast to move in from the SW/W on wednesday and thursday, collapsing in on itself over the UK and forced to retreat SE, with perhaps showery cool conditions from the NW thereafter, the forcing appears NW-SE aligned.

Looking longer term - no sign of anything especially settled as we enter November, all rather typically autumnal and very seasonal.

[MATTWOLVES 3]

Not a great set of ensembles from the 6z....much more runs above than below over all! Much to early for me to be concerned, I'd rather see these ensembles falling in around a months time, than falling right now... The mean just about remains above the 0C mark. 

[Methuselah]

Nowt too much in the way of ensemble-scatter apparent in today's 06Zs, so I guess the GFS Operational's evolution can (in light of the BBC's monthly) be taken somewhat seriously: HP dominant to our NW, N & NE, while LPs lurk menacingly to the S, SW & W?

                                      

The 06Z ensembles:   

                                    

Things could be about to get interesting?

Edited October 26, 2019 by Ed Stone

[northwestsnow]

35 minutes ago, Mattwolves said:

Not a great set of ensembles from the 6z....much more runs above than below over all! Much to early for me to be concerned, I'd rather see these ensembles falling in around a months time, than falling right now... The mean just about remains above the 0C mark. 

They look wet for London so i dread to think what they will look like for the north west!

[Ross90]

Central Scotland looks fairly similar.A couple of clear days and a couple of quite wet looking days.

[Froze were the Days]

Well the projected cooler and drier spell next week looks like it is getting shorter lived by the run on the ecm...low pressure dominant near the country come the start of November, why shouldn't we be surprised?

Edited October 26, 2019 by Froze were the Days

[SMU]

Afternoon All-

A couple of topsy turvy couple of days where the models moved away from a persistent cold spell to a something shorter- interupted by something milder again-

However the chase continues back again around 150 onwards as the jet dives SSE in the atlantic again - This combined with residual heights to the north will cause systems to slide ESE-

The 06z NAVGEM paints the best picture...

 144 then 180

 

[knocker]

Marked drop in temp behind the front as it continues to move south east

[fromey]

9 minutes ago, knocker said:

Marked drop in temp behind the front as it continues to move south east

You ain’t kidding!!

[SMU]

12z GFS continues ( as does the ICON ) with pressure in situ over Greenland-

Despite the ramping up of the vortex this area remains locked into higher than ave pressure-

We dont always need a stella high pressure - just a steering high is good enough....

[blizzard81]

Liking the way the low stalls in our vicinity with the high getting sucked back into the Atlantic instead of meandering into Iberia. Reminds me of of early Nov 2009 and 1962.

[Methuselah]

Now this is much better -- I think...WAA up through Eastern Europe and Western Russia, instead of up through the UK!

   

[swfc]

Way in fi we get an easterly.not great 850s but hey ho.look at the PV and real cold heading into the USA

[mb018538]

47 minutes ago, Steve Murr said:

12z GFS continues ( as does the ICON ) with pressure in situ over Greenland-

Despite the ramping up of the vortex this area remains locked into higher than ave pressure-

We dont always need a stella high pressure - just a steering high is good enough....

Think you are flogging a dead horse here Steve....it was looking good a few days ago, but we’ve seen the usual correction to full steam zonal, and that’s what we’re going to get for a while.

[summer blizzard]

6 minutes ago, mb018538 said:

Think you are flogging a dead horse here Steve....it was looking good a few days ago, but we’ve seen the usual correction to full steam zonal, and that’s what we’re going to get for a while.

Although i don't always agree with Steve's 'favourable' interpretation of events in this case i am with him. Negatively tilted troughs (even if they are introducing milder air in this case) are not normal and certainly not a classically zonal pattern. 

A classically zonal chart is more like this one with the low parked off the NW of Scotland and rain and gales with a W/SW wind.

[mb018538]

5 minutes ago, summer blizzard said:

Although i don't always agree with Steve's 'favourable' interpretation of events in this case i am with him. Negatively tilted troughs (even if they are introducing milder air in this case) are not normal and certainly not a classically zonal pattern. 

A classically zonal chart is more like this one with the low parked off the NW of Scotland and rain and gales with a W/SW wind.

I will agree with you there - it’s not classic zonality as we know it, but the subtropical high is retracted and lower heights dominate to the north. It’s zonal enough, fairly typical for autumn.