Model Output Discussion - Into Autumn 2019.

[feb1991blizzard]

21 minutes ago, prolongedSnowLover said:

Looks like the GFS has jumped on the EC 0z signal with a potent Nottherly! When’s the last time there was significant snow in the UK in September ?

 

1919.

[knocker]

A good illustration of the deconstruction of the upstream trough creating a cutoff upper low and the subsequent energy flows 24 hours later with the very strong thermal gradient just north of the UK.

And where this goes from here becomes quite important with the trough/lobe to the NE being quite influential

Edited September 9, 2019 by knocker

[Frosty.]

Well the Ecm 12z operational is a huge upgrade longer term compared to the 0z with high pressure dominating and becoming very warm across southern uk. The GEFS 12z mean also looks dominated by anticyclonic weather from later this week onwards into late september!...perfick

 

 

Edited September 9, 2019 by JON SNOW

[shaky]

Much better ecm this evening compared to 00z run!!sunny and warm from friday onwards and dry till the end of the run!!gfs 12z seems to have gone off  on one when looking at the ensembles!!expect an improvement on the 18z!!

[Singularity]

  

Sometimes cut-off lows can produce some of the wackiest weather patterns at short notice, if the upstream pattern remains amplified. 

You can really see here, knowing how differently GFS and ECM unfold thereafter, how even the slightest continued connection to the polar jet (the 'nose' formed by the 1020 mb line to the WNW of the UK in the ECM chart) is able to prevent the high pressure across the UK from retrograding to the W/NW of the UK.

We've seen that kind of residual connection deny us many a potential wintry northerly in the cold season.

For what it's worth, ICON 12z is close to the UKMO 12z, while GEM sits between UKMO and ECM.

GEFS and EPS continue to favour the UKMO/ICON 12z or GEM/ECM 12z style outcomes. Even so, I'm keeping an open mind to the cut-off low potential; not going to sit here naively presuming that it will be pleasantly warm during my week off... .

[shaky]

Fantastic ecm mean this evening!!very rarely you see pressure rise on the mean the way it is shown this evening between 192 and 240 hours!!1025mb high slap bang over the uk!!

[I remember Atlantic 252]

43 minutes ago, shaky said:

Much better ecm this evening compared to 00z run!!sunny and warm from friday onwards and dry till the end of the run!!gfs 12z seems to have gone off  on one when looking at the ensembles!!expect an improvement on the 18z!!

Aye, EC keeps the filth away, still not out of the woods though with a potential vile N'ly

[Frosty.]

If you don't like increasingly warm anticyclonic Ecm 12z ensemble means, look away now!...for everyone else..feast your eyes on these beauties!!

[knocker]

The latest EC46 update between 20th Sept and the 12th October is still pretty good. A waning high pressure influence over the period  and thus trending towards the usual N/S split but temps remaining above average and very dry apart from the far NW at first and then later more rain in western areas without going overboard. The southern half of the country could well be in south westerly zephyrs which bodes well for the winter.

Edited September 10, 2019 by knocker

[knocker]

The North Atlantic 500mb and surface analysis for midnight

Ex hurricane Dorian and TS Gabrielle are currently scooting up the western flank of the ridge and fronts from the former will bring rain and strengthening winds into N. Ireland and western Scotland by 1600  Elsewhere it will generally be a sunny day with some broken cloud and the odd shower may bubble up in central and eastern areas of England.

The rain will quickly track south east through this evening and overnight, fragmenting as it gets further south, with heavy pulses on the windward side of mountainous areas in Scotland and north west England. Heavy showers will follow in the wake of the fronts and it will be quite a windy night

The cold front should clear the south coast by early afternoon Wednesday leaving much of England and Wales with sunny intervals but still some heavy showers further north, courtesy of a couple of troughs embedded in the circulation

But as can be seen the remnants of Gabrielle are tracking north east and they will bring rain and squally winds on Thursday, principally in northern regions but then further south as the cold front moves through.

By Friday the inclement weather has departed and the subtropical high has gained more traction so a much better day, dry with sunny intervals, But there are developments in the western atlantic that have been discussed in previous posts and another surface low has arrived south of Greenland.

By Saturday the upper trough in the west has disrupted creating a cut off upper low whilst the surface low deepens and tracks north east to Iceland with the associated fronts sweeping across the north of the country around the high cell bringing rain and strong winds with them

 

[knocker]

I think another couple of days will suffice vis the details for the moment

[ItNeverSnowsInWindsor]

Not a bad start to autumn for some if this chart proves to verify! Like proper autumn should be.

 

[Methuselah]

Well, well, well -- talk of September snow did have me thinking. Until looking at the ensembles!

    

    

Still, it's always better than being whacked in the face with a wet haddock!

[knocker]

A general overview of the ecm in the 5-10 period would be the energy dispersal around the amplifying and durable subtropical high and thus the adjustment of position and  orientation of the surface high cell Dry with temps a tad above average but an increasing diurnal variation

[shaky]

Much improved 00z ecm again this morning!!no northerly at all and warm and sunny all the way through!!you can see gfs do that slow backtrack again that it normally does!!it slowly pushing that northerly further east when you compare the last few runs for similar time frames!!ukmo is hot like the 12z yesterday!!

[mb018538]

Does anyone have the link to the ECM individual ensemble charts? I’ve forgotten it! I think it’s a US based site that gives 2m temps etc? Much appreciated!

[northwestsnow]

The Autumn fishing season looks primed to kick off with some settled weather , can't wait to get my rod out and hit the bank friday morning

EC might provide some warm-ish days and cooler nights ?

 

[MATTWOLVES 3]

3 minutes ago, northwestsnow said:

The Autumn fishing season looks primed to kick off with some settled weather , can't wait to get my rod out and hit the bank friday morning

EC might provide some warm-ish days and cooler nights ?

 

Sorry NWS I had to read the first part of your post several times, it made me laugh that much.. And yes things looking very peachy... Just check out ECM at day 10!!! Possibly very warm uppers encroaching from the South. 

[shaky]

Aaaaaand the 06z gfs has completely put the northerly in the bin now and it looks more like the ecm! !amazing output for the time of year!!

 

[Methuselah]

What a lovely chart!  

[ItNeverSnowsInWindsor]

GFS 6z looks a bit of a warm outlier..

 

[Don]

8 hours ago, knocker said:

The latest EC46 update between 20th Sept and the 12th October is still pretty good. A waning high pressure influence over the period  and thus trending towards the usual N/S split but temps remaining above average and very dry apart from the far NW at first and then later more rain in western areas without going overboard. The southern half of the country could well be in south westerly zephyrs which bodes well for the winter.

Erm, not for likes of me it doesn't but each to their own of course!  Personally not liking the way this September is shaping up and does not bode well for winter.....

[northwestsnow]

7 minutes ago, Don said:

Erm, not for likes of me it doesn't but each to their own of course!  Personally not liking the way this September is shaping up and does not bode well for winter.....

Think you might be thinking a bit far ahead Don

[Don]

5 minutes ago, northwestsnow said:

Think you might be thinking a bit far ahead Don

Maybe, maybe not.  It would be better from my perspective to see how the rest of the month actually pans out mind!

[weirpig]

Just now, Don said:

Maybe, maybe not.  It would be better from my perspective to see how the rest of the month actually pans out mind!

Why  are you making some correlation to the month of September?.