Model output discussion - summer rolls on

[Frosty.]

Feeling cold  towards the end of the Gfs 6z operational.☺

[Frosty.]

Looking at the Gfs 12z operational...summer won't be rolling on beyond next midweek, it looks pretty autumnal beyond that, especially further north..so unless the gfs is very wrong, it will soon be time for a new thread!!

[Mike Poole]

10 minutes ago, Frosty. said:

Looking at the Gfs 12z operational...summer won't be rolling on beyond next midweek, it looks pretty autumnal beyond that, especially further north..so unless the gfs is very wrong, it will soon be time for a new thread!!

Yes, ok, but GEM looks the opposite, obviously a lot of uncertainty up front with the ex-tropical storms, but GEM has a nice anticyclone over the UK at T240, with a system out west that might push it on East! Six of one, half a dozen of the other at the moment!

[Mike Poole]

Track of ex-Helene being firmed up now, key time looks early Tuesday morning.  Wind gusts from GFS and FV3 at T60:

Looks like the really strong winds are confined to a relatively small region, a sting jet responsible  maybe? But it does look like it is going up the Irish Sea.

 

Edited September 15, 2018 by Mike Poole

[Frosty.]

The GEFS 12z mean in the mid / longer term indicates strong support for high pressure building in bringing predominantly pleasant days with sunny spells but probably some cold nights with mist / fog patches and a risk of slight frosts in prone spots..the finest weather lasting longest further south.☺

[NorthYorksWeather]

Some lovely charts later in the 12z run for those ready for some cold Autumnal weather, quite a cold pool for September incoming from the east.

-4c upper 850s not far off the east coast

[Mike Poole]

4 minutes ago, vizzy2004 said:

Some lovely charts later in the 12z run for those ready for some cold Autumnal weather, quite a cold pool for September incoming from the east.

-4c upper 850s not far off the east coast

Why on earth would you want this now?

Yes in two months time for sure.

 Meanwhile, ECM 12z, has this at T192:

 

[Scorcher]

23 minutes ago, vizzy2004 said:

Some lovely charts later in the 12z run for those ready for some cold Autumnal weather, quite a cold pool for September incoming from the east.

-4c upper 850s not far off the east coast

I take it you've ignored the ECM then? It shows basically the opposite to the charts you've posted. 

Lovely charts for those ready for some warm weather. 15C uppers in some parts of the south!

Also much closer to the reliable than the cool charts the GFS is showing.

Edited September 15, 2018 by Scorcher

[Frosty.]

The Ecm 12z is a really mixed bag of summery alternating with autumnal, the warmest days further south and coldest further north with a risk of slight frosts at times..certainly not boring output with an ex hurricane to come early next week introducing very warm / humid tropical air and for the n / w  very wet and windy for a time!

[mb018538]

Still looks a bit up in the air - perhaps moving back a tad from the high pressure domination it looked like we may get as low pressure and the jet remain active to the north.

The ensembles are starting to trend a bit cooler, with a noticeable dip away in temperatures compared to 24/36 hours ago. Caution should be exercised though as there is a lot of scatter at day 4, with one member going for 850s of 0c, and another going for 15c at the same time! With that much uncertainty, it’s hard to really know what will happen into next weekend and beyond.

[feb1991blizzard]

Hurricane force winds anyone?  Bye N.Ireland.

[ICE COLD]

4 hours ago, Scorcher said:

I take it you've ignored the ECM then? It shows basically the opposite to the charts you've posted. 

Lovely charts for those ready for some warm weather. 15C uppers in some parts of the south!

Also much closer to the reliable than the cool charts the GFS is showing.

Why are people not aloud to post charts that show cold/wet/windy weather ?? We all don't have to love scorching hot weather . You mention some lovely weather with 850s touching 15 in the south but its only a one day wonder at T192 . Back down to where they should be for the time of year towards the end . Lovely Jubbly 

Edited September 15, 2018 by ICE COLD

[ICE COLD]

1 hour ago, feb1991blizzard said:

Hurricane force winds anyone?  Bye N.Ireland.

Careful Feb you can't post charts like that in here , the summer gang will be on ya . That quite a big storm 70 to 80 mph winds up north . Even down south it's pretty windy around 50 mph . 

[Mokidugway]

Boo looks like a northern  England  event

[Seasonal Trim]

Can we please stop this coldy/mildy nonsense. This is the model thread. And if it's shown in the models, it's valid for discussion. 

Edited September 16, 2018 by Nizzer

[Iceaxecrampon]

6 hours ago, Mokidugway said:

Boo looks like a northern  England  event

As per usual never a dull moment and all that.....

But then again it’s not a snow event. 

[Mike Poole]

Just to give an idea of the uncertainty in he reasonably short term, it's interesting how different the UKMO is compared to GFS and GEM at just T96:

The UKMO just doesn't have the low affecting the UK, it's  a mere kink.  Interesting to see what ECM take is later.

[Mike Poole]

Moving on with the 12s, here's the GFS at T228, the anticyclone sets up just to the west to give settled weather but no real warmth:

On the other hand, the GEM positions the high in pretty much the perfect place to give a late blast of summer:

And of course, a shift west from these two examples of the current uncertainty would bring in the northerly flow suggested by some models yesterday.  I think we probably need to get Helene out of the way before this is all resolved.

[Singularity]

The situation this coming weekend strikes me as being one of high potential development but in a direction that's unclear and susceptible to the slightest of variations in the balance of play; signs are some amplification to the flow may kick in while there's a strong ridge trying to build from the south, and this can result in anything from a major plume to a chilly northerly-type flow... as GEM and GFS handily illustrate this evening. I really hope GFS is just going feedback-crazy with those Thursday and weekend storms; they look potentially very damaging to the still leafy deciduous trees of our lands.

That being said, recent over-enthusiasm for sending the atmosphere on a high-amplitude GWO orbit leads me to be sceptical of so much amplification taking place. The flatter ECM 00z may be a better guide in light of this. Less exciting for sure, but that's just how it goes sometimes.

[Frosty.]

There's some snow on the Gfs 12z operational next weekend with arctic air digging south into the far north...hopefully we will see much more of that as we go deeper into autumn..and then winter!❄❄❄

Edited September 16, 2018 by Frosty.

[Had Worse]

….. and winter Frosty

[Allseasons-Si]

There is some topsy-turvy weather in the ens and i do hope that the daughter low modelled in some of the ens at 156>> doesn't come off because that would pose a threat for some distruction in parts of the country but there is equally some nice ens members in there too post 156

after this clears through there looks to be some chilly nights with the wind swinging round to a northwesterly as can be clearly seen on the gefs ens chart with the 0c isotherm clearing the south and the 850's diagram below

the gfs op and control have the system but the gfs/p and the latest ecm doesn't,so it will be interesting what outcome becomes correct

i don't have the latest from the cpc anomly's yet but last night's matches the ecm/gfs/p scenario.

 

 

 

 

 

Edited September 16, 2018 by Allseasons-si

[Snowyowl9]

20 minutes ago, Frosty. said:

There's some snow on the Gfs 12z operational next weekend with arctic air digging south into the far north...hopefully we will see much more of that as we go deeper into autumn..and then winter!❄❄❄

 

1952 when Scotland had snow in September a very rare event in any situation.

[Allseasons-Si]

Scotland ens diagram and there is some snow rows in there

[Glaswegianblizzard]

4 minutes ago, Snowyowl9 said:

1952 when Scotland had snow in September a very rare event in any situation.

Highest tops in Scotland can have snow at any time of the year. I think the image above is likely suggesting snow in the Cairngorms, which would be in keeping with that.