Model Output Discussions 12z 01/09/2016

[Frosty.]

The Gem 12z shows our weather markedly warming  / hotting up during the first half of next week, especially across the southern half of the uk with hot sunshine and increasing humidity from the continent with a growing chance of thunderstorms. Most of next week will feel like high summer across much of  England and wales.

[Man With Beard]

Well even though this situation looks marginal at face value, we may actually be on the brink on something quite exceptional here for September. The warmth for Tuesday is well documented, but the longevity of the heat has not been pinned down yet, and I'm now wondering if there's a sniff of it being hot on both Wednesday and Thursday, too. The ARGEPE shows nicely how this could happen. On the chart for Tuesday, note how far the heat stretches down through Germany and into Austria:

Now if the fronts on the developing low pressure stall anywhere to our south, we will suck up all of that heat. Which is precisely what the ARGEPE thinks will happen - here's the chart for Thursday morning:

in other words, most of the UK (south and north) sits in 16C/17C/18C uppers for 48 hours. That's unusual even at the height of summer. But where's the rain?

Largely to our south too. So with sunny spells, the idea of 30C on three successive days is not an impossibility here. Of course it's all on a knife-edge and southern/western areas may encounter more cloud and some rain if the set-up changes slightly (perhaps more akin to GFS).

How's the ECM seeing this tonight? Not that dissmiliar (just very slightly lower uppers)

    

Bearing in mind these are T72 / T96 / T120 charts, there has to be a good chance of verification. 

Edited September 10, 2016 by Man With Beard

[Frosty.]

The GEFS 12z mean shows the hot plume at its height next tues / wed when temps across southern uk could be well into the 80s and possibly low 90s F..this will be truly exceptional for mid September..hot sunshine, a risk of thunderstorms..it will feel like summer next week, it's still warm / very warm by Thursday too.

[Summer Sun]

ECM shows some very warm to hot weather most of next week seems like the closer we're getting to the event it's getting extended

[Frosty.]

The Ecm 12z is an upgrade on the 00z with the very warm / hot weather lasting almost to next weekend. The charts just look so summery its unbelievable..time left for another BBQ or 3

Somewhere in the south will get above 90F next week if anything like this verifies!

[Waterspout]

1 hour ago, Frosty. said:

this will be truly exceptional for mid September..

I really enjoy reading your posts Frosty, and rarely post in here, but let's not get too carried away with hyperbole regarding Autumn Hot spells. A brilliant article by Mr Eden Sums it up, and we are not even Late September yet......

http://www.bbc.co.uk/news/magazine-15127159

[Frosty.]

Thanks Waterspout and that was a very interesting article too

The Ecm 12z ensemble mean shows a hot plume developing through the first half of next week just as the operational with increasing heat and humidity from the south, at least to England and Wales with max temps well into the 80's F further south and possibly into the low 90's F across parts of south / southeast England and plenty of scorching mid september sunshine but with a growing chance of heavy showers and thunderstorms...so, no change to proper autumn in the week ahead, very summery until later next week.

[summer blizzard]

Although there's nothing intensely cool in the model output it is at least a comfort for some that models show a much more normal picture afterward in terms of heat..

[Scorcher]

1 hour ago, Waterspout said:

I really enjoy reading your posts Frosty, and rarely post in here, but let's not get too carried away with hyperbole regarding Autumn Hot spells. A brilliant article by Mr Eden Sums it up, and we are not even Late September yet......

http://www.bbc.co.uk/news/magazine-15127159

Of course very warm spells do happen i  September, but if the ECM is to be believed it would be an exceptional week.

We very rarely get uppers above 15C in NW England in July or August, let alone September. If that's not exceptional I don't know what is. Apart from 2011 I can't remember too many temperatures of 26C or higher in Manchester in September at all.

[Summer Sun]

Tuesday and Wednesday both very warm to hot for large parts of England and Wales 

[blizzard81]

17 minutes ago, Summer Sun said:

Tuesday and Wednesday both very warm to hot for large parts of England and Wales 

I don't care what anyone says - this is truly exceptional for September.

[4wd]

September often has a very warm spell and can sometimes have the hottest day of the year.

You only need go back to 2011 and some places were close to 30C in the closing days.
It was 25C here on the 30th.
Also I recall an exceptional hot spell in September 1982

[Man With Beard]

Small differences again this morning at T72/T96 - again it's the GFS which is slightly more progressive in pushing the heat away - I'd back the ECM every day of the week in the situation/timeframe though, and it's unchanged from last night - hot Tuesday until Thursday for a large number.

[northwestsnow]

ECM again better for duration this morning with the very warm/hot weather hanging on until Thursday night

GFS more progressive in ushering the heat away but a change looks likely by the weekend on all the NWP this morning as the high gives way.

Either way a very spicey end to a pretty average summer round these parts although i appreciate it will probably go down as a warm summer for the South East in particular..:)

Edited September 11, 2016 by northwestsnow

[MR EXTREMES]

well the gem would be great if we were in the depth of winter.

anyway the gfs certainly pushes the warmth away quicker than the rest.

but all the models do see autumn starting to show towards the end of there run and coming closer each day to autumn proper.

[Summer Sun]

Little change from ECM for the coming week overnight with the highest temps Monday to Thursday

By Friday the warmth will slowly be easing ahead of fresher air moving in

[Polar Maritime]

The NetWx-SR Model still showing a 'possible' 31/32c for Tuesday with very high Cape levels giving a good chance of convection. Certainly an interesting week coming up re detail, As records could very well be broken in some areas.

 

GFS certainly showing a cooling off from the West as we head into the weekend, And the PV starting to build momentum into the last few frames as we head into Autumn..

 

 

 

Edited September 11, 2016 by Polar Maritime

[Frosty.]

Almost time for another spell of sunny summery weather, the Ecm 00z is again glorious for the week ahead until and including next friday, glorious temperatures at 30c + across the south and locally somewhere in the south should reach the magic 90F between tues / thurs..a risk of T-storms too..enjoy it guys

Edited September 11, 2016 by Frosty.

[Nick L]

We've been lenient the past few days but despite repeated requests they are being ignored. This thread is for model discussion only. Don't copy and paste/screen shot BBC/Met Office forecasts in here please.

[Singularity]

This does now seem to be a classic disrupting trough scenario, with GFS struggling to break away the secondary low from the base of the parent trough.

If this was the heart of winter, GFS would likely be showing a lot of wintry weather while the other models would be threatening to leave us cold but dry.

Nice to root for the models keeping the low south on this occasion!

[Gordon Webb]

25 minutes ago, Singularity said:

This does now seem to be a classic disrupting trough scenario, with GFS struggling to break away the secondary low from the base of the parent trough.

If this was the heart of winter, GFS would likely be showing a lot of wintry weather while the other models would be threatening to leave us cold but dry.

Nice to root for the models keeping the low south on this occasion!

put simply what does this mean in terms of the weather

Edited September 11, 2016 by Gordon Webb

[Sky Full]

It looks good for the south and east of England next week but spare a thought for the west and south west where the weather could turn out to be very different.  It looks dire at times with persistent showers and longer periods of rain together with only average temperatures.  There might be some compensation in the form of storms but not by any means certain.  Anyway, it's nice to know that many will enjoy a return to warm and sunny conditions but probably for the last time this year as more Atlantic influence is indicated to follow.

[Matthew.]

8 minutes ago, Sky Full said:

It looks good for the south and east of England next week but spare a thought for the west and south west where the weather could turn out to be very different.  It looks dire at times with persistent showers and longer periods of rain together with only average temperatures.  There might be some compensation in the form of storms but not by any means certain.  Anyway, it's nice to know that many will enjoy a return to warm and sunny conditions but probably for the last time this year as more Atlantic influence is indicated to follow.

The GFS agrees

[phil nw.]

Some off topic posts again which have been removed-just chat no real model discussion.

One or two posters still not getting it.Please use the other threads for general weather chat -there are plenty to chose from-thanks all.

[Singularity]

29 minutes ago, Gordon Webb said:

put simply what does this mean in terms of the weather

Thanks for the question Gordon -

Essentially there is a low looking to develop south of the U.K., which most models then move east while keeping much of the U.K. clear of the associated cloud and rain - though a few showers could develop in the far south while the far southwest looks prone to a lot of cloud and perhaps a bit of rain. GFS differs in that the low drifts north and across the UK Tue night through Wed, allowing cooler, cloudier weather to move up from the southwest, though perhaps not without some storms firing off just ahead of that.

By Thu, GFS has it fresh and blustery with showers and some longer spells of rain, yet ECM and UKMO keep the very warm air in place and might be right for some homegrown thunderstorms.

I've conducted this whole analysis from my phone though, so it may not be as precise as usual.