Model output discussion - hot spell beckons but then what?

[I remember Atlantic 252]

slightly better EC, no filth, like has been shown, still FI though, yes not exactly great temps but dry

[I remember Atlantic 252]

11 hours ago, mb018538 said:

Growing possibility of a nasty trough/low affecting the UK as it slides from Iceland around the flank of the high pressure close by.



Still open to much speculation at this range - Dorian will undoubtedly be throwing a very large spanner into the works.

still hope not to see filth like this back

[knocker]

An option indicated by some clusters this morning

[Mike Poole]

Tonight's ECM in full:

Edging towards settled but not particularly warm, with the high tending to stay out west.  Would be fairly pleasant and benign for most, I should think.  

Polar vortex update:

The PV should form sometime between Sunday and Tuesday according to GEFS, which is very late.  How much that impacts on winter prospects from a cold persuasion, I wouldn't opine much on except to say it  probably isn't a bad thing.  Plenty of other things to watch as winter eventually approaches.

[Frosty.]

Just catching up, the Gfs 12z operational, for the most part was settled and feeling pleasantly warm in the sunshine but nights would be cool, especially where skies clear, there's plenty of high pressure / ridging. Moving on to the GEFS 12z mean, again, pretty decent, especially for the mid / longer term, at least across southern uk with plenty of azores ridging.. looking through the 12z perturbations there are some nice ones, if, like me you're hoping for further spells of summery weather in early autumn!

 

Edited August 30, 2019 by JON SNOW

[knocker]

The medium term NOAA and EPS mean anomalies are in pretty good agreement this evening with the TPV in the Franz Joseph area with associated troughs Greenland and east of the UK. The latter taking on a positive tilt south east of the UK as the subtropical high amplifies north east from a central position to the south west.Thus the strong westerly upper flow tends to abate and diversify close to the UK which would suggest nothing drastic lurking in the woodshed with the better and drier weather favoring the south west and temps still tad below average

In the ext period a tendency to lose any Atlantic amplification and thus a flatter westerly upper flow portending more changeable weather generally with temps still below average.

 

Edited August 30, 2019 by knocker

[knocker]

The North Atlantic 500mb and surface analysis for midnight and the latest sat image

The deepening wave on the cold front is currently bringing heavy rain to N. Ireland and western Scotland. This should quickly clear the former and then the latter by early afternoon as the wave tracks north east.Meanwhile the band of rain associated with the front will slowly traverse the country through today, becoming lighter on it's travels, clearing the east coast by 1800.Frequent showers will follow behind the front, particularly concentrated over N. Ireland and western Scotland. where it will be very windy and much cooler than the south east as the last vestiges of the hot weather disappear.

Once the rain has cleared mainly dry overnight in Wales and England but still breezy in the north with some heavy showers, courtesy of the odd front/trough in the circulation

On Sunday the country is in a cool north westerly as a transient ridge builds in the west and there will be frequent blustery showers in northern and western regions with hail and thunder in the mix

The transient ridge moves east across the country over Sunday night and through Monday but comes under pressure as another upper low tracks across the Atlantic and surface fronts track around it bringing wet and windy weather to the north

As the Atlantic trough continues to track east further fronts will bring frequent showers and longer periods of rain to the north on Tuesday and it will also be quite windy. The south again remains relatively dry

By Wednesday the subtropical high in the Atlantic is again amplifying resulting in a cold front tracking south east down the country in the north westerly flow, thus showers and sunny intervals

Edited August 31, 2019 by knocker

[knocker]

According to the gfs the country remains in a showery north westerly for the rest of the week but veering more northerly by Saturday as an upper low tracks east across Iceland around the amplifying ridge and then plunges south east into the North Sea down the western flank of the main trough

[knocker]

And better news vis Dorian

[knocker]

The ecm turning Dorian north east of Florida

[knocker]

The ecm drops  the rather weak trough south east into the eastern North Sea before consolidating over southern Sweden

[knocker]

The 0600 chart

[Methuselah]

A smidgen of hope of another warm-up, on this morning's GEFS 00Zs -- but only time will tell?

   

   

     

                                                          

[knocker]

I can see the clearance behind the front

[Iceaxecrampon]

3 hours ago, knocker said:

And better news vis Dorian

Yes - heading for good all Blighty!

[Frosty.]

The Gfs 6z operational is quite an autumnal run which is ok since autumn starts tomorrow, amazing how often a change in season brings a marked change in the weather but anyway, a mixed period ahead, best of any fine spells / ridging further south and at least the run ends with high pressure in charge but that's mid september.

Edited August 31, 2019 by JON SNOW

[Methuselah]

GEFS 06Z ensembles look more like a 1980s' computer-generated sci-fi 'landscape' than a weather prediction...Lots of uncertainty?

   

   

Engage thrusters!

[knocker]

1315 UTC

[chrisbell-nottheweatherman]

3 hours ago, Ed Stone said:

GEFS 06Z ensembles look more like a 1980s' computer-generated sci-fi 'landscape' than a weather prediction...Lots of uncertainty?

   

   

Engage thrusters!

How can such uncertainty WRT 850hPa temperatures and surface pressure lead to consistency of 2m temperatures and agreement on there being no usable rainfall?

[carinthian]

Just a bit of interest over here. Forecast team showing a developing low pressure storm over the southern North Sea towards the end of next week. One to watch. Portal forecasts of snow next weekend at 2000m level with lowering of freezing level to 2000m. Longer term , Scandi/ Russian block mid -September. An abrupt end to the Euro Summer season on the cards ? As always time will tell. Think the models may pick upon this soon.

C

[knocker]

As has been discussed in previous posts the detail for next weekend is a long way from being nailed down

Essentially at midnight on Friday we the TPV over the Pole with associated trough down through central Europe with an upper low tracking east from Greenland around the amplifying Atlantic sub tropical high.It's the direction of travel of this low from this point as the high continues to amplify which is of interest and this is the position 12 hours later

And by midday Saturday Obviously adjustments west are a no no

And the ext GEFS looking unsettled with temps below average

Edited August 31, 2019 by knocker

[knocker]

This evening's ecm has Dorian just brushing the Florida east coast before turning north

 

[knocker]

The ecm on the end of the week

[knocker]

The North Atlantic 850mb temp anomaly (Pm air now covering the eastern Atlantic) and the surface analysis

Apart from isolated showers in the west most of England and Wales are dry this morning with some high cloud around, but still a lot of showery rain over western and northern Scotland and to a lesser extent N. Ireland  This showery activity, with perhaps the odd clap of thunder, will spread east and as far south as Kent through the day Quite a stiff NW wind in the north

Sowers will linger a while in western regions this evening courtesy of an old occlusion, but generally a clear, albeit quite a chilly, night But the next frontal system is tracking around the ridge and more persistent rain will effect western Scotland and N. Ireland by dawn

Through Monday the system will bring heavy rain and strong winds to Scotland, particularly the west, and to a much lesser extent N. Ireland and NW England. Further south, apart from some showers in the west, it will be dry with sunny intervals

Over Monday night and through Tuesday the Atlantic trough continues to track east and merge with the one west of northern Norway and surface fronts associated with this will continue to bring rain and strong winds to northern and western regions with the south and east having the best of the sunshine

By Wednesday the trough has continued to track east but now has phased with the TPV over the Arctic establishing an elongated trough down through Europe 'trapped' between the east European ridge and the amplifying Atlantic subtropical high This results in much of the UK being in a north westerly wind with a lingering occlusion bringing rain to northern and western regions.

Over Thursday the pattern shifts a tad east and the eastbound energy keeps the Atlantic ridge subdued and thus a breezy showery westerly over the northern half of the country with the south getting the better of the sunshine.

Edited September 1, 2019 by knocker

[knocker]

According to the gfs the main features of the end of the week and over the weekend are the burgeoning of the subtropical high zones and then the strengthening of the jet across the Atlantic during the course of which the trough to the east is disrupted and a cut off upper low created over Europe