Model output discussion - hot spell beckons but then what?

[Polar Maritime]

The cool Northerly as touched on by Cap't above from the GFS into Wk2, Possible first frosts in the Glens..

[Methuselah]

So, the GEFS 00Z ensembles strongly suggest a week-long 'cooler' period, as the -AO does what it does; though, as it's been mostly -ive since May, one could argue that, we've been rather lucky regarding July's heat and sunshine?

   

   

But, there's nothing in there that would point toward writing-off the rest of August.

 

[I remember Atlantic 252]

3 minutes ago, Polar Maritime said:

The cool Northerly as touched on by Cap't above from the GFS into Wk2, Possible first frosts in the Glens..

Aye but looking at it positively, not negitavely, still reasonable temps for most of the UK for 7th Aug!

[Polar Maritime]

1 minute ago, I remember Atlantic 252 said:

Aye but looking at it positively, not negitavely, still reasonable temps for most of the UK for 7th Aug!

I was looking at it extremely positively I can assure you 

[Frosty.]

Although the GEFS 0z mean shows a cooler trend longer term this doesn't preclude the chance of a plume popping up or a generally much warmer spell, the continent shows more scorching potential and we have already had 2 plumes this summer...so far!!!!!!!!

Edited July 29, 2019 by Jon Snow

[Methuselah]

And, at T+177, and not for the first time this summer, the 06Z has us in a no-man's land:

   

[knocker]

The EPS medium term anomaly this morning is showing a pattern that has been indicated for two or three days now. Low pressure over Europe with associated trough running south over the UK whilst high pressure ridges unto Greenland in conjunction with the vortex lobe/trough northern Canada Thus a westerly 200mb wind field running south of these features across the UK (just) so it is axiomatic that the precise orientation of the east Atlantic trough is important when it comes to the detail which generally is likely to be changeable with temps around average

[Methuselah]

Well, this pattern looks strikingly familiar (both resistant to change and very keen to recur?) IMO: a weakish Greenland block, plenty of heat over the nearby Continent, and LP systems kinda stuck somewhere in between? The HLB threatens but more than likely fails to deliver...Again!

   

[Man With Beard]

The faint hopes of the clusters yesterday morning seem to have drowned with the floods upcountry. 

No proper clusters given this morning, but last night's were fairly representative of this T300 mean:

Quite a significant mean low at this range over northern areas, potentially affecting all. Not pretty except for ducks!!

By mid-month ... it would be wrong to say if the tendency is for more of the same or an improvement, too far out and lacking in strong anomalies, but at least the T360 chart is lifting the trough slightly.

[Methuselah]

Nowt new in the 06Z ensembles:

   

   

As 'others' have suggested, we may be going to exchange warmish convection (LP to our NW) for instability of a rather cooler (LP to our NE) variety, around or soon after, mid-month...?

[MATTWOLVES 3]

42 minutes ago, Ed Stone said:

Nowt new in the 06Z ensembles:

   

   

As 'others' have suggested, we may be going to exchange warmish convection (LP to our NW) for instability of a rather cooler (LP to our NE) variety, around or soon after, mid-month...?

Interesting point made by you there Pete! Low pressure to the NE towards mid month bringing a cooler W/NW feed and unsettled. A signal that Exeter are saying is growing in confidence!! I'm not so sure how you can have increasing confidence in 2 weeks out though tbh. Just looking at the extended ECM mean out to mid August, we have a mean around 8c...the pressure remains steady during the 1st week,around 1010mb. During the 2nd week we see a slight upturn, with the pressure rising to around 1014mb. All academic, has its a long way off.... Much to far off to say with any certainty that signals would be strong. So perhaps we should just see how this upcoming week pans out before we make to much judgement on the beginning of August. 

[Frosty.]

The Gfs 12z operational brings a window of drier and sunnier weather later this week as trough influence decreases and ridge influence increases...and it's official, the recent heatwave brought the highest temperature record of 38.7c!!!!!

Edited July 29, 2019 by Jon Snow

[Methuselah]

At least -- from the GEFS 12Z -- things look like staying just on the warmer side of average, for the first half of August?

   

   

Though, by the same token (it's only one run from one model!) desertification of the UK still seems some way off!

[knocker]

The development of this quite intense low, near the left exit of the jet, to the south west of Cornwall is a tad unusual at this time of year and not without interest.

Over tonight and through tomorrow it will track north east to be centred near Hull by midnight tomorrow

The occlusion associated with the low went through here about 1300  and it's now continuing to track north east along with the quite narrow rain band. But the main interest now is the convective activity with the low itself which is already effecting the south west, This activity will move north east overnight and through tomorrow before subsiding by late evening and will effect most western and central regions and involve frequent heavy showers with thunderstorms and intense localized intense downpours in the mix And for a time quite strong winds along the south coast

Cloud top temps also give an idea of the scale of the convection as some these will around the 30, 000ft mark

Edited July 29, 2019 by knocker

[Man With Beard]

A very autumnal day tomorrow in the south, and then further north on Wednesday - but after that, the ECM tonight suggests not too bad up to and including the weekend (esp. further south and east). The Atlantic low runs out of gas, nearly stalling - however, with the lack of a plume event, temperatures warm rather than hot - low 20s over most of England, possibly up to 27/28C in the SE corner at times. 

[northwestsnow]

23 minutes ago, Man With Beard said:

A very autumnal day tomorrow in the south, and then further north on Wednesday - but after that, the ECM tonight suggests not too bad up to and including the weekend (esp. further south and east). The Atlantic low runs out of gas, nearly stalling - however, with the lack of a plume event, temperatures warm rather than hot - low 20s over most of England, possibly up to 27/28C in the SE corner at times. 

Yes, my concern at the moment is not so much the potentially thundery spell this week, its more the signal for the Atlantic trough(s) to get trapped near or over the UK day 8 onwards..

 

GFS going the same way, hopefully this trend can be reversed a little over the coming days as i'm beginning to fear a poor start to August.

Edited July 29, 2019 by northwestsnow

[MATTWOLVES 3]

Lord have mercy.... I was wandering why the posts have been thin on the ground today!!! Just one look at the precipitation charts tomorrow.... And now I no why!! It's going to be great for ducks or for folks dancing in the rain... Rest assured guys... Don't worry about watering your plants this evening, not unless you want to drown them. Some large rainfall totals on Tuesday... Lots of showers on Wednesday and these more focused to the NE at this point.... Beyond that shower risk becoming less to the South with more in the way of warm sunny spells... This leading to a decent start to the weekend... Temps perhaps ranging from... 20-27c North to South... Whatever your weather brings... Try to enjoy it, and stay safe... A very good evening to you all.

Edited July 29, 2019 by Mattwolves

[danm]

41 minutes ago, Man With Beard said:

A very autumnal day tomorrow in the south, and then further north on Wednesday - but after that, the ECM tonight suggests not too bad up to and including the weekend (esp. further south and east). The Atlantic low runs out of gas, nearly stalling - however, with the lack of a plume event, temperatures warm rather than hot - low 20s over most of England, possibly up to 27/28C in the SE corner at times. 

Yep, Thursday onwards looking much better on the ECM - especially further south and east. Some warm air getting into the SE during the weekend, high 20’s possible. 

The low mainly stays west of the UK on this run and only very slowly makes inroads, mainly affecting the W/NW.

[knocker]

This evening's EPS 9-14 mean anomaly pretty much as expected. Canadian vortex lobe/trough;Greenland ridge and Iceland trough complex overlying a strong westerly upper flow across the atlantic, portending changeable weather with temps around average.

[knocker]

Outlook - instability, thundery

The 500mb NH profile and the North Atlantic surface analysis for midnight and the 0300  sat image

The low is currently centred just south of Cornwall with the original occlusion draped across northern England where there is some showery activity associated with this. which will tend to move NW through the day. But the main convective activity, of frequent heavy showers with thunder and hail in the mix will be within the circulation of the low as it tracks NE. Much of Scotland and NE England will miss this and be quite sunny, as will elsewhere between the showers, It will be quite windy along Channel coasts as the low travels NE

The thundery showers will continue overnight but tend to be confined to northern and eastern regions of the England and perhaps northern Ireland as the low reaches the east coast.

By midday tomorrow the low is still just off the east coast but a trough embedded in the circulation will bring frequent thundery showers to the north and then later to western Scotland with the possibility of some intense downpours.By now the winds in the south will have abated.

Over Weds night and through Thursday the low slowly fills in the North Sea but the trough is still aligned across northern England so a continuation of thundery showers within the corridor of this. Elsewhere a few odd showers but generally sunny but cooler along North Sea coasts

Over Friday and Saturday the country is in a col as the low continues to drift east and a new upper low arrives to the west. But a convergence zone effects western Scotland and northern England so still heavy thunder showers here  Mainly sunny elsewhere, and warming a tad by Saturday, with the usual caveat vis eastern coastal regions.

Edited July 30, 2019 by knocker

[knocker]

According to the gfs during the latter half of the ten day period the high pressure continues to migrate NW and the trough conduit from the eastern seaboard to the European trough is established south of this across the Atlantic and the UK.

An over view of this would be changeable with sunny intervals/showers and the odd longer period of rain with temps around average.But any further amplification of the subtropical high in the vicinity of the UK would put a brake on easterly trough movement and thus portend a drier and warmer spell for some regions, particularly the south east.

[Methuselah]

Not an exactly 'pleasing' pattern suggested at T+195, by the GFS 00Z -- yet more rain?

   

And the GEFS ensembles don't paint a pretty picture, either, IMO:

   

 

   

Best not to 'gild the lily'?

[knocker]

The ecm pretty much o the same page as the gfs

[knocker]

The 0600 sat image sums it up. It's a foul day in these parts

[Djdazzle]

So glad that the record was broken so that July now holds it. August these days is a poor excuse for a summer month, and the models look like (although they could change) delivering our 17th consecutive poor / average one.