Model output discussion - hot spell beckons but then what?

[Catacol]

Hot few days coming - plus most certainly some instability due to lower pressure sat just off to the west. Exciting spell probably - hot for those that like it, and some spectacular storms for those of a more thundery persuasion. What more could you wish for in summer?

It's a single snapshot of a single driver....but the current GFS assessment of the pacific over the next week is also interesting. Nino footprint fading quite fast from this image, with anomalous easterlies taking over at the dateline. This would suggest on its own a weakening of support for a strong Euro high and instead a changing of the wavelength to see the trough gaining influence as we approach August.

EC probability charts at the further end of decent resolution also show a similar trend

 

So - the clash in airmasses looks set to continue with perhaps the trough beginning to win out over time. Cue more potential for instability perhaps because even as the block is nudged east it will continue to feed hot and dry air into the mix periodically, running into cooler and more moist air to the west.... could get quite interesting.

[MATTWOLVES 3]

Looking at the extended ecm ensembles I would say it still looks like no definite sign of any weather pattern dominating. The mean is around 8c with a fair few members above this... Probably 60/70%...the pressure remains around 1015mb..with say a 50/50 split of either above or below!! Based on this evidence I would say a good shout would be for relatively unsettled at times conditions, to the NW, a bit like what the EC46 is flagging up, and for much better prospects the further SE one travels... August could well turn out decent for these areas.. 

Edited July 21, 2019 by Mattwolves

[Ben Sainsbury]

Wow, the Netwx model showing three 38'c icons for Thursday at 3pm over London/Thames Estuary! All time temperature record likely to be broken with this chart.

Edited July 22, 2019 by Ben Sainsbury

[shaky]

Arpege 18z much further west at just 60 hours!!!

[Porto]

GFS 00z more or less similar to the last run, perhaps fractionally cooler (raw temps suggest 36c instead of the 37c in the 18z run) but really its practically identical up until Thursday.

[knocker]

The North Atlantic 500mb and surface analysis for midnight and the 0300 UK chart

A cloudy start to the day, particularly in western regions with rain around as can be seen with a glance at the above chart. Which also indicates how warm and muggy it is in some areas. The cloud will tend to clear south east and eastern regions resulting in a very warm day whilst the it will linger in the west with some bits an bobs of drizzle/rain early on. .But the  warm front will continue to bring more persistent rain to western Scotland through the day

Th rain over western Scotland will persist as the warm front, associated with the low west of Ireland, moves slowly north before clearing by dawn. Some drizzle also down western coasts and becoming cloudy in central and southern England and thus another muggy night.

Any cloud will clear Tuesday morning and warm/hot day beckons much of the UK with just some cloud still in the north west of Scotland. But there is movement in the Atlantic as another upper trough moves east.aiding the amplification and WAA close to the UK

Overnight Tuesday and through weds the two upper troughs have merged and the new trough is just about neutrally aligned west of Ireland. On the surface this has pushed the old low further north and developed a more intense feature to the south west. Another hot day, particularly in the south east,but all of this maneuvering has pushed a couple of troughs and a weakening cold front across the UK and the cooler air mixing with the very warm/moist in situ air is a recipe for thunderstorms and cloud , the detail to be sorted later.

By Thursday the analysis has become somewhat complicated with the upper trough now slightly negatively tilted over Ireland with the cold front from the old low starting to be joined by an occlusion associated with the new low which is now just west of southern Ireland. So another warm/hot day but with the ongoing possibility of more storms and possibly increasing cloud temps may vary regionally although still likely to be hot in the south east.

By Friday the upper trough has moved east and the surface cold front is over the North Sea so although there are a couple of fronts/troughs in the circulation of the low which is now south of Iceland it should be a sunny day with the odd shower in the now cooler airmass

 

 

[knocker]

Looking briefly at the weekend with the gfs

Another upper trough enters the Atlantic arena so low pressure dominates the eastern atlantic whilst the subtropical high is now ridging NW towards the high cell over the Arctic with the trough, mentioned in previous posts, aligned down eastern Europe Portending a showery weekend with perhaps some longer periods of rain

[knocker]

A quick update with this mooring's fax charts for tomorrow. They have an upper frontal system with a surface trough tracking north from a shallow unstable low over France. This wil have implications for our weather, the details of which I'll gladly leave to the professionals

 

Edited July 22, 2019 by knocker

[mb018538]

Not much change this morning - still on course for a direct hit on Thursday, arpege etc showing 36c in the afternoon. Until then the heat proper arrives today with 30c possible in eastern areas with a sw flow

[Guest]

So it seems like there are there are 3 main questions between now and Friday. 

1. What will be the extent of thundery activity? Tomorrow’s fax chart looks to end the thundery drought here in spectacular style. Also how will debris from overnight storms affect insolation through wed/thurs

2. How widespread will the heat be Thursday? GFS showing just 24/25c across inland Dorset as the Atlantic flow takes hold, Arpege shows 31-33c

3. What will be the max in the SE on Thursday? I’m thinking currently something like this.

34C 100%

35C 90%

36C 80%

37C 65% 

38C 50%

39C 40%

40C 20%

[mb018538]

6 minutes ago, Alderc said:

So it seems like there are there are 3 main questions between now and Friday. 

1. What will be the extent of thundery activity? Tomorrow’s fax chart looks to end the thundery drought here in spectacular style. Also how will debris from overnight storms affect insolation through wed/thurs

2. How widespread will the heat be Thursday? GFS showing just 24/25c across inland Dorset as the Atlantic flow takes hold, Arpege shows 31-33c

3. What will be the max in the SE on Thursday? I’m thinking currently something like this.

34C 100%

35C 90%

36C 80%

37C 65% 

38C 50%

39C 40%

40C 20%

I think my percentages would be:

34c 100%
35c 100%
36c 70%
37c 40%
38c 20%
39c+ 5%

[mb018538]

Steady as she goes on the ecm 00z run:




850s up at 22-23c through Thursday. Mid to upper thirties incoming.

[MattStoke]

1 minute ago, mb018538 said:

Steady as she goes on the ecm 00z run:




850s up at 22-23c through Thursday. Mid to upper thirties incoming.

Difficult to tell how far west the highest uppers get due to the large time jump between each frame.

[mb018538]

Just now, MattStoke said:

Difficult to tell how far west the highest uppers get due to the large time jump between each frame.

I'm fairly sure they wouldn't go from the Thursday to Friday frames without going through the UK first....just check the GFS run which is similar.
Building up through Thursday, the edging out east on Friday.

[Man With Beard]

No obvious changes on the main models this morning wrt Wednesday/Thursday. UKMO looks slightly west of yesterday, GFS fractionally east, ECM pretty much where it was. I would expect the temperatures forecast yesterday to be repeated today, so mid to high 30s possible with the outside chance of 40 being reached for the very first time in the UK? 

Later in the week, the Atlantic really struggling to breakthrough, still probably just enough to make the weekend more on the changeable side, but it's notable in each run how the block to the east is getting stronger for Friday / Saturday. 

 

[MattStoke]

Surface temperatures for Kent on Thursday from the latest ECM. 37’C the highest on this run.

[Man With Beard]

ECM raw max temperatures this morning are Mon 28, Tues 30, Wed 32 and Thurs 37. If what usually happens happens, add between 2 and 4 to get the actual maximum. 

Areas that could reach 35 or more on Thursday possibly from a line south and east of Sheffield, Birmingham, Oxford and Brighton. 

Edited July 22, 2019 by Man With Beard

[Summer Sun]

At the peak of the heat on Thursday afternoon ICON has temps of 30c or higher from Yorkshire right down to the south

Some parts could see a drop of 10c or maybe even a bit more by Friday 

 

[knocker]

Thick fog just cleared here now just Stratus and as expected it's cloudy just about everywhere at the moment

 

[Methuselah]

GFS 00Z for Thursday clearly has the potential for being an exceptional, if not record-breaking, event:

   

...The GEFS ensembles are as follows:

   

   

So, post-apocalypse, daily maxes look set to be mostly within the 22-26C range? Nae bad!

The man from Del-Monte he say YES!

Edited July 22, 2019 by Ed Stone

[Guest]

Arpege doing a job job this morning with precip forecast picking up the heavy drizzle Bournemouth currently being subjected too, not a great start to the heatwave......

seriously though it could be quite a poor morning and early afternoon in the South west hence the much lower modelled temps.

Edited July 22, 2019 by Guest

[Paul]

UKV going for a scary 39c or so on Thursday on the 3z run this morning...

 

[mb018538]

Just now, Paul said:

UKV going for a scary 39c or so on Thursday on the 3z run this morning...

 

How accurate does the ukv tend to be?? Can’t say I’ve got tons of experience in using it for predicted temps!

[Summer Sun]

00Z ECM peaking at 38c on Thursday afternoon

[mb018538]

Even if the UK record doesn’t go, I’d say there is a very strong possibility of the July record being broken - (36.7c, 1/7/15, Heathrow). Simon King has put one foot aboard the hype train this morning and mentioned that 36/37c is possible Thursday....