Model output discussion - hot spell beckons but then what?

[knocker]

High/res satellite at1200 UTC

[Frosty.]

Looking at the GEFS 6z I'm not seeing much sign of any sustained settled anticyclonic weather but I am seeing plenty of warm potential and probably quite humid at times with showery / thundery spells and sunny periods...some transient ridging too but this is only based on the above and doesn't preclude something better evolving during the coming weeks.

[Summer Sun]

Big changes ahead in the coming day's as we lose the heat and see thunderstorms initially then persistent heavy rain on Saturday for some the north of England and southern Scotland currently look to be the prime spot for the rain with up to 140mm possible over high ground by the end of the weekend according to UKMO and GFS

UKMO

GFS

ECM whilst wet doesn't have such extreme totals

[knocker]

The waving cold front will continue to cross the country though this evening and overnight thus a much cooler night for most but not the south east, The patchy rain associated with the front will tend to fizzle out but a more persistent  pulse associated with the occlusion will effect the south west and Wales by the morning. Further to the east the current convective activity will track north quite quickly but a more concentrated area with thunder in the mix will will track north this evening, mainly effecting East Anglia

[Frosty.]

According to ARPEGE 12z it could reach 38c!!!!!!..oops it already has..lol

Edited July 25, 2019 by Jon Snow

[Frosty.]

The Gfs 12z operational shows the first 38c I've seen on that model this week..and in real time now it looks rather accurate..until the official numbers are in!!!!!!!!.........really going to miss all this excitement once today is over!!!!!!!

[MATTWOLVES 3]

9 minutes ago, Jon Snow said:

The Gfs 12z operational shows the first 38c I've seen on that model this week..and in real time now it looks rather accurate..until the official numbers are in!!!!!!!!.........really going to miss all this excitement once today is over!!!!!!!

Maybe for not to long though mate, still talk of further hot plumes moving forward. Looking at the next few days it's cooler with some rain and showers around. The weekend not to bad in the West and SW. now moving forward next week perhaps more of a NW/SE split. There is talk of further heat from the continent, one thing for sure is we remain with a fairly warm air mass in place. Now after all the dramatics and hyperactivity of the last few days chasing that record, can we now all take a deep breath and calm down,and focus on the model output!!!! Plume 3 anyone.... Bring it on... Still buzzing

Edited July 25, 2019 by Mattwolves

[mb018538]

Ukmo and gfs poles apart at 144 this evening....weak ridge on gfs, trough over the UK on ukmo.

Still, with all the kerfuffle around the heat gone, we can get back to describing days of average temperatures, fronts and the like, which will go down a treat with some!

[Captain Shortwave]

The GFS seems to drag the -NAO far enough west to allow a downstream Euro ridge to build with low pressure trapped to our west. One thing to take note of is the pattern is so blocked we effectively lose any real source of colder air so even stuck under a low like the UKMO the 850s are still warm or indeed very warm. There could be a lot of rain but I suspect unless you get stuck under a front then temperatures could be pretty decent.

   

Really messy though

Edited July 25, 2019 by Captain Shortwave

[Frosty.]

It's been a great day, the GEFS 12z mean indicates 35c 95f, there is only 1 perturbation plus the operational that show 38c being reached, we reached just above 38c..I was hoping it would reach 39c because the media forecasters were saying 39c but reaching 100f in the uk is a great achievement, we may get a few more chances in the month ahead if we can tap into the continental flow again which is being hinted at!!!!!!

Edited July 25, 2019 by Jon Snow

[SnowBear]

It really just goes to show after watching the models over the last week and then following today just how difficult it is to get a 40°c in the UK.

[Kentspur]

Well that was a really testing day driving around Kent and all corners of London in a non air conditioned van as soon as 12 30pm there were already clouds gathering in the area of London I was in at the time and then there was full cloud cover at 2pm it was then I thought to myself were not breaking the all time record. But imagine if it had stayed sunny all day easily 40c I reckon a scary thought!

[Man With Beard]

On 20/07/2019 at 08:10, Man With Beard said:

On ECM raw temperatures charts, still record breaking potential, but a slight eastward shift means only very hot in the SE after Tuesday. Likely maximums would be Mon 31, Tues 34, Wed 35, Thurs 37-38

To round off this historic event, I like to look back and see how well the models were able to predict temperatures in advance. This was the situation on Saturday morning, when many other models were not even interested in extending the heat past Wednesday.

The actual official maximums were Monday 30.5C, Tuesday 33.7C, Wednesday 34.3C and Thursday 38.1C

The "science" of adding 3C to ECM raw temperatures has clearly worked again. Yes, it did have a spell on Sunday/Monday where it appeared today would be a bit hotter, but in general the ECM has been extremely consistent for many days with its temperatures. 

It was also spot on with temperatures as far out as D6 in the June event.

Obviously this is not "scientific", but all the same, it's built my confidence in using the ECM in this way when forecasting temperatures in a heatwave the future.

There was one error though - it did not initially see the heat building so far west and north. The dreaded easterly correction became a westerly correction!

[Mike Poole]

45 minutes ago, Man With Beard said:

To round off this historic event, I like to look back and see how well the models were able to predict temperatures in advance. This was the situation on Saturday morning, when many other models were not even interested in extending the heat past Wednesday.

The actual official maximums were Monday 30.5C, Tuesday 33.7C, Wednesday 34.3C and Thursday 38.1C

The "science" of adding 3C to ECM raw temperatures has clearly worked again. Yes, it did have a spell on Sunday/Monday where it appeared today would be a bit hotter, but in general the ECM has been extremely consistent for many days with its temperatures. 

It was also spot on with temperatures as far out as D6 in the June event.

Obviously this is not "scientific", but all the same, it's built my confidence in using the ECM in this way when forecasting temperatures in a heatwave the future.

There was one error though - it did not initially see the heat building so far west and north. The dreaded easterly correction became a westerly correction!

Yes, it is interesting to pick over how the models we've watched in the run up performed.   I've found the ARPEGE ensemble very good in terms of bounding possibilities, maybe he low end was too low, but converged towards the actual peak temperature. And it got the location of the hottest spots very well.  

AROME ensembles much further from the mark, particularly on the low side.  

ARPEGE operational run edged slightly too high before backtracking late in the day, but again got the location broadly right.  

Edited July 25, 2019 by Mike Poole

[MATTWOLVES 3]

I think the Ecm is looking much more positive than the ukmo... Low pressure looks less of a player, and quite a bit further West, allowing for some ridging to take place further south.... On the other hand I maybe suffering from heat exhaustion and seeing things all together wrong..

don't wanna get to excited but I feel another heating a coming on.... 

Edited July 25, 2019 by Mattwolves

[clark3r]

I think you maybe on to something maybe this one will hit 40

[knocker]

There is a reasonable agreement between the gfs and ecm NH 5-10 anomalies. The dominate features remain the strong TPV northern Russia and the high cell over Greenland  with a weak jet running east a fair way south the subtropical high can ridge weakly during the period isolating the Atlantic upper low which portends some fairly benign weather with some showers at the beginning of the period with temps a little above average

Edited July 25, 2019 by knocker

[cyclonic happiness]

Can anyone answer whether the +20'c 850s ,have ever got as far north as the Faeroe islands before??  that is truly astonishing to see?! :-0

[knocker]

Synops max temps

http://www.met.reading.ac.uk/~brugge/18.html

 

[MATTWOLVES 3]

EC46 looking positive tonight for August... Positive sea pressure anomalies, temps remain on the warm side where I feel continental influence may have some influence at times... Didn't see any dramatic pressure falls throughout the month ahead... Long way off and subject to change, but good signs all the same. 

[Paul_1978]

5 hours ago, SnowBear said:

It really just goes to show after watching the models over the last week and then following today just how difficult it is to get a 40°c in the UK.

Long may that record be unbroken. 

[MATTWOLVES 3]

8 minutes ago, Paul_1978 said:

Long may that record be unbroken

Makes no odds though to people who dislike heat. You won't feel a difference whether it's 36/37 or 40, getting regular occurrences of low to mid 30s is gonna be alot worse than a very rare 40c for people who suffer from these conditions. 

[matty007]

1 minute ago, Mattwolves said:

Makes no odds though to people who dislike heat. You won't feel a difference whether it's 36/37 or 40, getting regular occurrences of low to mid 30s is gonna be alot worse than a very rare 40c for people who suffer from these conditions. 

Correct.

[Big daddy 49]

1 hour ago, Mattwolves said:

EC46 looking positive tonight for August... Positive sea pressure anomalies, temps remain on the warm side where I feel continental influence may have some influence at times... Didn't see any dramatic pressure falls throughout the month ahead... Long way off and subject to change, but good signs all the same. 

If it's 23-25 and reasonable,in other words you can function,I'll be happy!.

[knocker]

The North Atlantic 500mb and surface analysis for midnight and the 0300 WV image

As can be seen the upper trough is now negatively tilted just the west and today the surface fronts will struggle north east against the blocking high pressure.Thus the band of rain, already effecting the south west, will do likewise and start to pep up on it's travels. Much cooler air will spread east during the day but it will stay warm in eastern regions, very much so in East Anglia and the south east.

Overnight the fronts will grind to a halt over the north east resulting in the moderate rain doing the same so a very wet night here whilst dry elsewhere,

The front starts edging back south west on Saturday as will the rain belt thus clearing the north east of Scotland Elsewhere a few showers and sunny intervals A much cooler day, particularly under the rain.

Over Saturday night and through Sunday the front moves a tad further south west otherwise little change

By Monday the pattern has developed as has been indicated previously with the high cell now north of Iceland and low pressure dominating the Atlantic and a new upper trough has arrived off the coast of Cornwall. The upshot of this is shallow surface low with associated fronts bringing rain to the south west whilst still some rain lingering over Scotland from the old front

The low fills and tracks south east on Tuesday but generally the UK is under low pressure so varied weather of showers in the west and drier in the east and now much cooler than of late

 

Edited July 26, 2019 by knocker