I've never, ever understood why people fail to look at the ensemble guidance, be it winter or summer.

As I've posted a bit recently, down here at least the ECM ensembles have been rock-solid in supporting a warm spell, with a low chance of it turning hot (i.e. 28C for London) - 10% to 20% chance of that, as has been the case for days.

The 850 ensembles similarly show a very low chance of 20C 850s affecting us, regardless of what op runs are showing.

Here, again, is the link to the ECM ensembles. I know I posted this link endlessly during the winter, but it bears repeating. Hell, we waited well over a decade to get this data, make the most of it while it's still free!

https://weather.us/forecast/2643743-london/ensemble/euro/temperature

(EDIT: Not to say we won't see 28C or above, of course, just that it's not the favoured option in the ensembles. It's similar to rolling a die and hoping for a 6.)

I think people do look at the ensemble output. It needs to be used with care though, and with multiple models.

Take today’s ECM ensemble. Even the top of the range only gets us to 24C yet it will almost certainly have hit 28C in London this afternoon. 

The pattern across all models says warm uppers will visit the U.K. next week. The uncertainty is the intensity, duration and how settled or otherwise it’ll be. 

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Op was one of the less hot runs . Control has some prolonged warmth.  Looks fairly dry aswell some thunderstorms about though probably. 

 

 

 

 

 

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I think people do look at the ensemble output. It needs to be used with care though, and with multiple models.

Take today’s ECM ensemble. Even the top of the range only gets us to 24C yet it will almost certainly have hit 28C in London this afternoon.

GEFS had 23C as the median max, FWIW.

http://www.meteociel.fr/cartes_obs/gens_display.php?x=306&y=141&run=12&ville=Londres&runpara=0&type=3&ext=1

I blame the models' handling of sunny days, they do indeed undercook things for whatever reason.

If it's cloudy, though, or there's a bit of a breeze (not the light wind of today) then they tend to be more accurate in my experience.

As I said, a warm spell looks likely. A hot one - less so, at the moment.

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GEFS had 23C as the median max, FWIW.

http://www.meteociel.fr/cartes_obs/gens_display.php?x=306&y=141&run=12&ville=Londres&runpara=0&type=3&ext=1

I blame the models' handling of sunny days, they do indeed undercook things for whatever reason.

If it's cloudy, though, or there's a bit of a breeze (not the light wind of today) then they tend to be more accurate in my experience.

As I said, a warm spell looks likely. A hot one - less so, at the moment.

 

It's strange isn't it 27c in quite a few places today not just London.  Add 3 or 4 degrees to a warm spell and it becomes a hot one. Time will tell but decent output tonight though if you like heat.

 

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We need to define hot. I would stay it starts at 30C. Very hot is 34 or 35+. Warm 25C, perhaps “very warm” 27-30?

Odds on for a day or two of very warm next week. I’d give us evens to hit 30C, and maybe 10% chance of 34+

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Well the ECM is hot 850s wise any way. 16c at 144h, 19c at 168h and 192h. France central Europe boils. 

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Often wet for many and often warm for most sums that ECM run up, with a very disturbed pattern evolving toward the end.

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The rolling boil continues on ECM into 216hrs. And with a build of pressure. France has a go at beating its one month old all time record.

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Full scorchio by 216h 23c 850s in the SE. 

 

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Full scorchio by 216h 23c 850s in the SE. 

 

Indeed, this op run would produce ~35C in the SE on Thu, but then the North Sea A/C would switch on Fri with mid/high-20s.

40s for Tim of course.

 

Indeed, this op run would produce ~35C in the SE on Thu, but then the North Sea A/C would switch on Fri with mid/high-20s.

40s for Tim of course.

 

not far from perfect really 

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Indeed, this op run would produce ~35C in the SE on Thu, but then the North Sea A/C would switch on Fri with mid/high-20s.

40s for Tim of course.

And 30s for Bournemouth and Chivenor on Friday I reckon.

Perfect evolution because the longer term looks settled in this scenario.

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We need to define hot. I would stay it starts at 30C. Very hot is 34 or 35+. Warm 25C, perhaps “very warm” 27-30?

Odds on for a day or two of very warm next week. I’d give us evens to hit 30C, and maybe 10% chance of 34+

I agree, but best to remember some folk are from colder parts of the country where it seldom hits the the upper 20's let alone hit 30.

 

I agree, but best to remember some folk are from colder parts of the country where it seldom hits the the upper 20's let alone hit 30.

Indeed. To me 'hot' starts at 25C. My July/August average max is around 19C so at 6C above avearge that's about right. In London the July average is I believe around 23C so their 'hot' starts at 29C, which again is reasonable. I accept that this is drifting off topic now for the MOD thread so I won't comment further although the consideration of what constitutes warm/hot/very hot etc by people in various parts of the country would most certainly be an interesting discussion in a more appropriate thread )

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Indeed. To me 'hot' starts at 25C. My July/August average max is around 19C so at 6C above avearge that's about right. In London the July average is I believe around 23C so their 'hot' starts at 29C, which again is reasonable. I accept that this is drifting off topic now for the MOD thread so I won't comment further although the consideration of what constitutes warm/hot/very hot etc by people in various parts of the country would most certainly be an interesting discussion in a more appropriate thread )

Best way is to use metoffice heatwave threshold i find.. 32C for London 31C for rest of southeast... Coolest is northeast England at 28 😂

https://www.metoffice.gov.uk/public/weather/heat-health/#?tab=heatHealth

 

Anyway looking good for heat potential here.

 

http://old.wetterzentrale.de/pics/MT8_London_ens.png

 

Raw ECM output has 37C in London next Thursday

https://weather.us/images/scale/model/us/modez.png

And in North Kent too (Brogdale maybe)

 

 

 

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MO looking increasingly toasty next week in the south.

Let us hope the rain forecast over the weekend is delivered else gardens and crops will get some serious stress by the end of next week.

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MO looking increasingly toasty next week in the south.

Let us hope the rain forecast over the weekend is delivered else gardens and crops will get some serious stress by the end of next week.

The set-up is dependent on the lower pressure anomaly West of Iberia, far from certain to happen and the Atlantic low being further East and South is the likelier scenario.

 

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We need to define hot. I would stay it starts at 30C. Very hot is 34 or 35+. Warm 25C, perhaps “very warm” 27-30?

Odds on for a day or two of very warm next week. I’d give us evens to hit 30C, and maybe 10% chance of 34+

Those values are pretty much inline with my thinking. 

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ECM 12z was off the scale tonight. 

https://www.theweatheroutlook.com/twodata/ecmwfens.aspx?run=12&lg=850&lglocation=london

 

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