Model output discussion - hot spell beckons but then what?

[shaky]

8 minutes ago, matty007 said:

Well, GFS has been about 4c too low recently. So that would be 41c 

Which means the 32 and 33s you see around manchester and much of england could be 35 or 36 degrees instead lol!!

[Mapantz]

Please head over to the appropriate thread for general chat, please?!

 

[GeordieX9v]

Can 'only' see 38 on the latest ARPEGE. Unless it's just because I'm zoomed out.

[Cheshire Freeze]

Is the luck that we've been pushing all July about to run out with the turn of the month?

Some stunning N blocking once again shown there

[knocker]

The North Atlantic 500mb and surface analysis for midnight and the 250mb jet

Today sees the upper trough to the west become negatively tilted under pressure which initiates a surge of very warm air from the south whilst at the same time starting tracking the fronts to the west > east. All of this results in a hot day over much of the UK, exceptionally so in some central and eastern areas whilst there will be more cloud in western regions where it will be cooler. But the heat will trigger convective activity and storms will start to pop up over eastern, and then northern regions during the afternoon and as can be seen there are a couple of troughs appearing.

The cold front will continue to move east during this evening and overnight as the thunderstorms become more widespread over northern and eastern regions whist remaining  cloudy further west A fair bit of lightning around and perhaps some hail in the mix

By midday Friday the energy flows are 'squeezing the ridge north west as the pattern unfolds resulting in the cold front making slow progress so still very warm in far eastern regions.Cooler elsewhere but still storms likely in central and eastern areas

The pattern continues to evolve along the same lines on Saturday with thundery rain persisting along the now waving front

Little change with this scenario on Sunday

By Monday more upper troughs are arriving on the scene, tracking east under the high cell which is now north of Iceland and an intense little surface low could well bring rain to the south west during the afternoon

Edited July 25, 2019 by knocker

[knocker]

To continue briefly wth the gfs

Over the next couple of days an intense high cell is established over Greenland and TPV northern Russia with a westerly flow across the Atlantic portending changeable weather over the UK with temp around average

 

Edited July 25, 2019 by knocker

[Frosty.]

Well it looks like 38c 100f at least on ARPEGE 0z but could we see 39c 102f today?...please make it 40!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!..but it's affecting the train tracks today..wrong kind of heat of course!!!!!

Edited July 25, 2019 by Jon Snow

[knocker]

A couple of spot checks from the ecm for the weekend

[Man With Beard]

It's a really close call on the UK record on the 00Zs. The AROME is now largely looking at 36-37C with spots at 38C, while the ARPEGE has a larger area at 38C. I guess the issue is cloud, as some cloud and eventually rain will be moving in from the south and west this afternoon. When cloud becomes an issue, I find AROME ceases to be as good as in a clear situation - also the ARPEGE has a habit of downgrading temperatures by a degree or two within T24, but then being a degree or so too low compared with the final maximums (e.g. on Tuesday it did this). Also, with the ECM unchanged at a raw max of 35/36C, adjusting up by an average of 3C usually gives a pretty accurate result which in this case is 38C/39C.

So to sum up, I think the July record is a given, 40C is now unlikely, and for the UK record of 38.5C, toss a coin.

And thus ends my model predictions for this heatwave - after a good ten days of chasing, we made it to T0 - always satisfying to see a chase come off

[knocker]

A tweet from Matt Hugo

Quote

I'll have a bash at highlighting where greatest storm risk will be. Iniitally could see something over #Wales but IMO, the N Midlands, N England and S Scotland prime locations late afternoon. Incredibly 00Z EC has a +22C theta-w plume over N Eng where the greatest storm risk is.

[Methuselah]

So, the GEFS 06Zs are, like on yesterday's run, still going with a general cool-down of sorts and offer no suggestion of any new plumes? As for today's maxes...they'll be what they are?

   

   

It'll be interesting to see (I think) whether the 06Zs show a re-emergence of scatter?

[mb018538]

Looking like we may have a price to pay for all of the heat this week - huge heat transport into polar regions, which will encourage pressure to rise again. So we are staring down the barrel of more northern blocking into early August, with troughing close by or over the UK. 

Another forgettable August (in a long list in recent years) coming up? Too early to write the whole month off, but the first week isn’t looking too great.

[knocker]

25C already showing on the 0700 UTC chart

 

[Downpour]

1 hour ago, knocker said:

A couple of spot checks from the ecm for the weekend

Interesting. Largely dry west of the meridian in the south. 

[BornFromTheVoid]

A few posts moved to the general summer chat thread. It will likely be a busy day, so lets try keep things on topic and in the appropriate threads. Cheers!

[Frosty.]

The Gfs 0z operational is going for 37c 99f but I think we can add a few degrees to that so make it 39c 102f for the hottest spot (s)...but watch out for severe thunderstorms this evening and tonight moving up from the south..a fitting end to a stunning heatwave!!!..hate it when they end with a whimper, don't think this one will!!!!!!!!!!!!!!!!!!!!!!!

Edited July 25, 2019 by Jon Snow

[knocker]

Latest wrf on convective activity this afternoon

[MATTWOLVES 3]

2 hours ago, mb018538 said:

Looking like we may have a price to pay for all of the heat this week - huge heat transport into polar regions, which will encourage pressure to rise again. So we are staring down the barrel of more northern blocking into early August, with troughing close by or over the UK. 

Another forgettable August (in a long list in recent years) coming up? Too early to write the whole month off, but the first week isn’t looking too great.

Not so sure about this... Firstly the weekend away from the North and East is decent... We have some potentially unsettled conditions early next week, but signs of improvement midweek onwards and warming up again. The extended ecm ens into August show a mean of 9c and pressure around 1012...there is also a fair amount of spread showing its just as likely to be settled, as unsettled. 

Edited July 25, 2019 by Mattwolves

[Downpour]

24 minutes ago, Mattwolves said:

Not so sure about this... Firstly the weekend away from the North and East is decent... We have some potentially unsettled conditions early next week, but signs of improvement midweek onwards and warming up again. The extended ecm ens into August show a mean of 9c and pressure around 1012...there is also a fair amount of spread showing its just as likely to be settled, as unsettled. 

Yes, this weekend is interesting. Looks pretty good west of the meridian and south of the Trent. Next week, fine weather to be had in the east. A developing picture on the models, hence lack of commitment on TV forecasts I would venture. 

[MATTWOLVES 3]

1 minute ago, Downpour said:

Yes, this weekend is interesting. Looks pretty good west of the meridian and south of the Trent. Next week, fine weather to be had in the east. A developing picture on the models, hence lack of commitment on TV forecasts I would venture. 

Most definitely Downpour... Usually when we get this no clear signal scenario, we are more likely to hear the phrase a NW/SE split looks most likely. 

[knocker]

The 0900 UTC Sat image

[Frosty.]

ARPEGE 6z solid for 37/38c 100f covering quite an area and I'm sure within that area there's a good chance of the hottest spot(s) hitting 39c 102f...I wouldn't even rule out 40c!!!!!!!

Edited July 25, 2019 by Jon Snow

[chrisbell-nottheweatherman]

3 hours ago, Ed Stone said:

It'll be interesting to see (I think) whether the 06Zs show a re-emergence of scatter?

Indeed, very little Shannon Entropy in that output.

[swebby]

 

3 hours ago, mb018538 said:

Looking like we may have a price to pay for all of the heat this week - huge heat transport into polar regions, which will encourage pressure to rise again. So we are staring down the barrel of more northern blocking into early August, with troughing close by or over the UK. 

Another forgettable August (in a long list in recent years) coming up? Too early to write the whole month off, but the first week isn’t looking too great.

Tis always a concern seeing a big fat high over Greenland and why i queried quicksilvers post the other day about what was showing for the start of August. 

From a imby perspective, the Azores High has been there of there abouts for a good part of the summer and it has struck me that the models have tended to underestimate it's strength/resilience in the 5-10 day range, leading to better than forecast conditions for the SW and S.England for that time frame.  We have had a relatively subdued MJO for the summer which, as with the AH, is counter to what has been forecast, so this may be related but i'll leave that to those that know more about the teleconnections?

 

 

[Frosty.]

The Gfs 6z operational is a mixed bag, there is some ridging but also some troughs, temperatures generally into the low / mid 20's celsius across southern uk, a bit cooler further north...so, there's some fine warm weather but also showery spells and occasional persistent rain...normal uk summer weather.