Model output discussion - first hot, thundery plume of the summer

[Frosty.]

Looking at the GEFS 6z there's a chance of a scorcher during the second half of next week..could be very interesting next week!

Edited July 15, 2019 by Jon Snow

[Methuselah]

Well...if a muggy night's the price of a drop of rain, I'll take it.

   

[Frosty.]

Ok now for the 12z runs, firstly the ukmo 12h, any potential heat next week is beyond its range currently but there's a bulge of height rises from the azores just to the south of the uk at day 6 so days 7,8 and 9 would have been very interesting, as for the ICON 12z, well that goes a bit further and indicates some continental warmth / heat pumping north across the S / SE further into next week.

[Singularity]

 

A leap by FV3 toward the flatter solution of the ECM 00z out to the start of 22nd - but not as intense and progressive with the Atlantic trough.

So, it's a slower route to building hot weather across the UK, but it could do so more sustainably than the 06z did, if the trough amplifies enough.

As of +216 it's got more of that than the 00z ECM gave it, maybe enough for at least 3 days in the high 20s to low 30s (allowing for the usual underestimation by the raw numbers)?.

Will need at least 4 to 'beat' the 06z for duration and at least one 34*C from the raw numbers to do so for peak intensity too.

[Singularity]

3 hours ago, Man With Beard said:

The EC clusters indicating a good chance of the second plume of the summer. Weak trough directly to the west, stronger ridging to the SE, as strong as it has been this summer - much more likely to ensure a S of W flow at all levels than the end of June set up had. This chart below is just D8 so we could see a firming up in the models quite quickly (or not, of course!) 

Somewhat surprised to see the ridge then find a home to our near-NE considering the evolution over the previous few days of the FV3 12z.

An easterly surface flow here, and it was almost a north-easterly! Sometimes it's as if the models have a sense of humour .

Could hardly be further apart from the ECM 00z across Scandinavia. The models have been frequently disagreeing over that region for a little while now. Intriguing.

[summer blizzard]

Just now, Singularity said:

Somewhat surprised to see the ridge then find a home to our near-NE considering the evolution over the previous few days of the FV3 12z.

An easterly surface flow here, and it was almost a north-easterly! Sometimes it's as if the models have a sense of humour .

Could hardly be further apart from the ECM 00z across Scandinavia. The models have been frequently disagreeing over that region for a little while now. Intriguing.

It looks to me like the GFS output is quite unstable right now, especially past day 10.

In recent days it forecast a resurgance of the westerlies east of the dateline (hence some juicier long term runs) however as of today it has switched to putting convection over the Indian Ocean with a superimposed MJO wave coming out of 2 into 3.

[Methuselah]

Very plumescent: almost getting the 20C isotherm into Southern England.

   

[Polar Maritime]

Yes Pete, All academic at this range re temps, But at a glance low 30s in the S/E very warm elsewhere and record temps for parts of Europe again maybe?

Edited July 15, 2019 by Polar Maritime

[Frosty.]

Even the Gem 12z introduces a pulse of very warm / hot and humid continental air and potential thundery activity towards next midweek across the S / SE for a time..in the meantime, there's some welcome rain expected for the parched gardens of the south later this week.

Edited July 15, 2019 by Jon Snow

[Frosty.]

There's quite a lot of support from the GEFS 12z for an influx of very warm / hot and sultry continental air as we go further into next week, at least across southern uk..interesting mean!!

Edited July 15, 2019 by Jon Snow

[Tamara]

1 hour ago, summer blizzard said:

It looks to me like the GFS output is quite unstable right now, especially past day 10.

In recent days it forecast a resurgance of the westerlies east of the dateline (hence some juicier long term runs) however as of today it has switched to putting convection over the Indian Ocean with a superimposed MJO wave coming out of 2 into 3.

If I might interject here

The lack of MJO forcing in the Pacific, with emphasis of activity sticking in the I/O, is being dampened/offset by the low frequency signal which remains firmly in the Pacific- and a reminder to us all that the MJO is not always the be all and end all when it comes to pattern change dictation from the tropics.

Its early days, but there are some similarities developing with the latter part of the summer in 2016 developing. That is not to say it is going to pan out exactly the same as the second part of that summer, but a Pacific low frequency wave train is present at this time as it was then.  These persisting westerlies showing up orange shaded close to the dateline here:

 

The latter part of summer 2016 and indeed well into September produced a re-cycling pattern of plumes interplaying with eastward displacing Atlantic and Azores ridging that alternated cooler more unsettled phases with these warmer plumes.

The prominence of the low frequency signal is echoed by the SOI (Southern Oscillation Index) which ironically is more -ve now than at any time this year that an Nino SST signature has been present in the Pacific (SST's overall now trended neutral - warmest to the west, coolest to the east)

 

 

So despite the fact that angular momentum has slipped to levels not seen for over a year c/o loss of westerly momentum in the extra tropical circulation (and is also at a similar level to late summer 2016), the weak walker cell circulation and associated convective convergence zone is still enabling something of a downstream synoptic response that is more reminiscent of El Nino than the extra tropical wind-flow Global Wind Oscillation might suggest.

Hence the ability for some a-typical sub tropical ridging downstream, as a reprieve from occurring too far upstream and allowing a UK trough dominating instead as one might expect from a lower AAM extra tropical response.

Its still only mid July, and clearly still rather early to say for sure, but this tropical forcing disconnect, if it can prevail/re-cycle may yet produce a better second half of summer, than the increasingly Nina'ish extra tropics implies

Much as happened in August/September 2016.

 As long as the western/central Pacific walker cell circulation keeps producing convergence close to the daleline (as it encounters countervailing trade winds c/o divergent/stable relatively cool waters in the Southern Pacific) then there is no automatic assumption to be made that a more typical Pacific/.Atlantic Nina-esque circulation should take over (such as it did after mid July in 2017 as a good example) and which resulted in a retracted Atlantic ridge with enhanced polar flow and troughs steered close to the UK.

Edited July 15, 2019 by Tamara

[Methuselah]

Well, the 12Z GEFS ensembles are nae bad; barely anything drops below 5C at 850hPa.

   

   

And there's still not much sign of either a negative NAO or HLB. Thank Deity of Choice!...

[Djdazzle]

1 minute ago, Mattwolves said:

In the words of Paul Daniels... Your gonna like this.... Not alot!!! Well I actually like this quite alot... 

Now that’s magic . . .

[Frosty.]

I really like where the Ecm 12z operational is heading, still 2 frames to go!

[Singularity]

Quality from Tams as usual - atmospheric disconnect from the ocean doesn’t always work against us

ECM putting out yet another extreme solution I see. It really seems to have a thing for making huge and/or intense troughs whenever there’s a lot of heat on the warm side of the boundaries.

D8 looks to be setting up an absolutely roasting D9+ but I must say, I doubt the trough will be as vast yet organised - hence efficient at piling heat into Europe - as this model keeps depicting.

[Wilxy]

Just now, Jon Snow said:

I really like where the Ecm 12z operational is heading, still 2 frames to go!

Its still decent at 192h!

[northwestsnow]

Blimey, EC turning on the blow torch this evening!!

Edited July 15, 2019 by northwestsnow

[Wilxy]

Wow! Would be perfect timing for my week off work if this pays off!

[northwestsnow]

By day 9 the uppers are hot hot hot!

[Methuselah]

2 minutes ago, northwestsnow said:

By day 9 the uppers are hot hot hot!

Watchout Heathrow!

[northwestsnow]

Hotter still by day 10 !!

Jeez i'm of work end of July i hope it sticks around!!

Edited July 15, 2019 by northwestsnow

[knocker]

Leaving aside the short range until the morning the ecm at t144 has the Atlantic trough dominated with the UK in a showery south westerly with the Frid/Sat front well away to the east

By t168 the next low has arrived NW of Ireland with associated fronts bringing rain and quite strong winds to the vountry

By t192 a fair bit of amplification has occurred and a strong south westerly jet is tracking across the UK between the trough digging south and the subtropical high ridging north east  Quite breezy in the UK with showers in the west. This of course subject to change with later runs

 

Edited July 15, 2019 by knocker

[Frosty.]

Boomtastic Ecm 12z operational..feels like my enthusiasm about the warm up for the last several days on the longer term GEFS mean may have been worthwhile!!..low to mid 30's celsius for parts of the s / se later next week if this is anywhere close!!..bring it!!!!

Edited July 15, 2019 by Jon Snow

[Captain Shortwave]

Hmm no real plume set up there (lack of low pressure towards the Bay of Biscay). However the ECM run is getting close to the sort of set up we experienced in August 2003 with that heat dome expanding northwards. Probably overplayed given the other output though and the thought of glancing blows of very warm/hot weather is more realistic.

Edited July 15, 2019 by Captain Shortwave

[Big daddy 49]

22 minutes ago, TomW said:

Wow! Would be perfect timing for my week off work if this pays off!

Please tell me this goes through to August 10th.PLEASE!.