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

[Allseasons-Si]

The latest from the cpc anomoly's this evening is as you was from last night,trough stuck out west drawing in plume conditions from the S/SW,the latter more of an unsettled scenario with a possible breakdown from the west but still warm with a SW'ly/W flow

 

we do see temps on a down-slide towards the end of the week but that's miles away in terms of meteorology and we could see this warm/hot spell extend,we know how hard blocks are to shift!

I really hope the gefs mean comes up trumps cos the ecm mean is not as good at day ten.

 

 

Edited July 18, 2019 by Allseasons-si

[Mike Poole]

ICON 18z here at T96:

And here T120, as far as it goes:

Looks to me it's going down the ECM route....

[shaky]

If its of any interest the latest icon has joined ecm at 120 hours!!!atlantic trough backed further west and hot air incoming from the south!!

[MATTWOLVES 3]

Just had a look at the extended ecm ensembles going out to end of July and thought till 2nd August... Basically the mean Is coming in at 7.9c at this point... The highest member was 14.9c and the lowest was 1.9c....wow...that would make  even Feb blizzard proud. 

On Friday the 26th the main run coming in at 23.3c with the mean coming in at 11.3c....thats some difference... 

Edited July 18, 2019 by Mattwolves

[northwestsnow]

2 minutes ago, shaky said:

If its of any interest the latest icon has joined ecm at 120 hours!!!atlantic trough backed further west and hot air incoming from the south!!

Woohooo!!

Any support for EC is welcome, 18z will give us a good idea if EC is in the right ballpark .. 

[shaky]

3 minutes ago, northwestsnow said:

Woohooo!!

Any support for EC is welcome, 18z will give us a good idea if EC is in the right ballpark .. 

I did say earlier that i feel ecm could be the one thats right here!!maybe not as extreme as this evenings 12z run but defo better than the gfs 12z!!

[Downpour]

2 minutes ago, northwestsnow said:

Woohooo!!

Any support for EC is welcome, 18z will give us a good idea if EC is in the right ballpark .. 

Several members disregard the 18z as the pub run. But I dare say many will be interested tonight. If the ECM has support, we could be looking at a prolonged heatwave. 

[MATTWOLVES 3]

9 minutes ago, Downpour said:

Several members disregard the 18z as the pub run. But I dare say many will be interested tonight. If the ECM has support, we could be looking at a prolonged heatwave. 

The Ecm isnt supportive of a prolonged heatwave though.... The mean is down below 10c by months end! I don't think the gfs 18z being supportive in any way will have much baring... The morning runs nearly always play down the 18z run. 

 

 

 

Edited July 18, 2019 by Mattwolves

[Allseasons-Si]

Either way we are going to see summery conditions next week,what the hell with the temps,lets just enjoy it eh

hopefully there will be the added bonus of some severe storms to come with it,a typical British scenario

[Mapantz]

3 minutes ago, Mattwolves said:

The mean is down below 10c by months end! 

The mean is well below 10°C now, but it hasn't stopped temps getting in to the low - mid twenties quite widely today.

[MATTWOLVES 3]

1 minute ago, Mapantz said:

The mean is well below 10°C now, but it hasn't stopped temps getting in to the low - mid twenties quite widely today.

Yes I agree a mean of 8c can bring low mid 20s...but it's not supportive of an extended heatwave... Ie... 30+ degrees. 

[Downpour]

7 minutes ago, Mattwolves said:

The Ecm isnt supportive of a prolonged heatwave though.... The mean is down below 10c by months end! I don't think the gfs 18z being supportive in any way will have much baring... The morning runs nearly always play down the 18z run. 

 

 

 

Sure, but month’s end is an eternity away in forecasting terms. What’s the outlook until 29 July?

[MATTWOLVES 3]

2 minutes ago, Downpour said:

Sure, but month’s end is an eternity away in forecasting terms. What’s the outlook until 29 July?

Most definitely... Alot can change, I agree... And who's to say its not going to be settled... The mean was coming in at 1012mb and there was a fair few runs 1020+mb...so it still looks good regarding lengthier settled conditions. 

[Tamara]

On 17/07/2019 at 17:42, Tamara said:

Final outcome probabilities, in synoptic terms, allows the type of scenarios where cut-off lows result as trough deconstruction occurs, and in the wake of this deconstruction, the sub tropical ridge upstream re-asserts a renewed eastward ridge from within the Equatorial Atlantic to reinforce the existing downstream ridge, trapping that cut-off low beneath the ridging, and potentially sustaining heat ridging in place for longer.

With meandering and sluggish jet patterns, choreographed through a mix of highly unstable tropical and polar forcing, which in turn create destabilised and often disconnected GSDM profiles, heat trapping scenarios are bound to become more regular summer time features it would seem, to me at least as much as implications of various kinds can be drawn for the opposite times of year..

The UK's fate, in terms of tapping into continental increases in heat, rests as usual in the actual wavelength that the sub tropical ridge amplifies. All tied into that primary wavelength dictated by frictional torque tendency within the Pacific, as just discussed according to the controlling tropical wave(s). But also the polar profile determining the latitude the ridging sets up.

This time around, the downstream pattern is allowing trough progression to be able to force greater sub tropical amplification of ridging ahead of it - instead of what occurred in late June when the wavelength favoured earlier retrogressive amplification. 

The ECM 12z operational might be an outlier of this evening, and indeed may prove by next week to have been just that - but it fully exemplifies (to the greatest extreme maximum!) the scenario I outlined yesterday, and which is also present in sections of the FV-3 GFS suite as well.

NWP model suites are simply snapshots in time, and each one develops the themes of the previous suite according to the diagnostic probabilities. So its quite conceivable for even upper air patterns to diverge from one suite to another when an essential part of the jigsaw in terms of the upstream pattern shows a large spread degree of uncertainty. And from memory someone posted a substantial degree of spread of the eastern Atlantic yesterday which illustrated the conundrum of how energy is split with the trough responsible for ushering in the initial (very) warm air advection from the start of next week.

Climatology favours the more progressive solution, and it could be that the expected two/three day plume = fresher air to follow does indeed verify, but I wouldn't personally be astonished to see a curveball. This based on the diagnostic probabilities that suggest and support some deceleration of the jetstream across the Atlantic round about the pivotal time that heat advection is pushing north through the UK. This interfering with the distribution of energy in the eastern Atlantic at the key period - and which leads onto that Atlantic ridge late next week to fill the void left by the slowing pattern to complicate things further and help stall the eastward shunt script. And which is clearly modelled on the ECM 12z as well

The ECM 12z might turn out to be some viewing entertainment in the fulness of time, but as a few have already hinted at, there is nothing about its modelling within the day 4 to 6 period which is not credible - even if the chances of such sustained intense heat as it shows are likely (relatively) moderated. Or maybe not as the case might be...

 

[MATTWOLVES 3]

The Gfs legacy should now be renamed the gfs legend, as it smashes the core of heat right through the uk and quite far North to.... The FV3 only bringing a glancing blow to the SE.... The new kid on the block the party pooper once again... The legacy.... Absolutely Stirling... 

[Man With Beard]

Though the GFS 18z is rarely the most reliable run for some reason, it does seem pretty much down the middle of all the options seen today - heat building until Wednesday, swept away Thursday. 

[Singularity]

Hmm... FV3 18z came a lot closer than the 12z did to the ECM 12z / ICON 18z solution, but didn’t split the trough cleanly enough or have the additional trough into the N Atlantic come into play fast enough.

The mere presence of adjustments closer to it from even the furthest away of the models on the 12z cycle is noteworthy. The ECM outcome doesn’t look quite as much of a wildcard now, especially after those very interesting points from Tamara. 

Trough deconstruction - the buzzword of the next few days...?

 

ECM-style outcome now at 20% odds in my mind. Yikes.

[Downpour]

6 minutes ago, Man With Beard said:

Though the GFS 18z is rarely the most reliable run for some reason, it does seem pretty much down the middle of all the options seen today - heat building until Wednesday, swept away Thursday. 

Indeed, and then the trough to the west fills out. Leaving it dry and settled, but not hot, in the SE by next weekend...

[MattTarrant]

3 minutes ago, Singularity said:

Hmm... FV3 18z came a lot closer than the 12z did to the ECM 12z / ICON 18z solution, but didn’t split the trough cleanly enough or have the additional trough into the N Atlantic come into play fast enough.

The mere presence of adjustments closer to it from even the furthest away of the models on the 12z cycle is noteworthy. The ECM outcome doesn’t look quite as much of a wildcard now, especially after those very interesting points from Tamara. 

Trough deconstruction - the buzzword of the next few days...?

 

ECM-style outcome now at 20% odds in my mind. Yikes.

More a phrase than a word no? 

No on a serious note both the FV3 and Legacy attempt to  deconstruct the trough ECM style. Regarding the N Atlantic trough it seems relevant to notice that the ECM 12z was more amplified initially allowing for the newfoundland trough to aid the pattern transition. 

[Cheshire Freeze]

2 hours ago, Man With Beard said:

The ECM op of the past 3 days has either been in the hottest or the coolest clusters! 

But judging by where cause of the uncertainty lies - namely, the dealing with the Atlantic trough - I think things will start to firm up tomorrow. One needs to also bear in mind - a UKMO/ECM op run combo will usually lead the way at D5/D6. So a very hot Wednesday looks in the lead right now, to me. 

Not sure what is going on with the ECM. It sure doesn't seem to be the model it once was.

I genuinely think people are clutching at massive straws with regards to the 12z ECM DET output. It's so far above its ensemble pack that it really is hard to take it seriously at all. I'm not poo pooing the idea of the trough splitting like that but I don't think if it happens it'll be as clean nor as far west. 

Edited July 18, 2019 by CreweCold

[Captain Shortwave]

So far nothing going with the ECM op, the UKMO looks similar to the 12z. Wednesday very hot but with a front moving east later on into Thursday.

GFS, poor consistency here, it will take two attempts to break the pattern down with Thursday possibly being hot on this run as well.

[northwestsnow]

10 minutes ago, Captain Shortwave said:

So far nothing going with the ECM op, the UKMO looks similar to the 12z. Wednesday very hot but with a front moving east later on into Thursday.

GFS, poor consistency here, it will take two attempts to break the pattern down with Thursday possibly being hot on this run as well.

Yes, cant see much backing for the sensational EC det last night,perhaps to be expected.

That said , at face value UKMO doesn't look great at 144 but the 850s reveal the warm air still in place across the UK.

Are thunderstorms going to be on the menu i wonder.

[knocker]

Outlook - A fairly marked NW/SE split will develop over the next few days

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

Rain from the warm front, including some heavy pulses is already into south Wales and the south west of England and this will spread north east during the day effecting just about everywhere apart from the far north of Scotland. It should clear most places during the afternoon leaving sunny intervals and showers but a wave on the cold front will introduce further rain in the south during this evening. This should clear the south east by the early hours tomorrow but the bent back occlusion will ensure that some rain lingers across the north.

Most of the frontal rain will be gone by Saturday but some heavy showers could well develop which will include thunder in the mix and these will be more prevalent in the north east where remnants of the occlusion still linger and in central areas courtesy of a trough in the southern quadrant of the low.

Over Saturday night and through Sunday the much discussed new upper low has tracked into the atlantic and started to phase with the one south of Iceland resulting in a relatively warm westerly upper flow over the UK and a dry day. But a frontal system related to the new trough is tracking rapidly north east bringing moderate rain and increasing wind to the north west late in the afternoon

By Monday the trough is moving towards a more neutral alignment which promotes amplification of the subtropical high to the east resulting in the surface wind backing a tad and warmer air to encroach from the south  But frontal systems and rain are still effecting the north, along with quite strong winds.

The trough is more or less neutrally aligned by Tuesday with the surface low 997mb to the west of Ireland and the associated cold front bringing rain there during the evening. But a trough has also developed over northern France which results i rain in the south during the evening. The movement of the upper trough to the west has facilitated advection of warm air so wuite a warm day for most

 

Edited July 19, 2019 by knocker

[Polar Maritime]

UKV take on Mon/Tue temps.

[knocker]

The movement of the upper trough and energy distribution, and subsequently the ridge, are paramount of the next couple of days and according to the gfs it goes like this

Thus on the surface frontal activity and cooler air will push slowly in from the west with the possibly of a classic Spanish Plume scenario whilst the south east remains very warm

Edited July 19, 2019 by knocker