Model Output Discussions 12z 03/05/2016

[knocker]

Today

Drier and much less windy than yesterday for most but a band of rain will track NE from the west later.

The GFS this morning

By Tuesday the UK is in the circulation of an HP cell that has moved east, apart from NW Scotland where some rain is still lingering, so dry and quite warm in England. The slack unstable LP is in the Biscay area with the main low south of Iceland.

The aforementioned Biscay low tracks NE through Weds/ Thursday bringing some thundery outbreaks to central, southern and eastern England. Temperatures for the two days could reach 30C SE of a line Tyne to Bristol on Weds and East Anglia on Thursday.

The unstable area continues NE to be replaced by a transient ridge with a front associated with a shortwave that has developed in the southern circulation of the Atlantic low arriving just to the west by Saturday. This front fizzles out allowing ridging once again from the south west. This would portend a dry, not Scotland, weekend with quite warm temps in the usual area. But at this stage I'll treat this with grave suspicion certainly until the ecm appears

 

 

 

Edited August 21, 2016 by knocker

[Matthew.]

The ECM doesn't look bad for bank holiday weekend, seems reasonable weather with a ounce of breeze and bright enough. I'll let others go into detail though.

Edited August 21, 2016 by Matthew Wilson

[knocker]

The ecm tracks the developing low from Biscay NE on Thursday and there could well be some quite intense convective activity associated with it and some quite big localised rainfalls. Temps in the usual area could be up to 30C for Weds and Thursday but the passage of the unstable low signals the end to the localised hot spell with cooler air behind it with temps around average.

Having said that as the low pressure moves away into Scandinavia the Atlantic low tracks east and dissipates over Scotland leaving the UK in a very slack pressure area for the weekend portending dry, unless a little perturbation running east effects the south, weather with around average temps.

[Captain Shortwave]

So the brief hot spell midweek.

      

Again up to 30C on Tuesday, low thirties widely across central/southern England on Wednesday perhaps. Thursday looks uncertain still with regards to potential heat with the position of the cold front being key to whether it is hot and sunny or wet, a huge contrast in temperatures. One thing I would say is that the temperature forecasts from this and many other models seem to be higher or indeed much higher than the BBC forecasts which continue to suggest that the 30C mark will not be breached which is a little bit of a head-scratcher, especially as Tuesday and Wednesday in particular look sunny across a large area of England at least.

As for the bank holiday weekend, well the big 3 for Saturday.

      

Fair to say that the GFS and UKMO have a similar idea in building a transient ridge towards the east of the UK with low pressure to our west, the ECM looks flatter with shallow systems running along the jetstream, so the ECM would likely be cooler and wetter during the weekend. The GFS/UKMO would deliver some warm or very warm weather before the trough moves through later in the weekend, the ECM however would see near normal temperatures for all. 

[knocker]

I see the ecm is still developing 99L and curving it north. There would appear to be a huge amount of uncertainty regarding the development at the moment.

[Cloud 10]

15 minutes ago, Nouska said:

GFS 06Z having fun and games with invest 90L and goes stir crazy with activity in the Atlantic.

blob:http://www.tropicaltidbits.com/a69aee2e-121d-4dc5-9a62-89f356d7d746

Edit - not sure why gif is not a live link but works if copied and pasted.

 

 

 

 

Yes,that TS certainly not doing us any favours on the 06z around day 10 by driving heights towards Greenland,and adds insult to injury by the end of the run!

 

[Nouska]

Finally worked out how to do it.

GFS 06Z having fun and games with invest 90L and goes stir crazy with activity in the Atlantic.

[MP-R]

49 minutes ago, Cloud 10 said:

 

Yes,that TS certainly not doing us any favours on the 06z around day 10 by driving heights towards Greenland,and adds insult to injury by the end of the run!

 

That's quite the autumn storm! Looks similar to the one on 11th-13th September 2011.

[Polar Maritime]

4 minutes ago, Nouska said:

Finally worked out how to do it.

GFS 06Z having fun and games with invest 90L and goes stir crazy with activity in the Atlantic.

Even more uncertainty as we head into Autumn with such charts Nouska, A very lively Altantic indeed which should make for interesting model viewing over the coming weeks.

[Man With Beard]

Looking at the 12Z charts ... 90F very much under threat at just T72, much of England and Wales look set for a hot few days, less so further N and W.

...and I'm beginning to wonder if there will be a round 2 at the weekend? Both GFS and UKMO have a further slight dig of the upper trough to our SW at the end of the week, and it could prove enough to push further hot weather from the south.

[knocker]

We continue with the thundery low  tracking quickly NE on Thursday, perhaps some quite interesting weather, and thereafter a cooler regime with nearer average temps. With the  upper trough so orientated a bit of a N/S split over the BH with the south probably benefiting from some ridging from the Azores.

[Matthew.]

6 hours ago, Cloud 10 said:

 

Yes,that TS certainly not doing us any favours on the 06z around day 10 by driving heights towards Greenland,and adds insult to injury by the end of the run!

 

Let's seriously hope heights fall over Greenland. Apparently very warm water around Greenland might help encourage a more northern track.

[Summer Sun]

10 minutes ago, Matthew Wilson said:

Let's seriously hope heights fall over Greenland. Apparently very warm water around Greenland might help encourage a more northern track.

12z has it closer to Iceland

[Matthew.]

1 minute ago, Summer Sun said:

12z has it closer to Iceland

An exciting September ahead! If the 12z is correct we could end up pulling a lot of warm air up from the south from upcoming TS's. All will be revealed

[knocker]

You couldn't make this up regarding next weekend. The ecm tracks the thundery low NE through the UK Thursday/Friday and it becomes quite an intense feature as it heads towards Norway. This leaves the UK in a very slack pressure area on Saturday but at the same time it has developed a little low in mid Atlantic which tracks east and is incorporated in a slack area of low pressure to the south and then pushes a rain belt north over the south on Sunday. I don't believe a word of it.

 

[knocker]

45 minutes ago, Summer Sun said:

12z has it closer to Iceland

And at the moment

 

[Captain Shortwave]

So here are the charts for midday Friday from the GFS/UKMO/GEM/ECM

   

   

To be honest given the differences I would say that the bank holiday weekend is still up for grabs in terms of the conditions, it could be hot, dry, wet or cool at the moment. 

[Man With Beard]

26 minutes ago, Captain Shortwave said:

So here are the charts for midday Friday from the GFS/UKMO/GEM/ECM

   

   

To be honest given the differences I would say that the bank holiday weekend is still up for grabs in terms of the conditions, it could be hot, dry, wet or cool at the moment. 

If conditions go in a certain way, I can see the SE registering 30C on several days by the end of next weekend. Odds against, but you can see how a fresh burst of heat could develop. Would be nice to have a summery bank holiday to finish off the summer.

[knocker]

The EPS tonight doesn't suggest to me a hot BH although the SE might hold on the some of the heat before the complete transition.

The pattern continues to become less amplified with a gradual weakening of the ridge east and similarly the warm plume. Thus the upper flow veers and the trough becomes more influential tending towards the usual N/S split. The GEFS is not dissimilar.

[knocker]

The GFS this morning

Wednesday 18z sees the UK in a very slack pressure regime with the Iberian area of low pressure pushing NE into England and the main Atlantic depression still south of Iceland. During the next 30 hours the influence of the Iberian low extends further north bringing showery, thundery outbreaks, before moving into Scandinavia by midnight Friday. Through Friday there is briefly some ridging before another tracks east and phases in with further developments in the Iberian region which result in another unstable LP area travelling north and bringing further showery outbreaks for the BH weekend. Not dissimilar to what the ecm was hinting at last night that I cavalierly dismissed. Thereafter it's morning Atlantic but that can keep.

Meanwhile in the interim some quite warm temps Tues-Thursday. Tuesday quite widespread in England and max around 28C in places, Weds not quite so widespread but could reach 30-32C in places and Thursday could see 32C in the east/south east.

On hearing the latest Sidney nipped to the cool of the canopy

 

 

Edited August 22, 2016 by knocker

[Paceyboy]

Seems 00z GFS and its ensembles keen to keep the 15c 850 temps well into the Midlands until Thursday evening. Renewed push for a day or two on the weekend for some more heat starting to appear. 

 UKMO looks similar but obviously we can't see 850s.

 

ECM not loving the heat that much.

Edited August 22, 2016 by Paceyboy

[knocker]

3 minutes ago, Paceyboy said:

 

ECM not loving the heat that much.

I'm not sure I follow that unless you are averaging it out over the whole of the UK and N. Ireland. It is broadly similar to the GFS with 28C possible over much of England on Tuesday.and 30c SE of a line Humber to Bristol (more particularly down in the SE) on Weds and Thurs.

[knocker]

The ecm is broadly similar to the GFS until the end of the week. It doesn't move the Atlantic low quite as far east as the gfs but it does develop the unstable low over Iberia and move it north on Saturday bringing some showery, thundery outbreaks. It diverges from the GFS from then on by tracking quickly east, leaving the UK in a very slack pressure area and giving a much drier day on Sunday

[coldcomfort]

Still plenty to be resolved re detail across the working week......however what it ultimately boils down to is plenty of warm/very warm weather for most of England, but the far west of the country, along with much of Scotland, Wales and N Ireland look set to miss out on any heat (and in some cases even any warmth) once again. As for the BH weekend, still far too early to call with any confidence, but if there is to be any dry, warm and settled weather on offer it's looking increasingly likely that only the SE of England will see it, with 80-90% of the UK having to endure further distinctly average weather.....as per the summer in general.

Edited August 22, 2016 by coldcomfort

[Man With Beard]

The desire for a second round of heat on Saturday has gathered pace quickly

Note some runs in there that keep it very hot for 3-4 days without a break. I'm pretty sure the hottest runs would see us up to 35C/36C. 

As it is, I expect the ECM would get close to 32C, the GFS would exceed 32C, and the GEM saves it for Saturday when it could reach 35C