Model Output Discussions 12z 03/05/2016

[MP-R]

Liking the GFS 12Z - model watching gets that bit more interesting into September with these tropical/ex-tropical features. Reliable timeframe looks a bit changeable, and August's weekend curse looks set to continue into this weekend, but the first half of next week would return warm settled conditions before a thundery easterly sets up with low pressure moving up from the south, to later be absorbed by the Atlantic low and then back to square one. Wouldn't mind that evolution if it came to pass. Could do with a thunderstorm here - the GFS's outcome would bring a September 2014 storm here.

[Singularity]

3 hours ago, Nouska said:

The IMO site has 6 hourly means for the 15 days covered by the ensembles. It only covers part of the British isles for 850 temps but from what I see of the 00Z run, the peak of the plume is at +138 hours.

It's all looking pretty good out to the end of the run and based on this I've put in a high CET guess next door.

Thanks Nouska, that's an excellent resource to add to the bookmarks 

The 12z runs appear to have reverted to the consensus of several days ago, with a strong ridge being driven NE ahead of a large amplifying trough. That's what happens when it all comes together nicely... and to be honest I'd take that over a brief but intense plume as I've quite had enough of storms romping away all around me without once paying me a visit. Well, that and it would make for a nice easy forecasting week .

In the 12z GFS det. run, 29*C appears in my area on three days in a row 8th-10th. In 2006 I can only recall the temp. climbing that high on a single day!

[knocker]

The 6-10 anomalies tonight are all in the same ball park, as were the GEfs and NOAA last night, with the trough far enough west to allow the Azores to ridge NE which tallies quite nicely with the det runs. So some good, dry and quite warm weather next week. How long it lasts is of course open to question and the ecm is partially breaking it down quite quickly post day ten but that will keep. I'll take a few good days as a bonus.

Edited August 31, 2016 by knocker

[knocker]

Today

A mainly fine day in England and wales but rain will creep into the NW and Scotland later.

The GFS this morning

After an unsettled weekend with rain/showers/sunny periods hp builds to the east starting Tuesday but by Thursday, as the pattern edges slowly east, it has split the upper trough to the west forming a cut off upper low to the SW. This facilitates the formation of shallow surface lows to form and travel north and although the easterly influence from the HP hangs on for a while this opens the door for Atlantic fronts to make inroads by the weekend.

EDIT

Having just looked at the GEFS anomaly I'm taking this run with a large dose of Saxo. One thing worth noting is the very dry spell for the S/SE looks set to continue a while.

Edited September 1, 2016 by knocker

[Man With Beard]

UKMO/GEM/GFS all gave slight variations on the pattern for next week, but all come up with the same result - very warm and sunny for almost all of the UK. Mid to high twenties possible every day next week, and not just in the SE.

Whilst the upper trough remains to the west, there'll be no end in sight to summer. Last night's NOAA allows for hot bursts all the way to mid-September:

the upper trough a little close for comfort in the N and W but with higher pressure to the east the wind direction can only come from a limited number of ways, and they're all warm.

Edited September 1, 2016 by Man With Beard

[Captain Shortwave]

Day 5 charts from the GFS/UKMO/ECM

      

Pretty good agreement here, the GEM is pretty similar to these three as well so it does look like high pressure will build across the UK and central/northern Europe at the start of next week. The question is how this high evolves, do we see a plume event or a more substantial and widespread settled and warm spell develop. 

Day 6 

      

So high pressure centred to the east of us is agreed on, but how the trough to our west sharpens and potentially becomes cut off is the issue and hence how long the high hangs on for before we see a potential breakdown from the west. There is certainly the potential from all three models to see the 30C mark reached next week which is pretty good going for September.

Edited September 1, 2016 by Captain Shortwave

[mb018538]

Looking good again today - heat perhaps not quite as 'extreme' as was shown yesterday, but still hot for September, with a 30c not out of the question. If only it was July eh

[knocker]

I might have been a bit hasty earlier. The ecm is taking the same route as the GFS next week, except it doesn't have a cut off upper low but a negatively tilted trough. Same result, a shallow area of LP traveling north which is a gateway for Atlantic fronts on Saturday swinging up from the SW but it does reestablish HP ridging from the SW by the end of the run although I have to say there is no comparison between the surface analysis at T240 and the 500mb anomaly.

Edited September 1, 2016 by knocker

[Summer Sun]

The high which looks increasingly likely next week edges away towards the end of next week - just in time for the weekend surprising isn't it....

As we move into WC 12th the high starts to rebuild

Before... yep you guessed it - it edges away just in time for the weekend...

[carinthian]

Morning all. The UKMO office chart for Sat Morning looks about right. Beyond that, I think the computer model may have difficulty in timing of rainfall advancement. The problem as I see it is the warm advection thrown up ahead of Gaston as it engages the increasingly powerful jet stream. Maybe enough energy to stir things up and buckle the jet and cause a problem with timing of  frontal activity. So certainly potential for a spanner in the works regarding rainfall timing and location, but probabaly safe at this stage the far Southwest ,Wales , SW Scotland  & Northern Ireland to get rain and wind. Would not like to forecast beyond 48 hours at the moment.

 C

[Man With Beard]

I'm still keeping my eye on the heat over Iberia. These kind of charts would break all-time records down there, let alone September ones - many of these all-time records were set in 2003. These are the last two runs from the GFS.

  

and I really don't think the GFS 06Z is a million miles away from wafting it northwards

bit of a straighter line south to north needed, sustain it for 48 hours, get the heat trapped in an Iberian low "special" and bingo!

There may be one or two very interesting ensembles coming up!!

[Faronstream]

5 hours ago, Summer Sun said:

The high which looks increasingly likely next week edges away towards the end of next week - just in time for the weekend surprising isn't it....

As we move into WC 12th the high starts to rebuild

Before... yep you guessed it - it edges away just in time for the weekend...

I don't really agree with the models, the chances of a warm heatwave now are under 40%, the low pressures over the Atlantic will dominate from now on

[cheese]

4 minutes ago, Faronstream said:

I don't really agree with the models, the chances of a warm heatwave now are under 40%, the low pressures over the Atlantic will dominate from now on

Can we have access to that crystal ball of yours?

[phil nw.]

Will be closing this thread shortly so maybe hold off posting for a few minutes until an new thread is opened..

Cheers.

[phil nw.]

Ok new thread is now open here

This thread is now locked.