Model Output Discussion - 30/6/2014 Onwards - Covering July.

[Captain Shortwave]

Well even the less amplified GFS solution has temperatures reaching around 30C

 

The ECM on the other hand would bring widespread temperatures in the high twenties across most of the UK with temperatures probably hitting 90F in places

 

Still disagreements at the day 4 stage with respect to the handling of things upstream and hence the amplification of the Euro/Scandi ridge. The ECM has been very stubborn with this solution and again can it be way off the mark at that timeframe?

 

Week 2, well we see the initial troughing to our west relinquish it's grip from over Iberia with the Azores high trying to build back in

That would probably explain why there is little talk of a major cool off into week 2 from the metoffice as this set up would still bring above or well above average temperatures for many, especially the ECM solution. 

[IDO]

Again this morning ECM is the most amplified, so dragging in the warmer uppers and lasting the longest. The GFS op has moved very slightly towards ECM (as has GEM) as the models sharpen up on the Atlantic Low as it heads SE towards our locale. The long wave pattern seems confident in that respect for next weekend however the amplification from the ECM appears to be due to the difference in how they handle the energy in the next trough.

 

GFS and GEM keep the upper low to the west of Ireland and it's the short wave that brings in the disruption:

 

 

 

Where as ECM stalls the upper low and the adjacent ridge is amplified towards Scandi so when the next rush of lower heights from the Atlantic arrives the Scandi/Euro ridge is strong enough to hold its ground a few days longer and the synoptics change; a more N/S split than the NOAA UK trough at T240:

 

D6  D10: 

 

The GEFS have the op and Control is the main cluster but there is varying support for something similar to ECM.

 

Looking further into GFS FI it does not look too bad, especially the further south you are. No sign of washouts with mean average uppers for most south of the M62 with middling mean pressure:

 

T300 mean  London ENS: 

 

Looking like a very warm to hot spell for many in England and Wales for Wednesday to Friday.

 

 

[johnholmes]

below are my rough notes this morning summing up the 3 main anomaly charts

 

Sun 13 jul

Ec-gfs

Only ec again and it seems to follow the 6-10 ideas of the last few days from noaa, that is +ve heights and ridging over central Europe into Scandinavia and then towards Greenland, ec showing a flatter type of trough than noaa does but both going with the idea of an atlantic flow from states to the trough.

Of course the sharpness and position of the trough is all important to what will happen at the surface in the UK region. Personally I would back the noaa version. It does over the years seem to end up closer to the actual 500mb flow than ec does but not always. 

Both do show a similar slack pattern between Iceland and the far n of the UK/Faroes area.

Sun 13 julSun 

[Bristawl Si]

Hasnt the generally fine spell been forecast to end for a while now?

But actually has not ended

[MP-R]

Good point, Bristle Boy.

 

Quite a mixed bag from the GFS this morning. Warm to hot until the 18th, unsettled briefly over next weekend, then increasingly warm again until the 24th, unsettled again over the following weekend, with another push from the Azores High by the 28th. All FI of course, which starts probably on Thursday but certainly nothing outrageously bad from that model.

 

The ECM only goes out to the 23rd but follows a similar route with a more summerly looking low for next weekend rather than the cool autumnal one progged by the GFS. Again, pressure rises into the new week with the south clinging on to drier and warmer conditions compared to the north.

[Summer Sun]

Pretty much the same as we've had for a number of runs now from GFS with Wednesday to Friday showing the first proper heat of summer building for England and Wales

 

Could be looking at highs around 29c on Wednesday in parts of the south low to mid 20s elsewhere

 

 

Thursday the heat really builds every chance of 30c in parts of the south widely in the mid to high 20's for England and Wales

 

 

By Friday the hottest temperatures are in the south with temperatures into the low 30's temperatures slightly lower the further north you go

 

 

By Saturday the east hangs on to the warmth with temperatures still reaching the mid 20's for some fresher in the west

 

 

Fresher for all by Sunday with temperatures in the high teens / low 20's temperatures just make it into the teens for parts of NW Scotland

 

[Captain Shortwave]

The GFS has gone about half the way towards the ECM solution, finally seeing some troughing west of the UK at the end of the week as opposed to the flatter solutions it has chucked out recently.

Still a little quicker though hence the temperatures are a little lower due to cloud cover and the risk of thundery downpours just about anywhere.

high 20s for Friday but the humidity will be through the roof s it will feel pretty oppressive.

Hmm

Interesting end to the week as this could go bang big time. The warmth and storm risk lasting into Saturday.

Edited July 13, 2014 by Captain shortwave

[Milhouse]

The ECM mean at day 10 has a lot of promise for a second plume event. Pressure lowest around Iceland, not making advances towards the UK. Pressure generally higher over Scandinavia and central Europe. Just what is required for a second hot spell, or at least a settled spell across the southern half of the UK.

 

[stewfox]

 

high 20s for Friday but the humidity will be through the roof s it will feel pretty oppressive.

Hmm

Interesting end to the week as this could go bang big time. The warmth and storm risk lasting into Saturday.

 

Don't often post here just like to read and learn. So what is the above graph showing ? 

Edited July 13, 2014 by stewfox

[Biggin]

Don't often post here just like to read and learn. So what is the above graph showing ? 

Cape and Lift Index, that one shows v good potential for thunderstorms and thunderstorm creating conditions.

[shaky]

Gfs seems to be showing what the ecmwf has been showing over the past couple of days. .......A PLUME!!!about time cos it was really stubborn in showing a flatter pattern!!ecm has really stuck to its output over the last few days!!

[gottolovethisweather]

 

The ECM only goes out to the 23rd but follows a similar route with a more summerly looking low for next weekend rather than the cool autumnal one progged by the GFS. Again, pressure rises into the new week with the south clinging on to drier and warmer conditions compared to the north.

 

Yep, maybe the odd GFS run in isolation at T+168 hours onwards is showing a cooling-off to near normal temperatures by next weekend but the ECM and other suites would be the ones to trust IMHO. I am imagining any fresher weather, at least in the Southern section of England will be a brief event now until the extreme depths of FI. The heat is on and the Air Coolers and Air Conditioning will be needed for a upcoming prolonged spell of high humidities in my view. Bring some Thunder and Lightning to the mix and I'll be a happy bunny. Some sleepless nights ahead for a fair few of us come mid-week and beyond.

Edited July 13, 2014 by gottolovethisweather

[gottolovethisweather]

The ECM mean at day 10 has a lot of promise for a second plume event. Pressure lowest around Iceland, not making advances towards the UK. Pressure generally higher over Scandinavia and central Europe. Just what is required for a second hot spell, or at least a settled spell across the southern half of the UK.

 

 

Precisely how I see things developing in fact, a three day hot spell then a thundery breakdown and after next weekend when it'll only get down to near normal Temps for most, a reload of the suggested pattern. Any cooler weather is looking short-lived as can be expected from traditional spells of UK heatwaves at this time of year.

[IDO]

Looking at the ECM op compared to its members with respect to temps for London suggests that the op is probably overdoing heights again at D9 and D10:

 

The op over 3c higher than the mean on D10.

 

The rainfall totals for the mean is twice as much as the op at D10, again suggesting the op is probably progressive with a further rise in pressure.:

 

 

However the GEFS have also been shortening the returning trough longevity for next weekend, see 06z run, so cannot discount.

 

Looking at how the models handle the breakdown, the ECM D5 members (here) have just under 50% forming two clusters going with the GFS/GEM 0z run of a short wave or daughter low disrupting rather than the core upper low of the ECM op (rest of members including control support op). Compare that with about 66% of members going with the short wave on the GEFS (06z). So still some uncertainty remaining for how the breakdown occurs.

 

 

[Duane S.]

Not much interests me in the summer months the potential for this coming weekend certainly does. I'm going to be watching developments with interest as the heat builds from midweek and instability increases heading into the weekend. Could be one to remember even without those extreme (for the uk) projected cape values occurring.

Edited July 13, 2014 by phil nw.
comment re origional deleted post removed origional pos

[A.J]

IMHO, given the setup modeled, high surface based CAPE charts are quite likely IMO as over the next few days, with a ridge of high pressure in situ, this will result in fairly strong capping in both the surface layers & mid layers for a good majority of England & Wales.

 

The mid-level capping will result in a high degree of conditional instability as the surface CAPE builds as we move through the week. 

 

The GFS (and in my eyes the ECMWF) models then prog a thundery low to develop late thursday over northern Spain and France throwing up a series of shortwave troughs northwards within a  high theta-e value airmass. This series of troughs will lower heights to the south west and allow the capping to erode acting as a trigger to release all the built up convective energy.

 

As ever, more runs needed, but from my perspective, the setup modeled is a classic plume very similar to 27-28/6/2012 which in that instance resulted in values of over 2000 j/kg of both surface and mixed layer CAPE

Edited July 13, 2014 by ajpoolshark

[Milhouse]

By day 10 the GEFS 6z mean has pressure on the rise. Further support for more settled conditions to push up from the south after the weekends unsettled spell. Gone is the low pressure over Europe that will most often give less than favourable conditions for the UK as it inhibits the ability for the Azores high to build in.

 

[knocker]

My post above wasn't suggesting it would happen but  I'm afraid I dislike definitive dismissal without reason. Anyway as been mentioned there is certainly a possibility of strong convective activity with the scenario below and given the dew points are forecast in the mid 60s to 70s.

Edited July 13, 2014 by knocker

[Polar Maritime]

The bottom chart won't materialise.

 

A little reasoning behind these sorts of one liner post's would be helpful in the future.

 

Many Thanks. PM 

[Mokidugway]

Possibly the ever eastward progression of plume events as it gets closer ,till at best they are a Kent clipper ?........

[A.J]

Does anybody still have any of the CAPE/LI charts from 28 June 2012 and 23 July 2013 so we can compare with those?

Hi Scott, can't find archive charts, but here's a snippet of a post from our NW Chief tornado chaser Paul Sherman for 28/6/12..

 

"Very Impressive set of parameters for the Uk and something I spoke with Nick F About whilst chasing 3 weeks back. Had a hunch the Uk would see a Set-Up like this for 2012.

If these parameters were in front of the SPC I am sure a low end Moderate or High end Slight Risk would be on the table right now.

Somewhere from N Cambs through Lincs upto the Humber could very well see a Strong Tornado should a Supercell develop today, good upper flow (enough for a Supercell at 30-35kts) is present, decent Cape of 1,750jkg and very good LCL's all there. Add into that a possible 82/70f around those parts and you have the ingredients for something impressive.

Good luck to all who go out there and remember Storm Motions could be quite fast so position accordingly.

Regards

Paul S "

 

 

To save going off topic, here's the link to the convective thread for that day to read at your leisure, enjoy!   

http://forum.netweather.tv/topic/73690-uk-convective-general-discussion-forecasts-27th-june-2012/page-15

Edited July 13, 2014 by ajpoolshark

[Dan the Man]

A little reasoning behind these sorts of one liner post's would be helpful in the future.

 

Many Thanks. PM 

 

My apologies, however CAPE values in the 2000s+ are unlikely to materialise, especially in the areas predicted. That is not far from being "off the charts"; conditions that would spawn a severe thunderstorm outbreak and possibly strong tornadic activity. Having just been on the other side of the world (and "fortunate" enough to have had a tornado warning) in conditions are far more likely, its still extremely hard to pin down severity until about 24-48 hours before and even then there are downgrades.

 

That said, values around half that would provide quite a lively light show anyway.

[Bobby]

Does anybody still have any of the CAPE/LI charts from 28 June 2012 and 23 July 2013 so we can compare with those?

 

Here's what the GFS modelled on the day

 

 

[phil nw.]

My apologies, however CAPE values in the 2000s+ are unlikely to materialise, especially in the areas predicted. That is not far from being "off the charts"; conditions that would spawn a severe thunderstorm outbreak and possibly strong tornadic activity. Having just been on the other side of the world (and "fortunate" enough to have had a tornado warning) in conditions are far more likely, its still extremely hard to pin down severity until about 24-48 hours before and even then there are downgrades.

 

That said, values around half that would provide quite a lively light show anyway.

I have removed you first post on this as it was a one liner without any explanation along with some other responses.

We do look for some substance supporting members views in this thread.

This is better Dan-thanks.  

[Milhouse]

Encouraging to see the hot spell being extended to Friday by the GFS. 30c looking ever more likely.