Model Output Discussion 00z 19/07/13

[Frosty.]

The latest fax charts show the next spell of hot and humid stormy conditions developing behind a warm front pushing up across the uk later in the week, by T+120 hours it shows the hot continental air spreading north with sunshine and thunderstorms later in the week.

[chionomaniac]

shedhead, on 28 Jul 2013 - 06:57, said:

Indeed HD...the reality of the overall situation looking forward is now starting to dawn I think.

UKMO looks a little disappointing regarding midweek plume potential, at least away from the E.

GFS offers the prospect of somewhat wider warmth and localised heat for England and Wales on Thu/Fri, but unfortunately much of Scotland and N Ireland largely miss out.

Looking farther ahead there is little if any sign of widespread cool, wet conditions, but a NW/SE split does look set to develop, with most places seeing pretty bog standard Aug weather....which to be fair should still be very pleasant and useable for much of the time.

The longer range 500mb anom charts certainly want to rev things up a bit in the N Atlantic....

I think that the current pattern is very interesting because there are a number of possibilities on offer due to the nature and difficulties of forecasting weak troughing around the UK. There still seems to be a trend of weak surface based low pressures forming around the Bay of Biscay and travelling NNEwards. The exact positioning and trajectories of these determines whether the days felt at the surface will be average or indeed like yesterday hot and humid followed by a downpour.

The anomaly chart, Shed, that you have posted above is one snapshot of one day at the end of FI on the latest GFS run, and is not an indication of the Atlantic revving up. A better indication would an average anomaly from days 10-16 from all the ensembles of all models preferably - and only when that shows a significant anomaly can confidence be gained.

Edited July 28, 2013 by chionomaniac

[shedhead]

I think that the current pattern is very interesting because there are a number of possibilities on off due to the nature and difficulties of forecasting weak troughing around the UK. There still seems to be a trend of weak surface based low pressures forming around the Bay of Biscay and travelling NNEwards. The exact positioning and trajectories of these determines whether the days felt at the surface will be  average or indeed like yesterday hot and humid followed by a downpour. 

 

The anomaly chart, Shed, that you have posted above is one snapshot of one day at the end of FI on the latest GFS run, and is not an indication of the Atlantic revving up. A better indication would an average anomaly from days 10-16 from all the ensembles of all models preferably - and only when that shows a significant anomaly can confidence be gained.

I know that Chio, it was posted tongue in cheek, much as the same T+384hr showing a solid high pressure anom over the UK was posted by tempestas recently.

 

That said, if you run the sequence from T+274hr you can see the pattern evolving for a much more active N Atlantic. Whether it will get far enough south to affect us though remains to be seen, but the latest MO outputs seem to suggest it will.

 

UK Outlook for Thursday 1 Aug 2013 to Saturday 10 Aug 2013: A rather unsettled start to August, with a risk of rain or showers in many areas, perhaps thundery in nature towards the southeast UK

Outlook for Sunday 11 Aug 2013 to Sunday 25 Aug 2013:  The latest indications are that the changeable conditions expected during  the start of August should persist during the middle part of the month

Edited July 28, 2013 by shedhead

[mushymanrob]

Who has written off Aug JH?  I haven't seen one post in here to that effect, but have you seen it said elsewhere?

 

ive not written august off as such, but have suggested that i think theres a fair chance that it wont settle down giving us another long dry sunny warm spell, as the synoptic pattern appears to be moving away from the chances of one evolving. thats just a thought, and as john says has no science behind it. ive been wrong many times before, i hope i am on this!

 

.... and maybe there are hints in fi that my negetive thoughs are misplaced.

 

the sequence sees the azh ridging ne wards. IF this chart varified though it would be rather cool and autumnal, especially in the early mornings. hopefully this ridge would build, displace from the azores, and deliver us another lengthy sunny, warm, dry spell through the heart of august.

 

but if it doesnt evolve like this or something similar in this timeframe (or is apparent that it might, by the end of the first week in august), then the chances of august delivering a decent spell of dry sunny and warm/hot weather must be severely diminished ... there would be only 3 weeks left of 'summer'.

Edited July 28, 2013 by mushymanrob

[shedhead]

ive not written august off as such, but have suggested that i think theres a fair chance that it wont settle down giving us another long dry sunny warm spell, as the synoptic pattern appears to be moving away from the chances of one evolving. thats just a thought, and as john says has no science behind it. ive been wrong many times before, i hope i am on this!

 

.... and maybe there are hints in fi that my negetive thoughs are misplaced

 

the sequence sees the azh ridging ne wards. IF this chart varified though it would be rather cool and autumnal, especially in the early mornings. hopefully this ridge would build, displace from the azores, and deliver us another lengthy sunny, warm, dry spell through the heart of august.

 

but if it doesnt evolve like this or something similar in this timeframe (or is apparent that it might, by the end of the first week in august), then the chances of august delivering a decent spell of dry sunny and warm/hot weather must be severely diminished ... there would be only 3 weeks left of 'summer'.

 

Feel much the same here Mushy.  Next month looks similar to last August imo, pretty decent in the E and especially the SE, but decidedly ordinary by and large. That said, still some very pleasant and usable weather for all of us at times, but like you I just can't see a return to fine, settled conditions, at least not based on the latest outputs. 

Edited July 28, 2013 by shedhead

[Frosty.]

More hot and sticky, thundery weather with hazy sunshine on the way for the second half of the week ahead for the southern half of the uk as the 564 dam line pushes up from the south again, shown here on the latest fax chart and the Ecm 00z with the glorious deep oranges, purples and reds making a comeback, only the far north ends up green with envy on this run, along with the heat comes more storms, either homegrown or from the near continent, a thundery breakdown seems assured at the end of the week, especially further southeast.

 

Early in the week it looks a bit cooler and fresher relative to the recent heat and also changeable with heavy rain at times for most of the uk but then that next surge of heat pushing north just after midweek behind a warm front, you could call it a hot front as the continental heat and humidity will follow in behind it, only the far north and west of the uk missing the heat and having pulses of heavy rain at times throughout the next 7 days.

[draztik]

Feel much the same here Mushy. Next month looks similar to last August imo, pretty decent in the E and especially the SE, but decidedly ordinary by and large. That said, still some very pleasant and usable weather for all of us at times, but like you I just can't see a return to fine, settled conditions, at least not based on the latest outputs.

yes, i was actually having a look at last August, and certainly for the London area it was a generally very pleasant month in all, particularly in terms of recorded temperatures..

http://m.accuweather.com/en/gb/london/ec2v-7/month/328328?monyr=8/01/2012

If this August proceeded the same way, I suspect most would be pleased. But as you rightly pointed out, there were regional differences.. others saw a mixed bag!

Edited July 28, 2013 by draztik

[mushymanrob]

Feel much the same here Mushy.  Next month looks similar to last August imo, pretty decent in the E and especially the SE, but decidedly ordinary by and large. That said, still some very pleasant and usable weather for all of us at times, but like you I just can't see a return to fine, settled conditions, at least not based on the latest outputs. 

 

oh indeed, im not saying that just because another lengthy dry sunny warm spell is in doubt, itll be rubbish! far from it, i should have made that clearer, im not expecting a 'bad' august... to my unscientific eye its looking average.. which isnt bad especially as you say for eastern and southeastern areas.

[shedhead]

The lack of posts in here this morning pretty much says it all about the longer term prospects imo, but there is still plenty of interesting weather to come later this week, with the 06 GFS again supporting a significant plume for England and Wales in particular.

 

Due to the lack of any decent heat build day time max records still look set to remain well intact, but overnight Thurs looks particularly warm and humid, so we may well see mins in the 18-20c range for several major conurbations and perhaps 21c+ in Central London.  Friday should see 30c across a fairly large part of Eastern England too, with a localised 34c not out of the question.

 

So thinking back to last Summer now, this place would have been absolutely buzzing given these prospects, so quite what most folk are expecting i just don't know....this is the UK after all.

Edited July 28, 2013 by shedhead

[Captain Shortwave]

The lack of posts in here this morning pretty much says it all about the longer term prospects imo, but there is still plenty of interesting weather to come later this week, with the 06 GFS again supporting a significant plume for England and Wales in particular.

 

Due to the lack of any decent heat build day time max records still look set to remain well intact, but overnight Thurs looks particularly warm and humid, so we may well see mins in the 18-20c range for several major conurbations and perhaps 21c+ in Central London.  Friday should see 30c across a fairly large part of Eastern England too, with a localised 34c not out of the question.

 

So thinking back to last Summer now, this place would have been absolutely buzzing given these prospects, so quite what most folk are expecting i just don't know....this is the UK after all.

Partly that, partly it's a Sunday and partly exhaustion from yesterdays storm watch.

GFS still teasing the potential for the hottest day of the year on friday. In fact Friday looks like a great day away from extreme western parts of England and Wales, Western Scotland and Northern Ireland.

Both GFS and ECM are developing another trough behind the one which will pass through Friday and into the weekend. This one was the deep little low on the T168 ECM chart today. That is worth watching as it also takes a rather southerly route and yet again could push another surge of heat northwards.

ECM

 

Previous GFS run

 

Also is it just me or does nearly every 06z GFS run try and build heights towards Greenland. I've noticed that a lot over recent weeks?

Edited July 28, 2013 by Captain shortwave

[shedhead]

Partly that, partly it's a Sunday and partly exhaustion from yesterdays storm watch.

GFS still teasing the potential for the hottest day of the year on friday. In fact Friday looks like a great day away from extreme western parts of England and Wales, Western Scotland and Northern Ireland.

Both GFS and ECM are developing another trough behind the one which will pass through Friday and into the weekend. This one was the deep little low on the T168 ECM chart today. That is worth watching as it also takes a rather southerly route and yet again could push another surge of heat northwards.

ECM

 

Previous GFS run

 

Also is it just me or does nearly every 06z GFS run try and build heights towards Greenland. I've noticed that a lot over recent weeks?

Make no mistake CS, if all the models showed the LP stalling and a lenghty heatwave starting Thurs this place would be rammed imo, the fact it's Sunday and yesterdays storm (that wasn't in many places) fatigue wouldn't come into it.

 

I too haved noticed the height rises towards Greeny on the 06, but I have also noticed that the 06s' have produced some of the warmest plume forecasts, so will be interesting now to see where the 12's go from all 3.

 

Longer term GFS pretty much sticks with it's increasingly unsettled pattern, with charts like this being indicative of the 500mb anom chart I posted earlier.

 

Edited July 28, 2013 by shedhead

[Summer Sun]

The 00z ensemble for London shows the real possibility of some hot weather later this week with uppers just under +20 longer term uppers stay around average for a long time yet and rainfall eases back again after this wet spell

 

 

Further north the uppers get to around +15 again longer term the uppers stick around average

 

 

Dublin is just under the +15 mark again longer term the uppers stick around average

 

[Captain Shortwave]

Make no mistake CS, if all the models showed the LP stalling and a lenghty heatwave starting Thurs this place would be rammed imo, the fact it's Sunday and yesterdays storm (that wasn't in many places) fatigue wouldn't come into it.

Well fatigue as in extensive radar watching followed by extensive ranting, I know I was one of then 

The point about that low is simple, the models are just beginning to pick up on it, hence it needs watching to see how it is resolved, whether it either crashes through the UK at the start of the following week, digs south towards Biscay throwing up another brief plume or is simply removed on future runs.

For starts the ensemble means so far show no evidence really of its existence.

 

Edit - I'm quite surprised by the week ahead forecast, going for a cool down Friday despite GFS/ECM and ensembles backing Friday to be the warmest day this week.

Edited July 28, 2013 by Captain shortwave

[joggs]

Dont post that much on this thread but love reading it and just want to say thanks to everybody contributing.Keep up the good work all.Sorry mods.

[Summer Sun]

BBC weather for the week ahead shows the next hot spell very nicely

 

31c for London on Thursday with lots of sunshine and 25c as far north as Newcastle

 

25c in the parts of the south and SE corner on Friday with rain possible so thunderstorms can't be ruled out here mid to low 20's then as far north as Aberdeen with more sunshine away from parts of the south and SE corner

 

So after a brief cooler spell the heat is set to make a welcome return this week

Edited July 28, 2013 by Summer Sun

[Frosty.]

The Gfs 06z has upgraded the hot spell later in the week with a lovely hot plume pushing north across the uk with scorching sunshine and scattered thunderstorms, temperatures into the mid to high 80's to low to mid 90's on thursday and especially next friday, although the uppers cool off by next weekend, the surface conditions still looks rather warm with temperatures into the mid 20's celsius but progressively cooler further west and north. The week ahead starts unsettled with sunny spells and a lot of heavy showers tomorrow and to a lesser extent on tuesday, the most unsettled weather then becoming confined to the far west and north of the uk for the second half of the week with pulses of heavy rain running north and then east across those areas but further south it's an active warm front pushing north with heavy rain along it which marks the boundary between average temperatures and the hot & sultry continental air pumping up from the south, within the hot zone there will be a lot of sunshine and a scattering of storms with some storms also drifting up from france towards the southeast, into next weekend the more unsettled conditions across the west and north look like pushing southeastwards to remaining areas but remaining on the warm side of average. I notice the bbc forecasts are again typically underplaying the heat potential and only showing 25 celsius for next friday, just as they did at a similar stage before the recent mega hot spell, it will be interesting to see how this plays out, upgrades to the heat nearer the time me thinks, I would expect to see those bbc maps to start showing 28c, then 30 and then 32c on the coming days for late in the week based on the northward progress of the 564 dam line

Edited July 28, 2013 by Frosty039

[DTHFCJ]

BBC weather for the week ahead shows the next hot spell very nicely

 

31c for London on Thursday with lots of sunshine and 25c as far north as Newcastle

 

25c in the parts of the south and SE corner on Friday with rain possible so thunderstorms can't be ruled out here mid to low 20's then as far north as Aberdeen with more sunshine away from parts of the south and SE corner

 

So after a brief cooler spell the heat is set to make a welcome return this week

Summer sun have you got a link to that please?

[Cheshire Freeze]

BBC weather for the week ahead shows the next hot spell very nicely31c for London on Thursday with lots of sunshine and 25c as far north as Newcastle25c in the parts of the south and SE corner on Friday with rain possible so thunderstorms can't be ruled out here mid to low 20's then as far north as Aberdeen with more sunshine away from parts of the south and SE cornerSo after a brief cooler spell the heat is set to make a welcome return this week

When was that on?? Is it not on during Countryfile anymore? Was going to watch it.

[Summer Sun]

Summer sun have you got a link to that please?

 

Not yet it will be in the media thread asap

When was that on?? Is it not on during Countryfile anymore? Was going to watch it.

 

Was on just after the lunchtime news at 12:08 ish

Edited July 28, 2013 by Summer Sun

[DTHFCJ]

When was that on?? Is it not on during Countryfile anymore? Was going to watch it.

it used to be,its defo on this evening though ....they sometimes put it on the bbc website though....

[Cheshire Freeze]

Not yet it will be in the media thread asapWas on just after the lunchtime news at 12:08 ish

Wish they'd stop messing things about! It has always been on about 48 minutes into Countryfile!

[Summer Sun]

Wish they'd stop messing things about! It has always been on about 48 minutes into Countryfile!

 

No thats on the evening one the lunchtime week ahead forecast keeps moving depending on whats on

[TEITS]

The lack of posts in here this morning pretty much says it all about the longer term prospects imo, but there is still plenty of interesting weather to come later this week, with the 06 GFS again supporting a significant plume for England and Wales in particular.

 

Due to the lack of any decent heat build day time max records still look set to remain well intact, but overnight Thurs looks particularly warm and humid, so we may well see mins in the 18-20c range for several major conurbations and perhaps 21c+ in Central London.  Friday should see 30c across a fairly large part of Eastern England too, with a localised 34c not out of the question.

 

So thinking back to last Summer now, this place would have been absolutely buzzing given these prospects, so quite what most folk are expecting i just don't know....this is the UK after all.

The lack of posts is probably more due to the fact that short term prospects are very exciting i.e heat, more storm potential that many aren't bothered by the long term prospects.

 

Besides I have been reading some archive threads and many of your posts are on the glum side and yet look at what a fantastic spell of weather we have already had. We all know the long term prospects are subject to change. As an example next weeks brief heatwave wasn't suggested by the models 7-10 days ago, far from it they were suggesting cool, unsettled W/NW,lys.

 

I have already commented that the models for much of this month have been far too progressive in introducing cool W,lys with low pressure passing E across the UK. The reality is we have remained warm, hot at times with thundery outbreaks.

 

Lastly I commented a few days ago about how ensembles generally follow operationals if they are consistent and below is a good example.

 

http://cdn.nwstatic.co.uk/ensimages/ens.20130728/00/t850Cambridgeshire.png

 

Few ensembles suggested a hot plume and now look we have a mean of 15C!

 

 

18C mean on the 06Z ensembles.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=6&ville=Londres&runpara=0

Edited July 28, 2013 by THE EYE IN THE SKY

[Frosty.]

The lack of posts is probably more due to the fact that short term prospects are very exciting i.e heat, more storm potential that many aren't bothered by the long term prospects.

 

Besides I have been reading some archive threads and many of your posts are on the glum side and yet look at what a fantastic spell of weather we have already had. We all know the long term prospects are subject to change. As an example next weeks brief heatwave wasn't suggested by the models 7-10 days ago, far from it they were suggesting cool, unsettled W/NW,lys.

 

I have already commented that the models for much of this month have been far too progressive in introducing cool W,lys with low pressure passing E across the UK. The reality is we have remained warm, hot at times with thundery outbreaks.

 

Lastly I commented a few days ago about how ensembles generally follow operationals if they are consistent and below is a good example.

 

http://cdn.nwstatic.co.uk/ensimages/ens.20130728/00/t850Cambridgeshire.png

 

Few ensembles suggested a hot plume and now look we have a mean of 15C!

 

 

18C mean on the 06Z ensembles.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=6&ville=Londres&runpara=0

Well said mate, top post.

[draztik]

So after a brief cooler spell the heat is set to make a welcome return this week

a brief return, would have been a more accurate way of describing it. Please, don't get ahead of yourself. The models show this to be rather brief. If we listened to you and frosty, we'd be forgiven for thinking we were about to head into round 2 of the heatwave! No! Edited July 28, 2013 by draztik