Model Discussion - 27th July

[bluearmy]

The morning issue from ECMWF and GFS on the 500mb anomaly charts continues with the theme of the trough(upper) edging a touch west as +ve areas are shown in an arc from SW-S-SE-NE. This has the effect of backing the 500mb flow to south of west and for heights to rise. The NOAA output last night, although hard to see it clearly as NW Europe/Scandinavia is right on the edge of their chart, appeared to show a rather similar idea.

IF this turns out right then from 9-10 days from now most of the country, starting in the SW, should see an improving picture in terms of warmth and a more settled spell. How long, if it begins, is not possible to say.

The main issue is that if these type of charts show a consistent signal then its usually fairly accurate for the upper air pattern in the time scale involved.

NAEFS seems to have lost its enthusiasm for anything settled in the second week. was rather hoping this was a 'dodgy' run but having read the meto 15 and updated 30 dayer, i'm not so sure that this wont be the new trend. the wording of the 30 dayer makes very poor reading for the se.

[Summer Sun]

Turning very unsettled in FI;

http://www.wetterzentrale.de/pics/Rtavn2641.png

http://www.wetterzentrale.de/pics/Rtavn2881.png

This pattern continues right through to the end of FI;

http://www.wetterzentrale.de/pics/Rtavn3841.png

[thestixx]

Well, It's not often I've been excited by a chart but this has it all for me, Euro high and biscay low..... Please Please Please verify....Oh, and 9 days out with heights still over Greenland!

http://www.wetterzentrale.de/pics/Rtavn2161.html

[bluearmy]

One suspects that the ECM 12z op will be a warm outler !

[Geordiesnow]

More than likely Bluearmy! Quite a hot if rather wet at times output the ECM showing albeit any rainfall could very well be of the thundery type.

GFS and UKMO does not back this up and unless the latter backs it up then its a bit hard to believe the ECM output of low pressure to the SW and high pressure to the East of us dragging hot air from the med. Especially considering the ECM has done this before and the UKMO barely predicted such an outlook so caution is needed although if people think the ECM is full of hot sunshine and blue skies then they are very much mistaken but it will feel very humid.

The GFS and UKMO show a fresher but probably a sunnier outlook although the risk of showers can't be ruled out, all in all an improvment in the outlook and perhaps something of interest for thundery weather fans.

[The PIT]

12 oz gfs very much like 00 oz ecm. |

Now they're very much unalike. Only common theme on the plus side of average and their should be some rain around even in the rain shy Sheffield region.

[Gibby]

Good evening.

GFS this evening shows Low pressure up to the NW with a slackening Westerly flow over the UK through the weekend. Apart from some rain tonight and at first tomorrow the south will be dry and bright for much of the time. With an unsettled blip looking possible on Tuesday into Wednesday in association with a small low pressure moving NE the weather then settles down in the south as high pressure develops near Southern Britain by the weekend with increasingly warm and sunny conditions. Further North though unsettled weather would probably remain as Low pressure passes east well to the North. In FI tonight things remain very changeable with a notable unsettled few days developing in the second week sandwiched by another brief settled spell before wind and rain returns by the runs end.

UKMO tonight shows a quietish spell of weather for the next 5 to 6 days. There will be some rain at times in the North and a few showers (perhaps thundery) further south from time to time later too but for much of the time the weather would remain set fair with sunny spells and temperatures slowly lifting later.

ECM tonight shows 3-4 days of quiet weather with sunny spells developing and just scattered showers in the North and West particularly. Early next week sees things warm up steadily with humidities rising quickly. From midweek onwards a strong chance of a very thundery spell develops as warm air plumes up from the South mixing with cool unstable air aloft. By the end of the week and through the weekend some very thundery weather is likely as Atlantic air progresses into the UK mixing with high surface temperatures.

Things look very changeable from the models tonight though the next 4 to 5 days overall don't look too bad and certainly an improvement on recent days for the north. GFS in FI shows changeable conditions with almost Autumn like wet conditions mixed with very reasonable days periodically. ECM offers the real chance of a major thundery spell next week with some real pyrotechnics should it verify. It is of course the forerunner of a return to cooler atlantic based weather in about 10 days time.

[johnholmes]

hi ba

Yes the overall form horse, still waiting for NOAA this evening to confirm it, would be a rather warm, muggy S-SW flow using the 10 day outlooks, say from about 7 days on from now, maybe for 4 or 5 days. Obviously any sunshine for the SE half of the UK would mean temperatures well above normal, very warm+ perhaps. A return to a more unsettled westerly type would then appear the most likely by the end of the month?

Thanks again Gibby for the usual well presented summary of the models and their likely outcome.

For newcomers to the site I recommend it as daily reading, and if Gibby keeps it going, a definite must once we get to the frantic days of late autumn into winter!

Edited August 12, 2011 by johnholmes

[bluearmy]

hi ba

Yes the overall form horse, still waiting for NOAA this evening to confirm it, would be a rather warm, muggy S-SW flow using the 10 day outlooks, say from about 7 days on from now, maybe for 4 or 5 days. Obviously any sunshine for the SE half of the UK would mean temperatures well above normal, very warm+ perhaps. A return to a more unsettled westerly type would then appear the most likely by the end of the month?

Thanks again Gibby for the usual well presented summary of the models and their likely outcome.

For newcomers to the site I recommend it as daily reading, and if Gibby keeps it going, a definite must once we get to the frantic days of late autumn into winter!

noaa charts dont look too bad john. managing to hold the upper trough out west. lets hope that naefs has less enthusiasm for the fi shallow trough on its 12z run.

incidentally, whilst the ecm op 12z run was, as expected, a warm outlier in holland, the control run was right alongside the op ................................

Edited August 12, 2011 by bluearmy

[skyblusam]

I dont rearly understand the models so when i pop into this thread i allways look for gibbys excellent summery of the models. I find these a massive help for people like me thanks again gibby.

[J10]

Quite often this summer, the ECM at around T+144 has highlighted low pressure over the UK which has tended to be not far from the mark . Hopefully this is the case for next weekend, it would be nice to have some heat and some would also like the thunderstorms.

Hopefully tomorrows charts won't end these hopes.

[Backtrack]

Quite often this summer, the ECM at around T+144 has highlighted low pressure over the UK which has tended to be not far from the mark . Hopefully this is the case for next weekend, it would be nice to have some heat and some would also like the thunderstorms.

Hopefully tomorrows charts won't end these hopes.

Surely you mean high pressure Jack?

The ECM is a cracking run. I too hope it verifies!

[ZONE 51]

Hi, here is an animation of the GFS - 18z output, the run is from friday 2100hrs - 150hrs.

you may need to run the loop once to get a better performance on second, the first and last frames stops so you know where the start and end is!

if they are liked then il put them on more often and some model chat with it! if theres anything i can do to improve the animations let me know! for example-faster or slower.

-GFS 18z animation up to 150hrs.

Edited August 13, 2011 by ElectricSnowStorm

[Bluebreezer54]

I for one appreciate your inputs Electric Snow Storm. Not model related I know but there are some quite hefty showers through the South East and London at the moment.

[ZONE 51]

I for one appreciate your inputs Electric Snow Storm. Not model related I know but there are some quite hefty showers through the South East and London at the moment.

thanks. Edited August 13, 2011 by ElectricSnowStorm

[mushymanrob]

hmmm.... the ecm suggests the hottest most widespread spell of the summer between next thursday and the following monday with the 15c upper across most of england... a hot, humid, greenhouse under bright/milky skies with massive thunderstorm potential. the gfs 00z though has non of it, and whilst isnt bad, especially for the south, it suggests no importing of continental heat but a ridge extending from the azh bringing warm atlantic weather...

id like the ecm to be nearer the mark, but tbh i expect the gfs to be closest.

[casparjack]

hmmm.... the ecm suggests the hottest most widespread spell of the summer between next thursday and the following monday with the 15c upper across most of england... a hot, humid, greenhouse under bright/milky skies with massive thunderstorm potential. the gfs 00z though has non of it, and whilst isnt bad, especially for the south, it suggests no importing of continental heat but a ridge extending from the azh bringing warm atlantic weather...

id like the ecm to be nearer the mark, but tbh i expect the gfs to be closest.

Morning Mushy,

Not wishing to be pedantic, but I can't see what you're describing 15c uppers wise across any of England, let alone most of it?; I've posted the charts I'm looking at to illustrate my confusion?

Don't get me wrong, I'd love to see that, but I can't...

[bluearmy]

Morning Mushy,

Not wishing to be pedantic, but I can't see what you're describing 15c uppers wise across any of England, let alone most of it?; I've posted the charts I'm looking at to illustrate my confusion?

Don't get me wrong, I'd love to see that, but I can't...

I think rob must have had yesterday's 12z run in his cache.

[Gibby]

Good morning. Here's a roundup of the big three this morning as I see them.

GFS shows a westerly flow from today until Monday with some bright spells and scattered showers mostly for the North and West while the South and East stay largely dry and bright. On Tuesday a trough moves east bringing rain for all before drier and warmer conditions return for the second half of the week as the Azores high ridges NE over Britain. By the weekend this slips south as Low pressure encroaches further south from the NW with a SW low and muggy conditions next weekend with some rain in the NW. In FI a trough crosses east bringing the risk of thundery rain before fresher srier conditions develop as pressure rises once more. We then develop a NW/SE split as the ridge holds on in the South while the North and West become windier and cloudier again with some rain.

UKMO shows a quiet two or three days with some bright intervals and scattered showers, mostly in the North and West in a light Westerly flow from today until Monday. On Tuesday a trough moves slowly NE bringing rain for all some of which could be heavy. This is further complicated by thundery air tracking North over France meaning the clearance of this from the SE is slowed with Wednesday and Thursday here seeing the chance of heavy thundery rain for a while while the North and West become clearer and fresher. the working week then ends on A Northerly flow around the Low in the North Sea with cooler fresher conditions for all by then with the chance of a few showers.

The Fax Charts follows the UKMO raw output this morning with the chance of thundery rain by Wednesday.

ECM is very different to last night in as much as the pattern up to Tuesday remains the same but it makes much less of the thundery risk midweek, instead restricting it to the SE while the rest of the country remains in cooler, fresher air with the rain of Tuesday having introduced these conditions. From Thursday and on through the weekend high pressure nudges across from the West with plenty of dry, warm weather developing in the south while the North and WEst see wind and rain encroaching later as the high pressure moves slowly off east and Low pressure to the NW becomes more influential again for the UK.

Things look very mixed over the next week or two with the chance of all aspects of Summer weather. There will be rain for many on Tuesday (shown by all models), a thunder risk for the South East Wednesday and Thursday (UKMO and ECM) and warm conditions at various times from GFS and ECM chiefly in the South. The details from all models will change as weak pressure systems battle for supremacy so expect further changes from run to run.

[shedhead]

Rather back down to earth with a bump this morning, as yet again a projected very warm/hot spell gets squeezed out as we approach the reliable timeframe. Given this Summer's history to date I'm surprised anyone got seduced by the outputs across the last few days; true there are signs of an overall improvement in the 500mb hemispheric pattern, but nothing that was likely to support a swing to 30c+ temps and wall to wall sunshine inside a week. As ever, the book itself is far more insightful than individual chapters within it.

Edited August 13, 2011 by shedhead

[ANYWEATHER]

A quick one from me as I need to go out, but looking across the models I see nothing different from the weeks of changable/unsettled weather to come in the nearer future. Models do seem intent on keeping the unsettled theme going, perhaps a brief warm up is on the cards but certainly nothing sustained...

[snowingman]

..yucky all the way !!!..... perhaps slightly drier than recent runs.... no settle spell at all (unless you live in Spain!)

[J10]

Surely you mean high pressure Jack?

The ECM is a cracking run. I too hope it verifies!

No I mean low pressure, many times ECM has pinpointed the next area of low pressure at T+144, and then all others models fall into line, and also the low pressure tends to deliver.

Unfortunately ECM has drifted away from that scenario of yesterdays 12Hz run, for now at least,

[nodrog]

Going into the late next week it seems a bit unsettled for the far north and west...

Possible gales? BECO think so... BECO Might this be a sign of the Atlantic opening up this first half of winter? It does seem quite energetic but most push towards Iceland as we have a lump of High pressure bouncing around down south... so the GFS says. Im I wrong?

[Gibby]

Good evening. My home is at Brean on the Bristol Channel Coast for a week so any Current Conditions I quote will be from there until next Saturday. My webcam image of course will remain from Radstock 30mls east.

GFS tonight shows the next two days with a weak westerly flow with pressure Low to the NW. There will be some sunny intervals but a few showers too, chiefly in the North and West whereas the south and east remain mostly dry and become brighter and warmer than today. On Tuesday a trough crosses east over the UK with rain for many at some stage. Then on Wednesday and Thursday pressure rises from the SW with dry weather predominating with sunny spells and increasingly warm conditions. Through the weekend pressure falls from the NW with SW winds and rain bearing fronts crossing the NW. However, dry weather hangs on in the south and east until the end of the weekend when a trough moves into what will be very warm air by then delivering thundery rain as it moves east across the UK. Thereafter, through the majority of FI winds blow from a westerly quadrant with a north/south split developing with any rain restricted to the North while the south stay dry with bright periods though often a cooling breeze. High pressure then dominates the whole UK for a while at the runs end with warmer air returning with sunnier skies too.

UKMO tonight shows a fairly quiet run of weather from now with pressure generally slack but set fair. However, as always there are exceptions and on Tuesday a trough crosses the UK bringing rain for most before pressure recovers behind it and a promising ridge of high pressure develops from the SW by the end of the run though the far SE could be affected by some thundery rain on the slow clearance from the Tuesday trough on Wednesday.

ECM is out on its own somewhat tonight with it showing the weather as remaining far more changeable than the other two. From now until Tuesday the pattern seems very much set with a dry couple of days apart from some showers in the NW and rain from the aforementioned trough on Tuesday. Its from then that the models diverge with ECM showing much more volatility in the atmosphere over and around the UK late next week. The result of which is the risk of thundery rain or showers almost anywhere up to and including Friday with the emphasis of these more towards the east. Over next weekend pressure rises from the south with a dry day or two before the run ends with a return to the all too familiar Atlantic winds with Low pressure to the North pushing occasional rain bearing troughs east over the UK.

In summary tonight the next week is divided into two camps. i.e GFS and UKMO in one corner and ECM in the other. Things up to and including Tuesday look straightforward enough with the period from midweek on up for debate. It does though look though as a warm up will occur in stagnant air later next week before Atlantic winds look like returning in a week or so time. The chance of widespread thundery weather from ECM last night though does seem to have receded today though it wouldn't take much shift in the synoptics around midweek to shift it back on again in future runs.