Model Output Discussion

[ANYWEATHER]

Evening folks. Quick summery from me, is that the unsettled weather is here to stay for now, rather cool especially in the east in the next few days and then warming up somewhat,towards the weekend as warmer ,humid air moves in from the southwest for a time, but the weekend could well turn out to be wet/very wet in some areas.....UUMMMGGHH! :lol: :lol:

[The PIT]

Unsettled run through from the GFS while the ECM maybe more positive in deep FI. No sign of a return to summer for a while anyway.

[Snowyowl9]

Yes looks like we`ll have to wait quite a while now for either thunder or a settled spell,2nd half of July would be a good chance I would think,before then just unsettled to wet atlantic SW-lys to put up with from the weekend.

[BLAST FROM THE PAST]

Is there such a thing as "faux heat" then?

Someone read my post then

BFTP

[Eugene]

I am astounded by most comments in model chat, the runs are poor with unsettled westerlies dominating, when have they ever been good, only in July it seems :lol:

Even UKMO 12Z was poor with more southerly tracking Lows on their way towards us, ensembles are poor too and other runs including ECM 12Z.

[mushymanrob]

i dont think this mornings runs are that bad, ok theres alot of uncertainty but there are hints that things could warm up and it wouldnt take a huge synoptic shift to return us to something much warmer/sunnier. all in all, a set of pretty normal july weather conditions on offer.

[TEITS]

I am astounded by most comments in model chat, the runs are poor with unsettled westerlies dominating, when have they ever been good, only in July it seems

Even UKMO 12Z was poor with more southerly tracking Lows on their way towards us, ensembles are poor too and other runs including ECM 12Z.

Your not looking at the wider picture Eugene and taking the model output as gospel. If we assumed the models were always correct beyond +96 there would be little to discuss.

What some have been discussing is whether the LP will make its way across the UK bringing a continuation of W,lys. There has been some hints that this LP will stall in the Atlantic and with rising pressure to our E we could see a hot plume arrive from the S. Now at the moment the models seem to have backed away from this and if you read my post from yesterday I did suggest the heat would remain to the E. However im still not ruling out these hot S,lys from mid July onwards.

You never take the model output as gospel in winter so why should you in summer?

[tcc]

I'll take the thin green line in FI please Bob...

http://91.121.93.17/pics/MT8_London_ens.png

I wonder how hot that would be!

[Thundery wintry showers]

850hPa temps of 25C would probably bring maxima of 40C in south-east England! Values of 22-24C gave highs of 40C over much of France during August 2003, although on that occasion the ground was much drier which helps heat accumulations.

As Mushymanrob suggested- a pretty average outlook and IMHO that build of high pressure to the east could play its part later in the month. Note that "average" does not imply a repeat of the last two summers as although temperatures were close to average in both cases, rainfall was well above and, for most, sunshine well below.

[Guest North Sea Snow Convection]

Looks like one of the repeating themes of the early part of the summer to my humble little eye. Can't remember exactly to the date when, but sometime in June, there was a pattern of a slow moving trough which approached the UK but came far enough east to keep things coolish and unsettled for a while and didn't stay far enough west for hot southerlies - which went into mainland europe - and the majority of computer models suggest something similar once again atm.

In the end as we know, the recent very warm spell came about through pressure building from the south west into Scandinanvia and then a block from there providing those sunny easterlies which eventually led to the hot weather pattern of the end of June to the start of this month.

ECM hints at another ridge building from the south west in la la land this am - and it could just be that following a rather unsettled spell with more sunshine and showers with ukky south westerlies next week, the next fine summery spell evolves in the same way. Cue end of May, end of June...last week of July perhaps??

Edited July 8, 2009 by North Sea Snow Convection

[edveasey]

Next week is looking interesting, there is a degree of uncertainty from Monday onwards that could bring us an excellent week of summer weather. On the other hand as the heat over central Europe builds next week and with the proximity of the low to the UK it could mean fireworks right over the top of us Wednesday-Friday next week (to me it looks like a similar general situation to the summer a couple of years ago when the west country suffered severe flooding)

[Methuselah]

If that low pressure stays to the west next week could be quite warm, especially at night; I wouldn't entirely rule-out an odd localised 26C somewhere in the SE. Heavy showers and thunderstorms? Quite possibly IMO. But don't count on it!

Just to point out that for weather to be 'good', I don't need 15 consecutive days' wall-to-wall sunshine @ 33C+...

[mushymanrob]

Just to point out that for weather to be 'good', I don't need 15 consecutive days' wall-to-wall sunshine @ 33C+...

i dont need it, but it would be nice!

the 06z hints at the stalling low just to our west early next week, but imho it currently looks too close to bring much widespread heat. personally id prefer a slow building high that lasts over us for a couple of weeks before drifting eastwards allowing hot humid southerlies.... but that aint on offer.

[William of Walworth]

I'm not optimistic for any really summery conditions any time next week, on current signals. The SE just possibly excepted. Low pressure looking just too close to our W.

Beyond next week, all still to play for though .... still altogether possible that July could go out with a nice warm or even hot spell. I'm cautiously optimistic on that.

[Derp Patrol]

Argh next week i'm going to cornwall.. just when the models show that the SE might get some decent weather.. :winky:

[PB22]

Some uncertainty over details for next week, but the underlying theme is there for northern and western areas to see the worse of the unsettled conditions, with the southeast having greatest potential for drier and warmer conditions to develop. Once again the GFS ensembles show the operational run to be one of the warmest runs towards the southeast:

http://www.wzkarten.de/pics/MT8_London_ens.png

This has been the case for several runs now, and given that the operational is run at a higher resolution than the ensemble members then I would take what it is showing quite seriously.

I feel that model output over the next few days will become increasingly favourable for warmer conditions to develop again, and in any case, there will be plenty of half decent weather around after the weekend, with even the north and west likely to see some drier and sunnier spells too.

In the meantime, the weekend is worth watching, as if the low stalls to the west, some places could see a lot of wet weather - most likely towards western areas.

[edveasey]

Hi Paul that would be my reading of the situation also

Also keep a watch out; if the continental air makes it's way upwards for the likelyhood of some very heavy rain as comes up against the atlantic LP has the potential to be very nasty.

interesting I've noticed that GFS is determined to develop low pressure over scandanavia, if this is the likely trend in the medium term then any fine weather we do experience next week will be short lived

[North-Easterly Blast]

850hPa temps of 25C would probably bring maxima of 40C in south-east England! Values of 22-24C gave highs of 40C over much of France during August 2003, although on that occasion the ground was much drier which helps heat accumulations.

As Mushymanrob suggested- a pretty average outlook and IMHO that build of high pressure to the east could play its part later in the month. Note that "average" does not imply a repeat of the last two summers as although temperatures were close to average in both cases, rainfall was well above and, for most, sunshine well below.

Many on here keep commenting about how bad the last two summers have been. I will say my point in that while summer 2008 saw rainfall above average and sunshine below - temperaturewise it STILL ended up close to average, and STILL a shade ABOVE average by 1961-90 standards. So it is a total load of tosh that summer 2008 was that bad. Summer 2007 was a wetter summer still than last year, and just marginally cooler than the 1961-90 average. It is the truth that we have not had a summer that could be described as "cool" since 1993, and before that the four summers from 1985-1988.

[Bottesford]

Many on here keep commenting about how bad the last two summers have been. I will say my point in that while summer 2008 saw rainfall above average and sunshine below - temperaturewise it STILL ended up close to average, and STILL a shade ABOVE average by 1961-90 standards. So it is a total load of tosh that summer 2008 was that bad. Summer 2007 was a wetter summer still than last year, and just marginally cooler than the 1961-90 average. It is the truth that we have not had a summer that could be described as "cool" since 1993, and before that the four summers from 1985-1988.

A bad summer isn't just about how warm it is - sunshine & rainfall are just as important if not more so to most people.

To Mr Average - the 'best' summers are (in order of preference) ones with the most sunshine, the least rainfall and the warmest temperatures.

2008 was a very dull summer even if it wasn't cool. That factors higher in most peoples minds than overall day & night temperature averages.

[Derp Patrol]

2008 only had close to average temps because of high night time temperatures. Most of the summer in the SE consisted of temps in the high teens and low twenties, below the July average of about 22C-23C. The other poor aspect of the last 2 summers was the lack of any lengthy settled spells, only a short period last year in July which bought a few days of sunny weather and very warm temperatures. The last two years also saw the 30C just broken on only a few days and other than that practically the whole time it was either raining or cloudy.

Just because the mean temperatures were close to average, it does not mean that a summer can be considered good, other factors including rainfall and sunshine should be included, who would want a summer with 22C everyday with grey cloudy skies?

[mushymanrob]

2008 only had close to average temps because of high night time temperatures. Most of the summer in the SE consisted of temps in the high teens and low twenties, below the July average of about 22C-23C. The other poor aspect of the last 2 summers was the lack of any lengthy settled spells, only a short period last year in July which bought a few days of sunny weather and very warm temperatures. The last two years also saw the 30C just broken on only a few days and other than that practically the whole time it was either raining or cloudy.

Just because the mean temperatures were close to average, it does not mean that a summer can be considered good, other factors including rainfall and sunshine should be included, who would want a summer with 22C everyday with grey cloudy skies?

exactly, the high night time maxima was resposible for the cet being 'average'. and 08 precipitation was anything but 'average' with many places experiencing flooding, something i cant recall from the 60's- 90's.

the 12z continues to tease us with a couple of warm summery days here and there as a succession of short lived ridges tempt us into 'summer mode'. hopefully one of these will build and sit closeby, all in all theres plenty to be optimistic about

[Eugene]

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

No sign of any heat or prolonged settled spell on tonights runs with LP hovering around the UK most of the time there is always the chance of rain especially in the west, i suppose the far SE has the potential for grazing plumes , all in all its looking mediocre at best.

Not even the heat rampers favourite model ECM offers much hope with atlantic lows constantly swinging our way.

[ANYWEATHER]

From the short to medium and long term, both gfs and ecm show low pressure in control . Of course medium and long term can change a fair bit, looks as though it will be wet and muggy short term especially in the SE of the uk, and it looks as though "shortwave troughs" will provide some thundery rain to all,and some warm muggy air in the south of the UK. All in All a proper "British Summer"!

[PB22]

Hi Paul that would be my reading of the situation also

Also keep a watch out; if the continental air makes it's way upwards for the likelyhood of some very heavy rain as comes up against the atlantic LP has the potential to be very nasty.

interesting I've noticed that GFS is determined to develop low pressure over scandanavia, if this is the likely trend in the medium term then any fine weather we do experience next week will be short lived

Hi Edveasey,

Yes, with the possibility of very warm air pumping northwards, there is likely to be some very heavy rain in places. I have growing confidence of increasing temperatures later next week with the potential for thundery weather as well. The UKMO T+144 chart shows one of the possibilities well:

http://www.wzkarten.de/pics/Rukm1441.html

It really wouldn't take too much of a shift for that hot continental air to affect southeast Britain in particular. However, the other models aren't quite so keen on the idea tonight although ECM at T+120 suggests very wamr conditions in the southeast:

http://www.wzkarten.de/pics/Recm1201.html

Giving way to thundery weather by T+144:

http://www.wzkarten.de/pics/Recm1441.html

Overall conditions will almost certainly be warmer next week, but other than that detail is very hard to pin down.

In the meantime, the upcoming weekend looks changeable:

http://www.wzkarten.de/pics/Rtavn961.html

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Recm961.html

But could be quite warm and humid in the south:

http://www.wzkarten.de/pics/Rtavn902.html

http://www.wzkarten.de/pics/Rtavn10217.html

I'd like to know what people constitute as a typical "British Summer". In my view, it is several days of very warm or hot temps with sunshine, followed by a thundery breakdown. Repeat the process and there's your British Summer. Quite a few people seem to thing that prolonged cool conditions is the norm for the country, though I suppose times are changing and so is the climate.

Ask 100 people and you'd probably get 100 different answers! The British climate is variable with no set weather pattern really dominating for long. Anyone who expects prolonged heat and sunshine is living in the wrong country!

[Frosty.]

The 12z models look unsettled for next week, especially the ukmo & ecm but the gfs brings a brief return to hot/humid weather later next week into the weekend for more south eastern areas but is on it's own with that idea as the ecm keeps the hot weather across mainland europe instead. It could be very wet in NW Britain next week with low pressure set up sw to ne to the nw of the uk with high pressure close to the south east.