Model Discussion - 27th July

[mushymanrob]

GFS showing a very poor first 15 days of August. Besides from a brief 1 day ridge, there's nothing to even clutch at.

I did predict this back in the CET thread about a week or so ago. I'm hopeful of an Indian summer.

eh?.... it looks average at worst, and average for early august is pretty pleasant.

Yes very nice.. 25-30C for the next 5 days and lows of 15-18C.. nothing to complain about really.

August I find is normally the best summer month, I don't know why some on here find it to be autumnal?

not all of us live in one of the warmest, sunniest part of the country, and i said that august can feel autumnal especially the second half IF we have cool weather.

this mornings gfs is very progressive with next weeks atlantic systems, whilst the ecm stalls them and prolongs a slow building ridge thats expected to build after this weeks thundery low moves into europe later in the week. as expected theres alot of cloudy skies about today, whether or not we get any heat depends upon where the breaks occur, the east being favoured. maybe an odd 30c somewhere over the next few days is possible. but like the first 2/3rds of summer theres nothing sustained.

[Paul]

Staying On Topic (ie discussing the models)

As Oon said yesterday - we're fairly relaxed across many areas of the forum but this area is one place where we know (from feedback and the amount of complaints we get) that members want an on topic discussion strictly adhered to.

There are so many other places to have general weather discussions, cet discussions and in fact discussions about pretty much every single other aspect of the weather and climate so there really is no excuse whatsoever to be using this thread for anything other than model discussion..

With this in mind we're going to have no hesitation in stopping people using this entire area to post if they continually post off topic - and for the avoidance of doubt, we'll consider on topic to mean actually discussing the models, not posting a para of unrelated material and adding the word models in there somewhere or putting a link to a chart at the bottom.

[Gibby]

GFS shows a couple more days of slack pressure gradients with some thundery rain breaking out in places, chiefly in the North and west innitially and the east on Wednesday. Later in the week cooler and fresher air crosses from the west with sunshine and showers to end the week as Low pressure over the North generates westerly winds for most. These turn Northwesterly for a while ahead of a weak ridge drying things up in a weeks time. Improvements are temporary as further Low pressure followed by ridges maintain the changeable theme going before a more concerted attempt of better weather arrives late in the run as High pressure develops from the SW.

UKMO shows a continuation of its theme of previous runs with weak Low pressure bringing a slow deterioration of weather through the week. However, a lot of dry weather is still likely with the thundery breakdown only sporadic in nature with the North and west at risk from heavy rain tonight and the SE on Wednesday. Thereafter things turn slowly fresher from the west with showers and sunny spells most likely in the west and North and temperatures returning to normal values.

ECM also shows a slow deterioration through the week though widespread rain is not shown. A slightly thundery breakdown could occur in places, maybe the North and west tonight and the east on Wednesday as a small thundery depression moves NE in the Straits of Dover with fresher and cooler conditions spread to all areas behind it as Low pressure lies close to the North and West by the end of the week. In the later stages of the run pressure falls over Scandinavia with a burst of cool NW winds for Britain ahead of a ridge and further breakaway Low pressure crossing the North late in the run delivering some more rain to many then.

The pattern remains unchanged this morning although as I have indicated in past days I don't think the weather for much of the time is going to be that bad. True, there will be showers or rain at times for all but amounts for some will end up being small while a few have rather a lot. Despite the humidity of the next few days I cannot currently see where any widespread thundery activity is coming from on this side of the channel and the fresher air that follows will hold just scattered showers and sunny spells with further hints of weak ridges at least delivering some dryish and pleasant enough conditions at times next week albeit short lived for most as pressure remains stubbornly high over Greenland.

[casparjack]

eh?.... it looks average at worst, and average for early august is pretty pleasant.

not all of us live in one of the warmest, sunniest part of the country, and i said that august can feel autumnal especially the second half IF we have cool weather.

this mornings gfs is very progressive with next weeks atlantic systems, whilst the ecm stalls them and prolongs a slow building ridge thats expected to build after this weeks thundery low moves into europe later in the week. as expected theres alot of cloudy skies about today, whether or not we get any heat depends upon where the breaks occur, the east being favoured. maybe an odd 30c somewhere over the next few days is possible. but like the first 2/3rds of summer theres nothing sustained.

I think the best way to sum up the next three/four days is frustrating, yes somewhere in the E/SE will undoubtedly reach 30c, but looking at the run of FAX charts from 0z today right through to T96 when the front currently to our West is still hanging around across the middle of the country we always have cloud in the mix, a good heat source, but too much moisture.

By T192 the ECM shows yet another attempt by the Azores high to ridge across the UK from the SW, but as already this season, the next low comes barrelling in and barges it out of the way - we are stuck with this southerly jet it seems - the clock is now ticking for summer 2011 I fear; that is if you're looking for a sustained period (five/seven days) of clear/sunny/warm weather...

[MP-R]

I think the best way to sum up the next three/four days is frustrating, yes somewhere in the E/SE will undoubtedly reach 30c, but looking at the run of FAX charts from 0z today right through to T96 when the front currently to our West is still hanging around across the middle of the country we always have cloud in the mix, a good heat source, but too much moisture.

By T192 the ECM shows yet another attempt by the Azores high to ridge across the UK from the SW, but as already this season, the next low comes barrelling in and barges it out of the way - we are stuck with this southerly jet it seems - the clock is now ticking for summer 2011 I fear; that is if you're looking for a sustained period (five/seven days) of clear/sunny/warm weather...

Sadly so.

The GFS in particular really has powered up some of the lows for later this week. Once a slack pattern with mid-low pressure around...now well and truly unsettled and probably feeling quite cool by the end of the week with uppers dipping. Then a transient ridge next Monday before the next load arrives. Again, something more settled looks like appearing out in FI but, as we know, that's way too far away to be reliable. We could really do with some hot highs being forced over us from tropical storms.

[shedhead]

Sadly so.

The GFS in particular really has powered up some of the lows for later this week. Once a slack pattern with mid-low pressure around...now well and truly unsettled and probably feeling quite cool by the end of the week with uppers dipping. Then a transient ridge next Monday before the next load arrives. Again, something more settled looks like appearing out in FI but, as we know, that's way too far away to be reliable. We could really do with some hot highs being forced over us from tropical storms.

Agree with this. GFS in particular offers little hope of any protracted fine, warm and settled weather, indeed if you live anywhere other than central and eastern England and east Wales even the next few days promise little in the way of warm sunshine. The best hope as we move further into August is either an ex TS or ex Hurricane becomes cut off in the Atlantic and pumps up some Tm air, but given the current model output this does not look like a viable option any time soon - so true Summer (at least as most like to think of it) looks set to remain as elusive as ever.

Edited August 1, 2011 by shedhead

[Summer Sun]

06Z has developed a deep area of low pressure for Saturday down as low as 990mb

http://www.wetterzentrale.de/pics/Rtavn1321.png

http://www.wetterzentrale.de/pics/Rtavn1561.png

After this moves away by Monday we are left with high pressure trying to push into the south but this get's pushed away by low pressure once again. All models are in agreement that after this humid air moves away there will be an un-settled spell of weather and potentially quite a windy spell this weekend.

[Bobby]

August for my location at least is significantly wetter than June or July as the Jetstream fires up and starts tracking further South. I guess this is what we're starting to see in the models. A first taste of Autumn...

[shedhead]

06Z has developed a deep area of low pressure for Saturday down as low as 990mb

http://www.wetterzen...s/Rtavn1321.png

http://www.wetterzen...s/Rtavn1561.png

After this moves away by Monday we are left with high pressure trying to push into the south but this get's pushed away by low pressure once again. All models are in agreement that after this humid air moves away there will be an un-settled spell of weather and potentially quite a windy spell this weekend.

Yes indeed Gavin, fair to say this chart has a distinctly autumnal look to it and would not be out of place in early November. Certainly the potential for some strong, even gale force gusts in the west IF it were to verify, especially around showers which do look set to rattle east at times.

Edited August 1, 2011 by Paul

[Paul]

I've split the thread out, so if you want to discuss the workings of the model thread you can here:

http://forum.netweather.tv/topic/70508-model-threads-discussion/

[Alex]

The Ensembles were interesting on the 06z i'm awaiting an update for the 12z as a significant spike was shown mid august for London, likely an outlier but maybe a clue to something bigger?

[Summer Sun]

A northern blocking system of sorts starting to develop slowly.

http://www.wetterzen...s/Rtavn1921.png

http://www.wetterzen...s/Rtavn2401.png

http://www.wetterzen...s/Rtavn2641.png

http://www.wetterzen...s/Rtavn3121.png

Not a bad set-up after this weekends blip with the low pressure. No heatwave but it wouldn't be bad the south would probably fare best temperature wise. As ever cloud and rain could be an issue at times.

[PubliusEnigma]

A northern blocking system of sorts starting to develop slowly.

http://www.wetterzen...s/Rtavn1921.png

http://www.wetterzen...s/Rtavn2401.png

http://www.wetterzen...s/Rtavn2641.png

http://www.wetterzen...s/Rtavn3121.png

Not a bad set-up after this weekends blip with the low pressure. No heatwave but it wouldn't be bad the south would probably fare best temperature wise. As ever cloud and rain could be an issue at times.

Indeed, very much a southerly tracking jet from Friday this week, whilst north westerlies usher in a much cooler

set up, the jet ramps up to our south

Keeping us locked out on the cooler side, whilst the whole of the rest of Europe, 250 miles South east of the channel coast of France

seem so stay in endless summer. Looking like quite a run of unsettled weather from the beginning of the second week of august for possibly

some time. With High pressure remaining high towards Greenland, a changeable outlook seems most likely, with mild summery days for the S and

SE interspersed with unsettled spells, always with the most rain in the N and NW.. GFS teases us with a few warmer days in 10-14 days time,

however the GFS hasnt been overall the most reliable of late, so very much in the realms of FI.

Having a quick look at Jay Wynnes further outlook for august, he paints a very changeable outlook, indicating summer could be over by tomorrow/wednesday ;-

Monday 8 August 2011 to Sunday 14 August 2011

Changeable

Westerly winds will dominate this period. There should be some sunshine for most places but not all day for everyone. The south and east of the UK will probably see the best of the sunshine while the north and west are most likely to see some showers or more persistent rain, with the winds picking up at times. It may start off quite warm but generally temperatures will be close to the average, so still some pleasant conditions, especially in the south and east.

Monday 15 August 2011 to Sunday 28 August 2011

Unsettled

There is a strong signal for cyclonic conditions to be the driving force behind the weather. We can expect to see outbreaks of rain, some drier interludes and near normal temperatures. The best of the dry and bright weather is likely to be in the south and east of the UK with most of the rain in the north and west, where it may be windy at times.

Next week

Will it warm up again in September?

Edited August 1, 2011 by PubliusEnigma

[Summer Sun]

Pressure slowly rises from next Tuesday,

http://www.wetterzentrale.de/pics/Recm1921.gif

http://www.wetterzentrale.de/pics/Recm2161.gif

http://www.wetterzentrale.de/pics/Recm2401.gif - Greenland Looks Good

This may not last long if the high pressure can't establish it's self with plenty of low pressure still around.

[Gibby]

Good evening.

GFS this evening shows pressure falling slowly over the oncoming days. With very warm humid air over the UK outbreaks of thundery rain or thunderstorms are possible within the next 48-72hrs. The risk is most prevalent for Northern regions late tonight and at first and again later tomorrow plus perhaps more widely on Wednesday into Thursday. From Thursday cooler and fresher air is shown to ease in from off the Atlantic as winds turn westerly. Then over the weekend and early next week a deep summer depression moves NE over England and on away to the NE. Heavy rain and strong winds would sweep across England and Wales followed by cool NW winds and squally showers over Sunday and Monday. Then in the Low resolution part of the run pressure rises somewhat with showers and winds easing to dry weather with sunny spells by day 10. The end of the run shows high pressure migrating slowly east over the UK with a slow fall of pressure again by the end of the run.

UKMO tonight looks very showery. After a couple more days of light winds with humid air and high temperatures thundery rain could break out from now on principally in the North tonight and later tomorrow and in east and southeast Britain on Wednesday. Other areas could also see some rain with cooler fresher air moving east through the UK by Thursday leaving the end of the week more comfortable with a mix of sunshine and showers, heaviest in the North and West.

ECM looks much the same with a warm and sultry few days with thundery rain from a small depression crossing NE over Southeastern areas on Wednesday with cooler fresher air moving into all of Britain in its wake by Thursday. The end of the week, weekend and start of next week is shown to remain very changeable with heavy showers and sunny intervals with near normal temperatures for all. As low pressure deepens as it moves away NE a cool NW flow develops for a while before a slow improvement takes shape from the SW towards the end of the run with lighter winds and fewer showers.

The charts remain stubbornly unsettled looking tonight with a return to temperatures close to normal after the heat of the next few days in the east and south. Rain and showers is shown for all from all models with something of an improvement albeit probably temporary shown for the period around 10 days time.

[PubliusEnigma]

The charts remain stubbornly unsettled looking tonight with a return to temperatures close to normal after the heat of the next few days in the east and south. Rain and showers is shown for all from all models with something of an improvement albeit probably temporary shown for the period around 10 days time.

It wont be rain and cloud all the time, they'll be some midler sunny intervals specially towards the SE.

[damianslaw]

Short term - next 48 hours, humid everywhere as we see warm continental sourced air mixing with tropical maritime air from the south/southwest pumped up by a slow moving trough and associated low pressure to our west. Come Thursday a marked change to cooler fresher conditions thanks to strong heights ridging southwest out of Greenland forcing the trough and low pressure to swing southeastwards into the country. Thereafter, the three main models are painting slightly different scenes, GFS keen on deepening the low pressure by the weekend ushering in a potentially windy spell of weather for the north and west. UKMO is showing a less intense low pressure system with showery conditions at best. ECM a bit of a half way house between the two.

Longer term - all eyes on the Greenland high, the models are hinting at weak pressure rises near the country early next week meaning a possible transient high development before the next atlantic system moves in on a southerly tracking jet. If the greenland ridge is strong enough we could end up in another slack northerly flow again, but it has to be said the atlantic does look like it has some energy about killing the chances of any real robust ridging out of Greenland and conversely enabling cyclonic conditions to take hold.

[MP-R]

As damianslaw says, a general pressure rise after a brief unsettled spell at the weekend though. The GFS certainly doesn't have anything of major Atlantic systems after the weekend with a largely dry run if not always sunny. Probably average-warm conditions with a flow increasingly swinging around to the east.

[Gibby]

Good morning.

GFS this morning shows the current very warm and humid air over the UK being displaced over the next 48hrs by a cooler westerly flow from off the Atlantic. With pressure Low in the vicinity of the British isles will occur on most days with winds turning NW or North by early next week with cool conditions in exposure. In the lower resolution part of the run this morning High pressure remains focused in Mid Atlantic with a slack airflow becoming established again over the UK with more heavy sometimes slow moving showers each day with normal temperatures generally.

UKMO also shows the displacement of very warm and humid air in 48hrs or so to light westerly winds and increasingly showery conditions as we move towards the weekend. Innitially showers will be well scattered apart from the chance of some thundery ones late tomorrow and early Thursday in the SE as the cooler air interacts with the very warm and humid air over the SE. By the weekend showers will be widespread and heavy at times but with some warm sunny spells inbetween.

ECM looks a little better in the longer term with the same showery picture taking us into early next week with quite a potent Low shown near the Baltic early next week bringing cool and showery NW winds to us for a while before a strong rise of pressure from the south brings us into a NW/SE split to end the run with SW and rain at times for the North and far west while the south and east become drier and more settled with a recovery in temperature too.

In Summary the breakdown to cooler, fresher weather looks fairly uneventful for most in the coming two days with some dry, very warm and humid conditions being steadily replaced to cooler, fresher conditions behind a weak cold front crossing east late tomorrow. The far SE may see something thundery from it tomorrow night though. Afterwards all models show a showery spell though as always some places will miss them and stay dry. In the long term GFS keeps things showery and slack through FI while ECM still wants to build pressure close to the south in a week or so with warmer, more humid conditions but still with some rain in the NW while areas further South and East see the best of dry, bright conditions away from Western coasts and hills.

[Frosty.]

The Ecmwf 00z is looking very unsettled for the next week or so, especially later this week and through into early next week with a lot of rain although most of the rain looks like being across northern britain but some heavy downpours in the south too, the heat and humidity across the southeast will be replaced by fresher atlantic air by friday but the ecm indicates that the south could warm up again in FI with high pressure across the near continent which could possibly extend it's influence across more southern parts of the uk but the north & west look more unsettled which has been the story of the summer so far with no sign of any nationwide anticyclonic spells predicted in the next few weeks, early next week could actually be windy with strong NNW'ly winds which would make it feel quite autumnal..should it occur.

[shedhead]

Move along, move along please, there's nothing to see here.... well not if you are looking for a protracted fine, dry and sunny spell of weather as we enter the last 4 weeks of offical Summer. Both the main models offer nothing other than unsettled conditions and with winds swinging into the northwest it will also become rather cool for many, especially in and around showers. ECM do have signs of more ridging post T+168hrs, but even then only southernmost counties look set to benefit, with most other areas seeing cloud and more persistent rain/drizzle.

Edited August 2, 2011 by shedhead

[mushymanrob]

As damianslaw says, a general pressure rise after a brief unsettled spell at the weekend though. The GFS certainly doesn't have anything of major Atlantic systems after the weekend with a largely dry run if not always sunny. Probably average-warm conditions with a flow increasingly swinging around to the east.

yeah, how odd... the ukmo, fax and ecm all have only a ridge with another low drifting in off the atlantic and introducing some very warm uppers (ecm that far out) as the ridge drifts and is centred over france. the gfs is having non of this 'other' low, it builds pressure to our west and leaves is in a drier, cooler, northerly.

[shedhead]

yeah, how odd... the ukmo, fax and ecm all have only a ridge with another low drifting in off the atlantic and introducing some very warm uppers (ecm that far out) as the ridge drifts and is centred over france. the gfs is having non of this 'other' low, it builds pressure to our west and leaves is in a drier, cooler, northerly.

Agree, there are some rather marked variations shown as we get past the reliable. However the one thing all the models are firm on at T+144hrs is another robust block over Greenland, as we've seen through much of this summer to date, so expecting any significant change to the overall July pattern looks nothing more than hopecasting to me.

[feb1991blizzard]

yeah, how odd... the ukmo, fax and ecm all have only a ridge with another low drifting in off the atlantic and introducing some very warm uppers (ecm that far out) as the ridge drifts and is centred over france. the gfs is having non of this 'other' low, it builds pressure to our west and leaves is in a drier, cooler, northerly.

Its on the low side of the ensembles and with no support from any other model or the FAX it isnt going veryfy although if it did it would keep us fresh until mid month.

[feb1991blizzard]

Agree, there are some rather marked variations shown as we get past the reliable. However the one thing all the models are firm on at T+144hrs is another robust block over Greenland, as we've seen through much of this summer to date, so expecting any significant change to the overall July pattern looks nothing more than hopecasting to me.

Yes. i what i would say is that although the ECM evolution looks far more likely, the building blocks are there for a Northerly at some point during August.