Usual rules. Stay on topic and sensible. Off topic crap and ramps will be deleted without warning.


Proceed....

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Good evening. Here is the report on the 12 midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday August 2nd 2013.

All models show High pressure close to the South over the next 48hrs while a Westerly flow remains over the North with thicker cloud and rain over the far NW. By Thursday a cold front meanders SE across the UK reaching Wales by the end of the day. A band of rain will accompany this frontal band weakening and breaking up later on Thursday. By Friday and the weekend Low pressure develops close to the East coast as a Northerly flow blows down across the UK with showers or outbreaks of rain for many, especially towards the East and South. After a very warm few days for the South and East of Britain temperatures will fall closer to average over the weekend.

GFS shows Low pressure to the South of Britain on Sunday which gradually feeds NW towards the NW of Britain through next week giving rain and showers for many off and on, As it arrives near NW Britain near midweek it weakens into no more than a trough by the end of the week as High pressure builds in briefly from the West. Low pressure then winds up to the North at the end of the run affecting all areas with rain and wind at times.

The GFS Ensembles show the weather becoming more unsettled in the South at the weekend with rain or showers lasting off and on for the rest of the run. The North looks like there will be less rain and warmer conditions with temperatures which will be well above the seasonal normal especially in the North.

The Jet Stream shows the flow currently to the North of the UK buckling South over the UK around a small Low South of the UK at the weekend. This cut off flow decays later as the northern arm strengthens and crosses East across the UK at the end of the run.

UKMO shows Low pressure over the UK at the beginning of next week with unsettled conditions with heavy showers or outbreaks of rain in rather cooler conditions.

GEM shows a Low pressure area across the UK at the end of the weekend and the start of the month drifting slowly West back out into the Atlantic with progressively drier and warmer weather in SE winds drifting in from the East.

NAVGEM shows a complex Low pressure area forming over the UK at the weekend and well into next week with heavy showers and some longer spells of rain in cooler temperatures than of late looking likely.

ECM tonight shows a complex Low pressure area developing over or near Southern England too at the weekend with rain or showers  while the North sees some longer drier spells. Later in the run the Low complex shifts North with a slack showery Westerly flow developing in 10 days time with the showery theme reaching the North too.

In Summary the weather is now almost certain to change later in the week. There will probably 3 more days of fine summerlike conditions across the South and East of the UK before Low pressure develops near Southern England at the weekend and looks like wanting to go nowhere fast. There looks likely to be showers or outbreaks of rain in rather humid air for many. However, the North will be fairly close to High pressure to the North  at times with fine and dry weather more likely to occur here than elsewhere.

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Thanks martin i think.

Thanks Martin.

very dry here could do with a drop of rain.

 

With GFS and GEM developing LP some way south of the UK, ECM having a vague mess across the UK, and UKMO actually managing to get the Atlantic westerlies in on day 6, there is very little confidence to be had regarding the weather from Friday onwards.

...so to pull out a cliché, more runs needed!

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gm may be on to something thats some T Depression to our n/w others cant c it yet.

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=186&mode=0&carte=1

would not want to wind surf throu that

No point in more runs at the moment - they would just compicate matters even further. Patience the only solution likely to verify!

ukmo looks very unsettled later on parts of s and s/e as Martin says and looking at ending on fax charts

 

http://www.meteociel.fr/modeles/ukmo2.php?ech=120&carte=2000

 

http://www.wetterzentrale.de/pics/Rmgfs1504.gif

Very nice and warm this coming Sunday.  Saw the big change on today ensembles to above average all the way meaning around low to mid 20's in first half of September.

Just to illustrate the uncertainty, most of the above links appear to be out of date and at cross purposes with the accompanying comment as soon as they're posted!

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Good morning. Here is this morning's report on the midnight outputs of GFS, the Fax Charts, UKMO, GEM, NAVGEM and ECM for Tuesday September 3rd 2013.

The pattern is well set now with High pressure close to Southern Britain pulling away East over the next 48 hours maintaining a warm and drier feed of air across Southern areas later today and tomorrow. At the same time the cloudier North will come under attack from a cold front moving SE from the NW later tonight and tomorrow. This trundles slowly SE through Wednesday and Thursday reaching Wales and the NW of Britain by Thursday. the rain innitially heavy will become lighter and patchier the further SE it comes. By Friday and the weekend the trough will rejuvenate with Low pressure forming close to Southern Britain with outbreaks of rain and showers and much cooler temperatures arriving over the UK at the weekend.

The Fax Charts chart the sequence of events well with Low pressure close to SE England at the weekend with some heavy showers or more general rain affecting the South and East in particular in much cooler winds blowing down from the north or NE.

GFS shows the Low further West at the weekend but the net result is no different next week with a complex Low pressure area over the UK with rain at times and close to average temperatures at the surface. Some of the rain could be heavy and thundery in places. Through the final week of the run the weather improves as the Low fills and becomes replaced by High pressure building in from the West with sunny and warm conditions for all again with the likelihood of fog by night.

The GFS Ensembles show cooler weather at the weekend with rain at times for all. the trend then is for rather changeable conditions with rain at times though most members point to dry and bright weather at times too. The operational was a warm outlier at the end in the South and more widely in the North though temperatures up here are shown to be well above average at times.

The Jet Stream shows the general flow to the North of the UK at the moment. The Southern half of this flow splits and feeds our surface Low at the weekend with a core of winds going South of the UK. this gradually weakens as the low fills and moves towards the NW and sets up a new surge of Jet energy blowing West to East in the vicinity of Northern Britain later in the run.

UKMO today shows Low pressure moving North and NW across Britain early next week with showers or outbreaks of rain in the South extending North to all areas early next week.

GEM holds Low pressure down to the SW for some considerable time with showers and rain more likely in the South. The trend then is shown for this to fill and move NW to the west of the UK with warm and slack SE winds across the UK which could mean rather warm weather returning as High pressure lies over Central Europe.

NAVGEM also keeps quite a deep Low close to SW Britain next week with rain and showers extensive across Southern and SW parts while Northern and NE areas will see the least rain and drier conditions.

ECM also holds Low pressure down near the SW for much of next week with rain and showers in abundance for the South and SW where it would be progressively drier and brighter the further North and east one travels though Eastern coasts could be rather grey and misty. Late in the period the Low to the SW fills and moves across the UK as a trough at the end of next week with showers for all as it does.

In Summary the models continue to firm up on giving Southern Britain a taste of more unsettled conditions for at least a time while the North may turn out not as wet as further South as something of a North/South split in reverse develops. Longer term it looks less clear cut with the likely option for the Low to the South or SW to move North later next week which could either open the door to the Atlantic westerlies with rain at times or give the Azores high a chance to regain control over the UK again as GFS suggests possible this morning. there is a lot of weather to get through during  the next 7 days before anything can be confidently predicted for the following week. The unsettled spell in the coming week though is now looking more confident to happen now as most models have got a handle on developing Low pressure close to Southern Britain in one guise or another.

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Thank you Martin.

 

Looks like rain/showers Friday until at least Tuesday of next week..For this area.

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It seem they cannot handle slack LP well than deep LP so in my view it looking fine to me this weekend as in past experience with slack LP over SW or W does not bring any rain here but mostly dry, warm and humid with risk of few thunder showers.

I think a new record has been set for the most uncertain day 5 outlook of all time!

Impossible to call this one in any detail at all, and the knock-on effects are also considerable in terms of where HP can build near (or over some parts of) the UK - which is important for the kind of airmasses we experience.

Unsettled conditions are far more favoured than settled in the south in particular, but beyond that we're clueless

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Hi all,

Here's the September month ahead forecast;

http://www.gavsweathervids.com

A very hard month to call as September always is.

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My feelings as well.

I know what you mean.

 

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A few hours on and the models are still chopping and changing.

Given the 12z runs I'm not even sure that the North-South split is at all certain.   The models are really struggling with the upper trough.  ECM, UKMO & GFS all have a cut-off upper low around the Irish Sea/NW Scotland at T+96.  The evolution to a deepish low pressure around Biscay has been dropped now.

A sharp cooling off for eastern England on Friday looks pretty certain now, along with some rain/showers as a surface low forms somewhere over eastern England.  The weekend looks as hard to call as before but with perhaps a trend towards less rainfall for the south-eastern quarter.

 

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Good evening everyone. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday September 3rd 2013.

All models show 24-48 hrs more of the current summer spell of weather currently being enjoyed by Southern and Eastern Britain. The cloudier West and North will see at least some brightness and warmth tomorrow as drier air currently arriving across the South extends further North. With still air and September nights fog is a rank certainty in the current setup and tonight will be no exception, mostly across the South of Britain. Through Friday and the weekend the weather transforms itself quickly as a front strengthens over Eastern England as Low pressure forms across it on Friday. Many areas will become substantially cooler on Friday with spells of thundery rain and a chill North wind. The weekend may see more showery conditions and less cool weather but some of the showers will be heavy slow moving and thundery as Low pressure looks like lying over the top of the British Isles.

GFS then shows changeable conditions throughout next week and the end of the run with various areas of Low pressure and fronts never far from the UK. There would no doubt be some dry and bright weather from time to time but it would not to be relied upon as further rain or showers would most certainly arrive within days on the basis of tonight's GFS operational output. Temperatures would be close to average for much of the time but in any prolonged periods of rain it would feel chilly.

The GFS Ensembles show some very warm uppers over the coming days before a marked cool down with much spread thereafter. There will be rain accompanying the fall off reducing in quantity the deeper into the run we travel both North and South. The operational was a cool outlier late in the run in the South.

The Jet Stream shows a split in the flow over the coming days with the split encircling the UK in association with the UK Low pressure before settling on a West to East flow across the Atlantic and over the British Isles.

UKMO tonight shows Low pressure well established over the UK early next week with rain or showers scattered about the entire UK and temperatures well down on recent values.

GEM tonight shows Low pressure making Southern Britain it's home next week with spells of rain and showers encircling around the Low pressure over Southern Britain and some areas further North too at times while the far north stays drier and brighter and possible rather warm in the sheltered West and in any brightness.

NAVGEM too keeps Low pressure close to the SW with rain at times in the South and SW. Northern and some Eastern areas will be the best places to see the best of the dry and brighter conditions available.

ECM tonight shows Low pressure clsoe to SE England at the weekend moving NW then back SE next week maintaining several days of cloudy weather with showers or outbreaks of rain in places with nowhere immune. Later in the run pressure builds again from off the Atlantic with dry and bright weather returning for many to end the run.

In Summary tonight the pattern looks like becoming quite complex once the certainty of Low pressure at the weekend arrives. With such a cut off Low centre it could drift almost anywhere with the models illustrating different positions between them for the Low centre with any resulting longer term predictions of the weather beyond next week foolhardy at this range and given that such complex synoptics that will be in place next week. I think we can expect many ups and downs between the models on the events beyond next week over the coming days before an eventual agreed pattern emerges.

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When was the last time the nwp did a good job with a trough? I hope things sort themselves out soon as it wont be so long before the winter sypnotics come over the horizon. if this split energy conundrum is still around come november, gawd help us.

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ECM looks very nice.

http://www.jp2webdesign.co.uk/ds/ecm.htm

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ECM now lifts the weekend trough out pretty quickly into next week, and UKMO isn't far behind.

GFS and GEM keep the trough to our SW and then bring it back east for round 2.

The only common signal from them all is for high pressure to try and regain influence once the trough has cleared off. It's either going to be that or the Atlantic finding a way to us. Obviously a new ridge of high pressure is far more desirable after a period of rain and showers such as we're looking at for 2-5 days from Friday.

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Good morning. Here is today's edition of the review of the midnight outputs from GFS, The Fax Charts, UKMO, GEM, NAVGEM and ECM for today Wednesday September 4th 2013.

All models show a High pressure area exiting the SE of England today on its way across Europe. Very warm air around this feature is shown to blow North across the UK today with dry and sunny weather away from the NW where a front approaches later in the day with attendant occasional rain. Through tonight and tomorrow this is shown to move slowly SE across Britain reaching Northern and Western parts of England and Wales by evening and areas further East and SE overnight. On Friday a Low pressure forms near the East in association with this front intensifying the rainfall across England and Wales and dragging cool Northerly breezes across all areas. All models then show Low pressure close to the UK over the weekend with rain or showers for all at times.

The Fax Charts show the general progression of events listed above as troughs move down from the NW and develop a Low pressure close to SE England within it's core deepening and spiraling rain and showers across the UK over the weekend in much cooler air.

GFS begins next week with Low pressure over Southern Britain where it is maintained for most of the week with showers each day across the South whereas the North remains more likely to see less showers and longer drier spells in average temperatures. By the weekend a NW flow develops behind the final exit of the trough over the South renewing the trend towards drier conditions as High pressure from the SW again becomes influential with dry and benign weather. A hint of something a little more changeable again is hinted at by the end of the run.

The GFS Ensembles shows temperatures over the South reverting close to the seasonal average from the weekend with rain at times. The North is shown to maintain 850 temperature values more likely above average although this may not always be reflected at the surface given cloud and possible rainfall at times which is shown Nationally from Friday. The spread is slightly less big this morning apart from the customary wide spread at the end of the run.

The Jet Stream splits from it's flow north of the UK in the next few days as it cyclonically blows around the UK in the area of the cut off low over Southern Britain at the weekend. It takes a long time for this to simplify into a more direct West to East motion across the UK later in the run.

UKMO today shows Low pressure having been over the UK for some days exiting East on Tuesday with High pressure building from the West. Tuesday is still likely to be showery across the UK but these will probably die out from the West through the day.

GEM today shows low pressure over the UK sinking away South having spent several days over the UK giving rain and showers for all. By the end of the run with the Low having shifted its axis down to the SW and High pressure over Scandinavia it's the SW who would maintain the risk of showers while Northern and Eastern areas become dry and quite warm in the sheltered west as any sunshine breaks through.

NAVGEM shows the Low filling in situ over the UK next week maintaining showery weather for all for some considerable time lessening by midweek as pressure begins to rise from the SW squeezing the remaining life out of the feature with drier and brighter conditions developing.

ECM shows High pressure building back NE strongly next week as the Low moves East across the UK in the form of a trough early in the week followed by dry and fine weather with overnight mist and fog likely in the South while the far NW may stay cloudy in a slowly imcreasing SW wind in 10 days time.

In Summary the models are really struggling with the sequence of events from as early as this weekend. As is usual in September as seasonal cooling takes place across the Northern hemisphere synoptics can often become complex and then add the injection of ex tropical storms in the Western Atlantic and you have the ideal cocktail for some wildly fluctuating synoptics shown from run to run and more certainly model to model. That is exactly what we have this morning with everything shown this morning ranging from the return of late Summer from ECM next week to the more unsettled and potentially thundery GEM for the SW with pressure High over Scandinavia. There is a bias slightly towards High pressure building back from the SW later next week but until I see this still being shown at the weekend's output and because of the uncertainties I have noted cautious optimism to this evolution might be the best approach. 

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Thanks GIBBY, as always. 

Thank you Martin

In the balance

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