Model Output Discussion - September Onwards

[Summer Sun]

People may be overlooking a certain little feature expected to race north through Ireland Sunday- Monday

With the speed its moving, and potential intensification, it is of high interest to me.

No one is over cooking anything, ECM tonight is stunning

http://www.wetterzentrale.de/pics/Recm961.gif

http://www.wetterzentrale.de/pics/Recm1201.gif

http://www.wetterzentrale.de/pics/Recm1441.gif

http://www.wetterzentrale.de/pics/Recm1681.gif

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

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

http://www.wetterzentrale.de/pics/Recm2401.gif

A late heatwave is getting ever closer.

[Gibby]

Good evening folks.

GFS tonight shows the weather remaining a little bit unsettled between now and Monday with weak troughs bringing some rain to the westernmost regions and perhaps a litle more widely late Sunday. Thereafter the model shows high pressure developing strongly to the east drawing very warm air North from Europe. This extends to most areas through next week with sunny days for many with temperatures of 18C-21C in the North and 21C-25C further south and east and no doubt some localities could exceed that in the SE. In FI pressure remains high with subtle differences in its location being responsible for a lowering of temperatures with time and increasing the risk of overnight fog and mist.

UKMO also shows the weather warming somewhat in the short term while the main warm up phase occurs from next Monday on. Between now and Monday the weather remains rather mixed with variable sometimes large amounts of cloud and a little rain in the far west on Saturday and possibly more widely late Sunday and early Monday. Thereafter, skies brighten with sunny spells for many as temperatures top the 70's for many, though with a slight tilt to the winds toward SW in the NW more cloud and lower temperatures could be experienced here.

Finally ECM sings from the same hymn sheet too with the warm up starting from now but with the caveat of more cloud and a little rain for some on Saturday and late Sunday from weakening troughs moving through from the west. From Monday on things warm up markedly as High pressure develops strongly to the east of the UK with prolonged sunny spells lifting temperatures into the low to mid 20's for many through next week. As the run moves through next weekend as with GFS the high moves west to be centred close to the North of the UK with temperatures slowly falling both by day and night with an increasing risk of mist and fog night and morning.

In Summary tonight it looks more than certain now that things are going to warm up markedly next week with all models showing similar synoptics. There is very little rain shown after the weak troughs of the weekend shift out of the way. With the models showing warm air from Europe wafting up over the UK from Monday some unseasonably high temperatures seem possible for several days later next week in strong early Autumn sunshine. In the longer term high pressure remains firmly in control with a shift in positioning cutting off the warm southerly drift and allowing a slow day to day fall off in temperatures exacibated by the increased likelihood of mist and fog overnight, slow to clear for some. Nevertheless, we could experience some of the best weather of the summer or ironically since Spring so lets hope the charts continue to favour similar options over the runs and days to come.

[Tim Bland]

Some of the charts are not far off the September 1895 set-up. That was a remarkable heatwave

This doesn't bode well for the coming winter! The winter of 1895/6 was snowless. It looks as if the high is further west this time and WAA up into Greenland can only be a good thing.

Edited September 22, 2011 by Tim Bland

[ANYWEATHER]

What we all have to be careful of is getting to carried away with the output! For those Winter and Summer lovers you know what Im talking about. The predicted "Autumn Heatwave" is still in the realms of FI and there are lots of "Ifs Wheres and Whens" to go first before we get to that point!YES, there is a definite warm up on the cards, but from "Experience" I know how it can go belly up when expecting what the models say! ...and how dissapointing you feel.! But look at the latest output from Ecm and Gfs down below and ""If"" that came off we would be talking record breaking warmth in some places.

[Andy Bown]

No one is over cooking anything, ECM tonight is stunning

A late heatwave is getting ever closer.

Matty said 'over looking' not 'over cooking'.

As in overlooking the LOW that zips through late Sunday/early Monday and not overcooking the expected warmth.

[Summer Sun]

Some of the charts are not far off the September 1895 set-up. That was a remarkable heatwave

How nice that would be for winter, just about everywhere would be snowless, so apart from overnight frost's it would be dry and sunny.

[rob48]

Damn!

Booked a farm cottage as base for a walking holiday next week and it looks like it's going to be spoiled.

Nearly a year of perfect weather (except for lack of rain) and I'm about to cop for mid 20's by the look of it.

At least it shouldn't be humid, just too dry.

Edited September 22, 2011 by rob48

[summer blizzard]

The warm, anticyclonic spell does indeed now look nailed on through to day 10 with maxima peaking around 25-27C.

What is of interest to me is that both the GFS18z last night and ECWMF12z tonight and even the GFS12z tonight to a degree all retrogress the high westward toward Greenland by 240 hours. What this means is the eventual outcome in early October could be a northerly or if pressure remained high, a cool high pressure.

[ribster]

No one is over cooking anything, ECM tonight is stunning

A late heatwave is getting ever closer.

Charts that haven't occurred yet, often are stunning, and I'm not saying we won't get some pleasant warm weather, but I've lost count of the number of times 'nailed on synoptics' have collapsed inside 48 hours, and yes that's with cross model 'unanimous agreement'.

[kold weather]

ECM is very impressive tonight, as others have said mid 20s, maybe the isolated 28C judging from the uppers.

I'd imagine night time temps would drop away towards the end of next week.

[Liam J]

Are we looking at synoptics that could break records for temperatures? The highest ever October temp recorded was 29.4 on the 1st October 1985 in Cambridgeshire.

[Geordiesnow]

ECM is very impressive tonight, as others have said mid 20s, maybe the isolated 28C judging from the uppers.

I'd imagine night time temps would drop away towards the end of next week.

To be honest, I would think night time temps will be at their lowest on Monday night with the high ridging in over cool uppers and from then on in, the warm uppers get pushed up Northwards and nighttime temps will be very mild despite clear skies due to the high dewpoints.

Models have shifted towards more of a SW'ly airflow but with high pressure firmly in charge which means that the far west is in risk of any frontal cloud and any South-Western facing coasts could get alot of low cloud and sea fog occuring with it struggling to burn back.

All this talk about this being nailed on for the next 10 days is rubbish, you can't be sure of how the Atlantic will react and the models could easily start switching for the Atlantic to edge in closer with each run. However at least for Monday(for some not all) and Tuesday, the weather will be settled and sunny with temperatures warming up day by day.

[damianslaw]

The warm, anticyclonic spell does indeed now look nailed on through to day 10 with maxima peaking around 25-27C.

What is of interest to me is that both the GFS18z last night and ECWMF12z tonight and even the GFS12z tonight to a degree all retrogress the high westward toward Greenland by 240 hours. What this means is the eventual outcome in early October could be a northerly or if pressure remained high, a cool high pressure.

Yes an unusual set up being shown for next week in terms of the time of year. I would not at all be surprised if we quickly exchange a very warm southerly for a cold northerly - low heights will be forced to ride around the edge of the high down its eastern side thus forcing heights to retrogress towards Greenland - often southerlies can quickly become northerlies and vice-versa, the trend being shown by the models to retrogress the high NW I think will continue in the coming days, so yes whilst we could see some very warm weather for a few days, there is a strong chance of things cooling down markedly thereafter due to a projected very quiet atlantic enabling retrogression NW.

[Milhouse]

Yes an unusual set up being shown for next week in terms of the time of year. I would not at all be surprised if we quickly exchange a very warm southerly for a cold northerly - low heights will be forced to ride around the edge of the high down its eastern side thus forcing heights to retrogress towards Greenland - often southerlies can quickly become northerlies and vice-versa, the trend being shown by the models to retrogress the high NW I think will continue in the coming days, so yes whilst we could see some very warm weather for a few days, there is a strong chance of things cooling down markedly thereafter due to a projected very quiet atlantic enabling retrogression NW.

Several outcomes still remain possible regarding where we go following next weeks warmth but i think its is too far ahead to be saying what is most likely to happen. We will obviously find out in due course. The ECM mean has pressure remaining the highest over central Europe, and as the ECM 12z suggests, there will likley be considerable variation shown by the individual members. Some bringing in a cooler northwesterly by day 10, and others maintaning the southerly flow or having the high directly over the UK.

http://www.wetterzentrale.de/pics/Reem2401.html

[skifreak]

3 months to the day from Mr Data's chart....

[snowlover2009]

It is nailed on that summer will make one more return and that will probably be it. Of course we can expect more dry sunny days, but any real warmth, then this will probably be it, summer temperature wise IMO. The charts do look juicy, but so sad they didn't occur during summer, even the start of September it could have brought us mid to high 20s widely.

I have to say though, the discussion above about how similar this upcoming spell is to the last week of September 1895 is extremely interesting IMO. Not only is it occurring on the same week and nearly the same days, but looking through the october archive, I wouldn't believe that it would go from this:

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118950925.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118950926.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118950927.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951001.gif

to this:

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951020.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951021.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951022.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951023.gif Snow showers

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00218951023.gif

http://www.wetterzentrale.de/pics/archive/ra/1895/Rrea00118951025.gif Wow

So it could turn out to be an interesting month, the similarities are uncanny. This is not an insult to anyone, but all I have to say is, for those who think it could be a long lasting event throughout, you only need to look at the above, to see how much things can change. But for now enjoy out late summer or indian summer!

[Bottesford]

Cracking output this morning with a deep southerly flow taking hold during Tuesday/Wednesday staying firm right up to the weekend where we hit FI.

Before then warming up but not as warm as it'll be mid to late next week.

Could be on for 26 maybe 27c in some places during Weds/Thurs.

Wonderful stuff!

[Gibby]

A little later than usual today but nice to see the warm spell is still very much on.

GFS remains unchanged in the short term from yesterday with a big warm up next week after a few weak troughs delay things a little for some over the weekend. As we move through next week a warm Southerly flow delivers some unseasonal warmth under sunny skies. By the weekend weak low pressure drifts close to the west which in FI ends the spell with rain at times and consequently much cooler weather. However, for the next 7 days or so a lot of dry and very warm weather (eventually) seems likely.

UKMO today also looks very good once the weak troughs clear out of the way by Monday. With high pressure then centred over North Germany and Denmark warm continental air drifts NW to all but the far NW where with a slight SW element to the wind things would be cooler and more cloudy at times For elsewhere though temperatures would soar into the Low to possibly mid 20's by the middle of next week.

The Fax Charts show troughs affecting the North and West at times with two cold fronts bringing more cloud and some rain (but little if any rain from the first one) to other areas over the weekend. At the beginning of next week high pressure develops rapidly pulling warm air North from Europe by Tuesday.

ECM also looks very good for warm weather. The same sequence of events occurs between now and Monday as the other models show. Then with high pressure resident over Europe warm SE winds bring sunny and very warm conditions to all. The one caveat is that winds could tilt more easterly with time bringing slightly cooler air in though still very pleasant conditions overall.

It still looks very good for a decent early Autumn warm spell next week. Changes in synoptics this morning are small but could be significant should the wind become more easterly than southerly with temperatures suppressed below the very high category we were seeing yesterday. However, that aside and the GFS breaking things down in a week or so it still looks very good for most next week with plenty of scope for warm and sunny conditions to end what has been a quite disappointing summer for hot weather.

[Liam J]

The much talked about warm and settled spell is still very much on course to arrive next week, excellent cross model agreement on a significant warm up with air sourched from Southern Europe.

At least you won't need sun screen on and it won't feel to hot as the sun is much weaker as we enter October and the shorter days will spoil it also - A different story if this occured 2/3 months ago.

Be nice to get out and about in the evenings with the dogs without having to wear wet weather gear! You never know maybe even the shorts can come out of their winter holiday.

[Nick F]

At least you won't need sun screen on and it won't feel to hot as the sun is much weaker as we enter October and the shorter days will spoil it also - A different story if this occured 2/3 months ago.

I would still slap on suncreen, although the sun is weaker now than back in May/June/July, A UV index of 2-3 is still achievable across England and Wales next week, so you will still burn (albet slowly) out in the mid-day sun.

On to the model output, 00z ECM seems keenest to keep the ridge influencing the UK weather into the depths of FI, whilst 00z GFS has a slow breakdown from the west. ECM disrupts the Atlantic trough into a cut-off low which allows stronger heights/pressure to maintain across the UK, while GFS is more progressive with the Atlantic trough keeps it intact and moving in across western UK by next w/e.

00z 8-10 day H500 comparisons show these differences between the 2 models:

[TonyH]

Looking like a possibly exceptionally warm last fews days to September/ start to October, the Midlands record under threat (27c in Coventry in 1985)?

Edited September 23, 2011 by Tonyh

[No Balls Like Snow Balls]

Well out in FI but yes please, it has been suggested on more than a few runs that after the warm spell the high may well move NW allowing a NW/N of some sort and would tie up with the Meto 30 day outlook of becoming colder.

[Radiating Dendrite]

Well out in FI but yes please, it has been suggested on more than a few runs that after the warm spell the high may well move NW allowing a NW/N of some sort and would tie up with the Meto 30 day outlook of becoming colder.

Just like the charts we were seeing at the start of winter last year!

[Thundery wintry showers]

Not sure about that- the chart has cold potential but the airmass over the UK is still pretty warm with the Arctic airmass shunted out east. I also think the alignment of lows and highs is quite improbable- it is out in GFS FI after all.

Today has turned out a bit cloudier in the North East than I expected, and the weekend is looking like it will have a NW-SE split due to the tropical maritime south to south-westerly flow. Most of eastern and southern England will be dry, with some sunshine at times, but elsewhere quite a cloudy muggy weekend with some bits and pieces of light rain. But after this weekend's Atlantic low moves through, that's when we'll see the high pressure ridging further north and west and taking the warmer, sunnier weather north and west with it across most other parts of the country.

Temperatures mid to late week do look like they won't be far short of those observed on the 1st October 1985. I doubt that the intense warmth will be sustained enough to challenge that October record (the hottest airmasses will probably be mixed out a touch from the SE and/or SW by then) but 28/29 September could well end up about as warm.

[Don]

Well out in FI but yes please, it has been suggested on more than a few runs that after the warm spell the high may well move NW allowing a NW/N of some sort and would tie up with the Meto 30 day outlook of becoming colder.

I don't want to see charts like that verifying in early October!