September CET!

[J10]

Just before the deadline 14.8c

[Calrissian]

Calrissian: September - 14.5 :huh:

[Polar Continental]

Oops, I missed the dead line, 13c if allowed.

Paul

[Optimus Prime]

Latest GFS run indicated the period 1st-5th will have an average temperature of 15.2c. 0.3c above average for the first half of September.

[summer blizzard]

13C: Fishdude

13.2C: Beng

13.3C: Eddie

13.3C: Noggin

13.6C: Memories of 63

13.7C: Snow-Man2006

13.7C: Norrance

13.8C: Rollo

13.8C: Tribe3000

13.9C: Snowyowl9

13.9C: Sundog

13.9C: DamianSlaw

13.9C: Blast From The Past

13.9C: Dancc

14C: Steve B

14C: Anti-Mild

14C: Phil n.works.

14.1C: The PIT

14.1C: The Eye In The Sky

14.1C: Tamara G

14.1C: Ned

14.1C: Glacier Point

14.2C: Gavin P

14.2C: Mr Maunder

14.2C: Mega Moon Flake

14.2C: Stu London

14.2C: Terminal Moriane

14.3C: Geordie Snow

14.3C: Steven Prudence

14.3C: Stargazer

14.3C: Osmposm

14.4C: Mr Data

14.4C: Atlantic Flamethrower

14.4C: Slipknot Sam

14.4C: Joneseye

14.5C: Summer Blizzard

14.5C: Ghrud

14.5C: Kold Weather

14.5C: Dr Hosking

14.5C: Cheeky Monkey

14.5C: Calrissian

14.6C: Bottesford

14.6C: Snowray

14.6C: Magpie

14.6C: Mark H

14.6C: Vizzy2004

14.7C: Don

14.7C: Storm Chaser 1

14.7C: Catch My Drift

14.7C: UK Moose

14.7C: Windswept

14.7C: JohnAcc

14.8C: Snowhope

14.8C: Great Plum

14.8C: Somerset Squall

14.8C: Jackone

14.9C: Osbourne One-Nil

14.9C: Mammatus

15C: Cymru

15C: Acbrixton

15.1C: Shuggee

15.1C: Smith25

15.2C: Snowmaiden

15.2C: Stratos Ferric

15.2C: Village Plank

15.3C: Kentish Man

15.3C: Thundery Wintry Showers

15.4C: West Is Best

15.4C: Snowingman

15.5C: Optimus Prime

15.5C: Duncan McAlister

15.8C: Rodger J Smith

15.9C: Reef

17C: Craig Evans

13C: Paul Carfoot - 1 day late

[mk13]

I realise that that there will be a penalty for being late (away on business), but my punt for Sepember is 13.7C!

[Mark Bayley]

Back off holiday now from nerja. Very nice and hot. Sorry i am late but i will predict 13.6c

[summer blizzard]

http://www.climate-uk.com/

Phillip Eden has the CET for the first two days of September at 15.8C...

[Duncan McAlister]

Should fall in the morning and be significantly lower on Wednesday morning thanks to tonight's low minima. The higher predictions like mine aren't looking so good now, but I still think it'll end up above average.

As I predicted we've already had a dose of 0C 850 air, last September the 0C isotherm never reached our shores at all.

Edited September 3, 2007 by Duncan McAlister

[summer blizzard]

Personally i think that Snowingmans prediction of 15.4C is the upper limit, minima looks too cool in the early stages of the month to provide a big enougth rise to offset cooling airmasses during the month, i still would'nt rule out any of the lower predictions, given that the coolest is only 0.7C below average.

[The Calm before the Storm]

Just got back from holiday from the Costa Blanca (unusually cool and unsettled incidentally) so apologies for missing the deadline (and yes I know there will be penalties!) but I'm going to plump for 14.0c. A warmish first half followed by an average to cool second half.

[Stu_London]

From www.climate-uk.com

CET 01-03 September 15.2C

This is actually 0.1C below average for this time of the month, which demonstrates how quickly the mean starts to drop away at this time.

Cool or cold in some places this morning. We will probably drop to mid 14s in the next day or so then stablise for a period.

Ensembles have more or less done away with the retrogression and back door northerly and there is a trend for warmer conditions around mid month. However mid-September 10C 850hpas are very different to high summer. Expect 25C at a push for maximas.

[North-Easterly Blast]

Looks like the modern post 1997 UK climate is showing its ugly faces again, with the GFS and most other models showing warm high pressure glued slap bang over the UK until this time next week at least, and the next seven days' forecast is warm. We just do not seem to be able to achieve a CET below 14*C in September any more, and we have not had a wetter than average September since 2000. September has become one of the main months of the year to be affected by UK Climate Change over the last ten years, and warm high pressure has just become the default September setting.

We have cracked one trend this year, and August has finally broken the trend of recent years of never being able to record a CET below 16*C, and September just needs to buck the trend.

A return to cooler and wetter Septembers will more than likely lead to a switch back to a climatological pattern that leads to colder winters. As long as Septembers continue warm and dry like recent years it is difficult to see a cold winter in the UK, or the winter patterns to deverge away from the patterns of recent winters.

[Stratos Ferric]

...

A return to cooler and wetter Septembers will more than likely lead to a switch back to a climatological pattern that leads to colder winters. As long as Septembers continue warm and dry like recent years it is difficult to see a cold winter in the UK, or the winter patterns to deverge away from the patterns of recent winters.

You might like to account for the "more than likely" point of view. There is absolutely no link whatsoever that I can see between the behaviour of any one specific month and any other, save for that that would normally be expected by the progression of the seasons.

It may well be that September will cool down, relatively, in coming years, but it is no less likely that other months will warm up by comparison. Indeed, IF a warming climate is accepted then this would HAVE to happen (averaged over time).

From www.climate-uk.com

CET 01-03 September 15.2C

...

Cool or cold in some places this morning. We will probably drop to mid 14s in the next day or so then stablise for a period.

...

Unless you're redefining stablise Stu, to mean "upward movement less stark than some we have seen in recent years" I very much doubt we'll be staying on the level. Daily averages around 16 look more than likely for 4-5 days from tomorrow / Thursday.

[Kentish Man]

Looks like the modern post 1997 UK climate is showing its ugly faces again, with the GFS and most other models showing warm high pressure glued slap bang over the UK until this time next week at least, and the next seven days' forecast is warm. We just do not seem to be able to achieve a CET below 14*C in September any more, and we have not had a wetter than average September since 2000. September has become one of the main months of the year to be affected by UK Climate Change over the last ten years, and warm high pressure has just become the default September setting.

We have cracked one trend this year, and August has finally broken the trend of recent years of never being able to record a CET below 16*C, and September just needs to buck the trend.

A return to cooler and wetter Septembers will more than likely lead to a switch back to a climatological pattern that leads to colder winters. As long as Septembers continue warm and dry like recent years it is difficult to see a cold winter in the UK, or the winter patterns to deverge away from the patterns of recent winters.

Well personally I'm quite happy to have some prolonged warm dry weather after a poor summer by any standards. To me the climate has simply reverted back to normal variability after a freakish warm period culminating in this year's extraordinary April. Others have already demonstrated there is no connection between a warm September or October and the following winter. In any case it is far too early to identify this as a warm month - a chilly final 10 days could hammer the CET quite dramatically.

[Cymru]

If it stayed like this, or warmer, throughout September I would be happy. Time enough for Autumnal weather in October and November. Let's enjoy the sun and the warmth while we can. Remember it's a long time till next summer

[Stu_London]

Unless you're redefining stablise Stu, to mean "upward movement less stark than some we have seen in recent years" I very much doubt we'll be staying on the level. Daily averages around 16 look more than likely for 4-5 days from tomorrow / Thursday.

I have to accept the output has warmed up a bit during the course of the day. I guess we could end up around 16C average by the 10th - a bit a cooldown likely after that date.

[Stratos Ferric]

I have to accept the output has warmed up a bit during the course of the day. I guess we could end up around 16C average by the 10th - a bit a cooldown likely after that date.

To be honest Stu I'd have said the same thing based on Saturday's charts. Didn't see this morning's so I guess there might have been some subtle relocation of the HP, but the general trend for the next few days has always been 'returning' mT air; mild and likely cloudy at times, but with the potential to burn off during the day.

Yes, medium term looks like it might include a polar burst, but here and now we have a good run of high probability warmth, followed by a low probability (as all LRFs are) of something cooler. It's a while since we've had three cold months on the bounce and I still expect the majority of this month to stay settled.

Things MIGHT start to get more interesting synoptically next month if this general pattern continues.

[Don]

To be honest Stu I'd have said the same thing based on Saturday's charts. Didn't see this morning's so I guess there might have been some subtle relocation of the HP, but the general trend for the next few days has always been 'returning' mT air; mild and likely cloudy at times, but with the potential to burn off during the day.

Yes, medium term looks like it might include a polar burst, but here and now we have a good run of high probability warmth, followed by a low probability (as all LRFs are) of something cooler. It's a while since we've had three cold months on the bounce and I still expect the majority of this month to stay settled.

Things MIGHT start to get more interesting synoptically next month if this general pattern continues.

Well after two cooler than average months, we're now well over due a warmer than average month!

[Gavin P]

Well, I don't agree with North_Easterly_Blast that a warm and dry September automatically means that you throw in the towel for the coming winter, but I have to say, whats going on in September through the last few years is most extrodinary and without any precedent that I can find. People say that all months are random, and you can't pick out trends for one month based on a previous month, but as far as September goes, I'll say that it is beginning to become obvious that some freakish, cyclical pattern is at work. Look through the Wetter-Zentrale charts, and you see that relatively few Septembers actually start off with big, hot high pressure systems lasting for weeks and weeks on end. I would say that on average, up until 1997, it probably happens about once a decade. Then we come to the mid 90's and suddenly it starts happening year after year after year. And the weird thing is, it doesn't matter what pattern precede's September, through the summer months. We've had poor summers like 2002, 2005 and now 2007 lead to this freakishly anyticyclonic dominated pattern. We've had reasonable summers like 1997 and 1999 lead to freakishly hot/anticyclonic Septembers. And we've had really hot summers, like 2003 and 2006 lead to freakishly hot/anticyclonic Septembers. Its almost like we're caught in a never-ending cycle here, where variability has completely and totally gone out of the window, for just this one month of the year. Its like clock-work.... Its strange, freakish and weird, warming trend and all....

Edited September 4, 2007 by Gavin P

[Don]

Well, I don't agree with North_Easterly_Blast that a warm and dry September automatically means that you throw in the towel for the coming winter, but I have to say, whats going on in September through the last few years is most extrodinary and without any precedent that I can find. People say that all months are random, and you can't pick out trends for one month based on a previous month, but as far as September goes, I'll say that it is beginning to become obvious that some freakish, cyclical pattern is at work. Look through the Wetter-Zentrale charts, and you see that relatively few Septembers actually start off with big, hot high pressure systems lasting for weeks and weeks on end. I would say that on average, up until 1997, it probably happens about once a decade. Then we come to the mid 90's and suddenly it starts happening year after year after year. And the weird thing is, it doesn't matter what pattern precede's September, through the summer months. We've had poor summers like 2002, 2005 and now 2007 lead to this freakishly anyticyclonic dominated pattern. We've had reasonable summers like 1997 and 1999 lead to freakishly hot/anticyclonic Septembers. And we've had really hot summers, like 2003 and 2006 lead to freakishly hot/anticyclonic Septembers. Its almost like we're caught in a never-ending cycle here, where variability has completely and totally gone out of the window, for just this one month of the year. Its like clock-work.... Its strange, freakish and weird, warming trend and all....

Yes it is rather strange. It seems that in the last ten years the only September's not to follow this trend are 2000 and 2001.

[Gavin P]

Even 2001 was pretty anticyclonic. Its just that the anticyclone sat about 300 miles further west than we normally see (in the post 97 pattern) whoch meant winds were generally from a northerly point. But it certainly wasn't the wet, zonal September in the mould of 93, 94 or 95, etc.... As you rightly say, the only one of those typically wet Septembers was in 2000.

[summer blizzard]

Have any of you people actually checked the statistics regarding September...

Yes, September 2006 was the hottest on record, continuing the run of warm Septembers since 1997 aside from 2001...

http://www.metoffice.gov.uk/research/hadle.../HadCET_act.txt

However, September 2006 was certainly not anticyclonic...

http://www.climate-uk.com/monpre/0609.htm

Nor was it dry, it featured over 100mm of rainfall...

In regards to the warm Seotember theory, i don't buy it, from the reasearch i have done, it is November and December which are the important months in relation to the coming winter in my opinion, and ideally i would like to see both of those, cold and wet.

Edited September 4, 2007 by summer blizzard

[Gavin P]

By dry/wet, I'm talking essentially about about flow patterns. September 2006 was wet in some places, mainly because of torrential downpoars and thunderstorms. So, OK, it was a wettish month, yet synoptically it couldn't be more differant than say September 1995.

[snowray]

Well Summer this year has been in spring and most probably autumn too, could end up well above average. I wonder how long the big fat high (not lady singing )will hang around .....Jan/feb any one?? I knew the mid month Nleys would disapear they always do when they turn up this far out, though for the 1st time in my life I dreamt of heavy snowfall around here, could this be an omen, god I'm getting as bad a psychic Chris!