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Global Warming
28 August 2015 21:35:25

August has been another rather disappointing month. There was some reasonable weather in the south for a while but the latter part of the month has been poor in most places. Temperatures are likely to end up a little below average. As we move into September will the Atlantic cold pool keep the below average conditions going? I strongly favour that outcome as things stand. 


Please post your September CET predictions in this thread. The deadline for entries without incurring any penalty is 23:59 on Monday evening (31st). However, entries will be accepted up to 23:59 on 2 September (Wednesday).


September historic data summary
Here is the usual rundown of historic data for previous years.


Apart from 2012 we have not seen a cool September since 1994. There have been plenty of very warm Septembers. 2012 saw a CET of 13.0C and 1994 was 12.7C. Between 1998 and 2006 the CET was 14.3C or above in all years apart from one.


Long run averages:
1971-2000: 13.7C
1981-2010: 14.0C
1995-2014: 14.4C


Here is a chart of the September CET since 1961 with a 10 year moving average



Current model output


The current model output suggests the whole of the first part of August could be fairly close to average overall. Contingency planners forecast is very interesting though and I would agree entirely with what is said.


GEFS
http://www.wetterzentrale.de/pics/MT8_London_ens.png
http://www.wetterzentrale.de/pics/MT2_London_ens.png

http://www.wetterzentrale.de/pics/MT2_Manchester_ens.png

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


Coolish start but returning close to average.


Met Office Contingency planners forecast
http://www.metoffice.gov.uk/media/pdf/0/a/A3_plots-temp-SON.pdf
Suggests an equally likely probability of cool or warm temperatures. No strong signal at all for September. A significant El Nino event often points to a warm September but the cool Atlantic SST's means that if winds come regularly from that direction the SSTs are likely to temper the normally warmer maritime conditions.


ECM - De Bilt
http://www.knmi.nl/exp/pluim/kansverwachtingen_staafdiagram.php?run=00&type=tx
http://www.knmi.nl/exp/pluim/kansverwachtingen_staafdiagram.php?run=00&type=tn


Very much on the cool side


Pattern matching (just for fun)
I had a quick look at the historic data with similar CET figures to the individual summer months from this year. Overall there is no obvious pattern to report. So nothing


September CET tracker
Here are the current prediction charts for the first part of September. Looking very chilly indeed I'm afraid. Well below the seasonal average. Maybe temperatures returning close to average by around the 9th but that is a long way off.


ARTzeman
28 August 2015 21:44:05

For myself I am going for 15.2c.  Thank you for the  Watch.…






Some people walk in the rain.
Others just get wet.
I Just Blow my horn or trumpet
redmoons
29 August 2015 00:34:02
I will go for a just below average month with the temperature picking up after a cool start.
13.2c
Andrew,
Watford
ASL 35m
http://weather.andrewlalchan.co.uk 





Dougie
29 August 2015 06:00:46

14.1°c please.


Ha'way the lads
roger63
29 August 2015 07:20:41

14.15C please.

Chunky Pea
29 August 2015 08:41:02

14.9 please.


Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Charmhills
29 August 2015 10:35:40

13.9c please.


Loughborough, EM.

Knowledge is power, ignorance is weakness.

Duane.
ozone_aurora
29 August 2015 11:31:15

I'll go for 14.8 C, please. A cool start but warming up later, and a mostly dry, settled month I think.

Easterly Beasterly
29 August 2015 12:12:43
13.8c please
Surrey John
29 August 2015 13:16:23
I'm taking a punt on a colder than average month at 12.8c

Thanks
Bradford on Avon, Wiltshire
35m ASL
Gavin P
29 August 2015 18:18:25

Think I'll go for 12.9 - Coldest since 1994 - Thanks GW! 


Rural West Northants 120m asl
Short, medium and long range weather forecast videos @ https://www.youtube.com/user/GavsWeatherVids
yorkshirelad89
29 August 2015 18:45:33

One thing I have noticed in recent months is that Atlantic cold pool shifting eastwards. I expect it to have a strong influence during Autumn. A higher incidence of northerly and north-westerly winds then average. Cool SSTs will probably favour colder minima.


A cool but dry September - 12.8C


Hull
Grandad
29 August 2015 20:31:33

Lots of cold expected by our forecasters.

Think I'll have to join them, but not so extreme - 13.6C please. .
domma
29 August 2015 21:06:01

14.4c for me , thanks


___________________________________________________________________________________________________________________


Gary

Hippydave
29 August 2015 22:48:17

13.9c for me please.


Home: Tunbridge Wells
Work: Tonbridge
wallaw
30 August 2015 05:27:36
14.7 for me please
Ian


Stockton-on-Tees

Hungry Tiger
30 August 2015 10:15:51

I'll go for


13.8C


 


Gavin S. FRmetS.
TWO Moderator.
Contact the TWO team - [email protected]
South Cambridgeshire. 93 metres or 302.25 feet ASL.


toasty
30 August 2015 11:26:51

14.2 please

Snow Hoper
30 August 2015 13:07:19

13.67C for me please 


Going to war over religion is like killing each other to see who has the better imaginary friend.


Home : Thorndon, Suffolk.
kendalian
30 August 2015 13:48:31

13.7C for me please....

springsunshine
30 August 2015 14:49:45

As gw points out the last cold September was over 20 years ago!


A significantly below average September and indeed autumn as a whole is way way overdue and given how this year has been on the chilly side im going to go for.......12.7c

Ally Pally Snowman
30 August 2015 17:08:54

A cold one I think with a persistent northerly. 11.9c please


 


 


 


Bishop's Stortford 85m ASL.
Stormchaser
30 August 2015 17:23:00

Shock horror - out of pure interest, I just did a CET estimate based on the GFS 12z op run, and by 6th September the anomaly is -3.9*C. Not only that but it barely recovers to the end of higher-res, sitting at -3.5*C up to 9th of the month.


A warmer lower-res then raises the anomaly somewhat, but by the end of the run - the mid-point of the month - the anomaly is still down at -2.2*C.


Even if the rest of the month was then equal to the LTA, the final anomaly would be near -1.0*C. So a pretty remarkable signal from GFS, and ECM has been looking very similar!


If you have any problems or queries relating to TWO you can Email [email protected]

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2023's Homeland Extremes:
T-Max: 30.2°C 9th Sep (...!) | T-Min: -7.1°C 22nd & 23rd Jan | Wettest Day: 25.9mm 2nd Nov | Ice Days: 1 (2nd Dec -1.3°C in freezing fog)
Keep Calm and Forecast On
rickm
31 August 2015 00:27:56

14.0 for me this month please


 

Whether Idle
31 August 2015 07:12:22

14.0 please


Dover, 5m asl. Half a mile from the south coast.

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