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.
Edited by moderator
11 October 2015 11:24:57
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Reason: Not specified