Quick check of how we are doing against that CET forecast a few days ago:
A calculation based on latest GFS 06z output (with a conservative estimate of nigh minima) suggests cumulative CET increasing as follows from today to the 31st:
17th 18.0; 18th 18.1, 19th 18.2, 20th 18.2, 21st 18.3, 22nd 18.5, 23rd 18.6, 24th 18.8, 25th 18.9, 26th 18.9, 27th 18.8, 28th 18.7, 29th 18.7, 30th 18.6, 31st 18.5
Up to the 21st we are at 18.5C per Met Office, 0.2 above what the model showed last week.
Today's GFS 06z output shows this going as follows:
22nd 18.6, 23rd 18.6, 24th 18.6, 25th 18.5, 26th 18.5, 27th 18.5, 28th 18.5, 29th 18.4, 30th 18.4, 31st 18.3
The number doesn't go as high last anticipated last week and that's largely because the real heat stays in the East. The CET is really affected by temperatures in the West of England because 3 of the 4 stations are West of Birmingham.
Brockley, South East London 30m asl