On Saturday, July 14, 2018 at 4:03:59 PM UTC+1, Graham Easterling wrote:
After a calm, sunny start Cu very quickly developed over the land and by 10:30 there was a F3 sea breeze. By 11:00 there was some quite threatening cloud along the sa breeze convergence zone, this was pushed over Penzance around 11:30 as the north coast sea breeze became the dominant one. Just ahead of it the sea breeze became a F4 briefly. Around noon, after the blast of ‘sea’ air and the southward passage of a band of threatening cloud, the temperature was around 20C.

Then the cloud got pushed away to the south a dissipated, the wind varied form calm to F1-2 offshore, and the temperature shot up. now 24.5C under strong sunshine.

This was a fairly common sea breeze sequence, the south coast one dominant in the morning, the north coast in the afternoon. The first day that it looked like we might get a shower for quite a while. Places on the north coast have had virtually unbroken sunshine.

Graham
Penzance

The well defined convergence zone can be seen on these sat pics from Bernards site
NOON
http://www.woksat.info/etcaag14m/aag14-msg-1200-uk.html
Particularly narrow & well defined in west Cornwall.
By 15:00
http://www.woksat.info/etcaag14m/aag14-msg-1500-uk.html
It had been pushed south by the north coast sea breeze, now offshore (west of St Austell) and largely dissipated (as had the sea breeze in Penzance) with the exception of a patch left just east of the Lizard.

24.5C turned out to be the maximum.

Graham
Penzance