N Cornwall sea breeze thunderstorms.

[Graham Easterling]

So predictable, as soon as the sea breeze kicks in (often strong up the Camel estuary) then storms in the Padstow / Wadebridge / Camelford & (of course) Boscastle areas

15:20

16:25

It's always that part of the north Cornwall coast. I believe that Trevose Head and other headlands play a part, as headlands encourage 3 way convergence.

I really don't understand how the NT got away with filling the flood plain at Boscastle with tarmac after the last Boscastle flood, which they claimed was a 1 in 200 years event, when similar rainfall totals, & river levels just as high, occured twice in the 1950s. There have been many other rather more minor floods following severe storms in the Camelford Boscastle area in the last 100 years. Much of the structural damage done in the last flood was due to cars being washed out of the car park. 

Another excuse to link to http://penzanceweather.atwebpages.com/SrMerrynStorm.PDF

Graham

Penzance - (where it's been a lovely sunny afternoon once low cloud broke up during the morning. Medium Cu over the land, now starting to spread out. )

[Freddie]

With a little assistance from an upper trough too.  I don't think they would've developed without that additional dynamic uplift today.

[Graham Easterling]

Well yes, conditions have to be favourable, clearly, which they were today for a number of reasons.  But the final trigger was undoubtedly the sea breeze onset. Once the warning area was extended down the north coast it' was  possible to predict, based on previous events, the most likely spots for storms. That's what I meant by it being predictable.

I think the one storm in Cornwall which really came out of the blue, and am not sure if it's ever been that well explained, was the Coverack storm, which was incredibly localised, dropping >200mm in a very small area behind Coverack. There wasn't even a shower anywhere else remotely nearby, and certainly no warning in place, even as it was happening.. 

Graham

Penzance