On Tue, 15 Sep 2009, Richard Dixon wrote
On 15 Sep, 20:11, Nick wrote:

Seems to have been much worse in the central south (I'm in
Southampton) than the southeast. Mostly light but seemed almost
torrential for a short while around 6.30pm. I have to admit I'm amazed
at how active this system, which just seemed to be a minor trough on
the south side of the high, has been.

Given the linear nature of the rainfall, I am beginning to suspect
some of my favourite - conditional symmetric instability - might be at
play. Basically the sort of instability you get at thunderstorms but
along frontal surfaces that organises rainfall in narrow, intense
bands - however the alignment of the jet and the local temperature
gradient suggests that it might not be the case.

Certainly I can't remember a day since working in the City where I've
seen such heavy rain throughout the day. Surprised Clerkenwell was
only showing 15mm as per Phil's email just now.

Richard

Went to an open-air performance of the Yeomen of the Guard at the Tower
of London last night. Had to beat a retreat at the interval because
even the supplied plastic poncho with several layers underneath couldn't
cope with the downpours, which came in massive pulses (you kept thinking
it was all over). Perhaps if I'd had windscreen wipers on my specs....

--
Kate B

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