"Martin Rowley" wrote in message
...

"Joe Hunt" wrote in message
...

"Martin Rowley" wrote in
message
...
A very unstable looking sky from dawn to around 07Z, whence the
high-base CU (I did think AC, but looking at the ascent below), not
sure
I could justify AC), rapidly dispersed.
snip
Hi Martin,

It looks ominous on the latest visible imagery -
http://www.west-cheshire.ac.uk/weather/visible.htm

MetO F215 has Ac from 8000/20000 but only isolated in the S (more N.
France) and not really in your area. Maybe some convergence along the
SW
peninsula may push things later on, it's what the 15Z F215 is going
for
with a risk of a TS.

... whether connected with my early morning observation I'm not sure,
but we've just had (from 1715 to 1820Z) some very useful rain ....
1.3mm, with a 'moderate' burst near to the beginning of the event. The
sky looked very 'threatening' (Beaufort letter = 'u'), and it was so
dark for an hour before the rain set in that the local street lamp came
on. Reminded me a bit of the scene from the 'Darling Buds of May' ....
"Perfick".

Martin.

Hi Martin,

Going on from your earlier thoughts it seemed, from the 12Z Larkhill
ascent, that surface based convection caused Cu to grow into the base of
the Ac. Even the Cu tops would have been around MS08 degC. Ac is certainly
possible from the aforementioned ascent, unlike the one you depicted
earlier.

ATB, Joe (from a cool Manchester, where the top temperature was reached
around 17Z when the CUSC sheet dispersed slightly)