I don't think it was a cloud head at that time. There was a mass of convection
in the area which as the left exit of the powerful jet approached started to
become more organised due to mass ascent inucing a rotation as the PV max
interacted with the cloud area. At that time I could see a developing wave and
mass ascent taking place on the cold side of said wave. Buckling of the imagery
and more cloud top cooling will be a better sign of rapid deepening beginning.

Will.
--

"Martin Rowley" wrote in message
...
Martin Rowley wrote:
Embryonic cloud-head appearing in the cirrus shield just west of
Corunna -

http://makeashorterlink.com/?G4D32414E

"Waghorn" wrote
Captured in the Hi res vis at 15Z.
http://west-cheshire.ac.uk/weather/msghreuvis.asp
Not sure we are actually seeing the actual cloud head at this time,
but
we must be very close,

... yes difficult isn't it! Always much easier when it's all done and
dusted ;-)
It's got the 'look' of the early stages of such, and looking at the
sequence, the cooling tops are becoming more organised .... interesting
few hours coming up

Martin.