"Tom Bennett" wrote in
:

For the past 40 mins or so I've been watching a very large area of
cloud moving in here from the NE Very marked upward development and
streamers of white precipitation visible along the leading edge.

The cloud reminds me strongly of that of a large summer TStorm.

Just noticed on the 2pm radar quite a noticeable band coming into the
London area, stretching from S Kent northwards up through Suffolk (?) -
looks like it's developed quite a bit in the last hour. Maybe that's what
you're seeing now? It's definitely moving in a ENE-WSW direction.

Cheers
Richard