"Will Hand" wrote in message
...
Darren, I think the western limb is only temporary, a surge of low
potential
vorticity (warm air) which will help to maintain the omega block in the UK
longitude. I
Thanks, Will - I'm still getting to grips with all this upper-air stuff,
having belatedly realised it's quite important regarding our weather!

ECMWF 12Z from www.ecmwf.int is consistent with its 00Z
predecessor maintaining the block more or less over the UK and then
retrogressing slightly at the new T+168 stage. If that trend is continued
then
we could be facing a cyclonic northeasterly in the extended outlook which
would
be fun! GFS consistent with UKMO. All going to plan so far.
Going by today's performance, GFS isn't even consistent with itself - a
stranded fish would do less flip-flopping! Over the past day the models seem
to have backed away from that Siberian easterly blast shown by the JMA, ECM
and GFS at various stages, but the latest scenario of high pressure parked
near the UK would still be pretty cold.

The ECM ensembles tonight point to a prolonged cold spell just to our east,
it seems that idea of an omega block near the UK is well supported:

http://www.ecmwf.int/products/d/samp...rope/page.html