A couple of GFS runs last night had the N Scandinavian/Russian High
building South Westwards by the coming weekend with ridging into the
the UK High which weakened. The effect was an Easterly regime which
quickly dragged in cold continental air even at 850 hPa, this was down
to -10 deg C across most of England within a day or two.

I didn't post at the time as I expected it to disappear by today and
it has (maybe it was an outlier) but it does show the possibility of
sharp forecast changes even at 5 days out. This was no T+360 fantasy -
even though it may turn out to have been a half day wonder.

I'll believe such charts when I see the forecast conditions actually
happen - but we don't need to give up just yet, chaps. Not for another
couple of weeks, anyway!

--
Dave