In message , Eskimo Will
writes

wrote in message
...
Having had a week of not so bitter weather with temps around 5C I was
expecting it to be colder today. So why, with 850 hPa indicating -8C
here, sub 528 dam, is it 6C and raining in the showers?


Long fetch off a super warm North Sea below 850 hPa melting the
snowflakes aloft. Sadly for you SE folk the days of sig. snow at low
level are getting rarer, unless the North Sea cools down more again in
winters, it will remain thus. At altitude, in places like Luton, snow
will continue to occur regularly but it will not be bitter. You are
quickly becoming like the south coast whereby the only time you will
get sig. snow is if the 1000-500 hPa thickness falls below 516 DAM, or
you get a more continental air fetch or a "special" synoptic setup like
a slow moving front with a fetch off colder land. Snow lovers need to
gain latitude or altitude, preferably both.

Though with an easterly the sea track will be very short, so we should
still get snow in those situations. However they've been very rare in
recent years.

Interestingly, we now seem to get more snow in Surrey than they do in
Essex, which never used to be the case. Presumably that's because the
sir that has been warmed close to the surface by crossing the North Sea
has had nore chance to cool down again.

Of course in prolonged cold spells, the North Sea will become colder and
SE England will get more snow, as illustrated in 2009-10 and December
2010. So I'm not that pessimistic.
--
I'm not paid to implement the recognition of irony.
(Taken, with the author's permission, from a LiveJournal post)