On 19/12/2016 18:01, Col wrote:
On 18/12/2016 19:40, Adam Lea wrote:
On 18/12/2016 18:22, Graham wrote:


:The SST anomalies still point to a preponderance of cyclonic westerlies
:for the UK so another mild winter seems most likely. The pattern
looks a
:bit more favourable for more meridional patterns than in recent years
:but a north-westerly reaching us from the East Greenland Sea would not
:be anywhere near as cold as it was fifty years ago when there was at
:least twice as much ice there as there is now.

I did say when Scott did his winter forecast on the 1st that I fancied
another mild or very mild December and looking at the charts see no
reason to change that view.
Despite a chilly night last night the mean still way up here at +2.6c
Yet another green Christmas, I wonder how many of them we've had in the
last 50 years


Graham


Well a green Christmas, at least for where most people live, is way more
likely climatologically than a white Christmas (even when they try to
make it as likely as possible by using the absurd requirement of a
single flake of snow to fall). The snowy landscapes on Christmas cards
go back to the little ice age when white Christmases and cold winters
would have been far more frequent. December 2010 and March 2013 are very
much the exception rather than the rule.

But isn't the single snowflake definition essentially that of a 'snow
day' which
is a standard meteorological obsevation? The only other way to do it
would be a day with snow lying, which would seem rather unfair if a
major blizzard set in at 10am.



Well if it were up to me, I'd class it as a white Christmas if there is
lying snow any time during the day, which seems to me to be the most
intuitive way of defining it, since the "white" part surely relates to
visual observation of the landscape. By this definition your 10am
blizzard would result in a white Christmas.

In message , Col
writes
On 19/12/2016 18:15, John Hall wrote:
In message , Col
writes
But isn't the single snowflake definition essentially that of a 'snow
day' which
is a standard meteorological obsevation? The only other way to do it
would be a day with snow lying, which would seem rather unfair if a
major blizzard set in at 10am.

I don't know see that as especially unfair. After all, with the single
snowflake definition, if it truly was just one (or even a handful) of
snowflakes, the observer might very well miss it. (I doubt that there's
any automated equipment capable of spotting a single snowflake.) Or you
could get a snow shower occurring a mile away from the met. station but
not at the station itself (or vice versa). The phrase "white Christmas"
makes much more sense if it refers to lying snow, and it's certainly how
I have always thought of it.

Unfair in the sense that it would miss the official definition of a
'snow lying day' if there was lying snow after the 9am observation time.


Yes, I know. But it doesn't seem any more unfair to me than the possible
unfairnesses with falling snow that I've outlined. And I like the
suggestion that's been made that lying snow at any time during the day
should count.
--
John Hall
"One can certainly imagine the myriad of uses
for a hand-held iguana maker"
Hobbes (the tiger, not the philosopher!)

Yes, I know. But it doesn't seem any more unfair to me than the possible
unfairnesses with falling snow that I've outlined. And I like the
suggestion that's been made that lying snow at any time during the day
should count.
I know where you are coming from John.
Out two Coldest December's (1981 & 2010) both had lots of lying snow and
were both ice days, yet they were not classed as a white Christmas.
1976 by comparison had a few light snow flurries and that was classed a
white Christmas, seems a bit bizarre.



Graham

Yes, I know. But it doesn't seem any more unfair to me than the possible
unfairnesses with falling snow that I've outlined. And I like the
suggestion that's been made that lying snow at any time during the day
should count.
I know where you are coming from John.
Out two Coldest December's (1981 & 2010) both had lots of lying snow and
were both ice days, yet they were not classed as a white Christmas.
1976 by comparison had a few light snow flurries and that was classed a
white Christmas, seems a bit bizarre.



Graham

In message , Graham
writes


Yes, I know. But it doesn't seem any more unfair to me than the
possible unfairnesses with falling snow that I've outlined. And I like
the suggestion that's been made that lying snow at any time during the
day should count.
I know where you are coming from John.
Out two Coldest December's (1981 & 2010) both had lots of lying snow
and were both ice days, yet they were not classed as a white Christmas.
1976 by comparison had a few light snow flurries and that was classed a
white Christmas, seems a bit bizarre.


I've been thinking about it, and I suspect that the bookies may prefer
to use "snow falling" rather than "snow lying" because it's less easy to
forecast a week or so in advance. In 2010, for instance, one could be
pretty sure a week in advance that much of the country would have snow
lying on Christmas Day. That would have meant that the bookies would
have had to set odds of something like 5-1 on, which in turn would have
meant that few people would want to bet and so the bookies' profits
would suffer.
--
John Hall
"One can certainly imagine the myriad of uses
for a hand-held iguana maker"
Hobbes (the tiger, not the philosopher!)