The familiar sight of the westerlies roaring in from the Atlantic in early
December again this year is an early hint of the weather pattern that is
likely to prevail later in the winter ...... but it's early days! I have
long believed that the ' crunch' time comes soon after the middle of the
month. If a spell of arctic weather develops at that time, even if it lasts
only a few days,then the chances of a major cold spell after Christmas are
much higher. If you look at the coldest winters since the end of WW 2,
nearly all of them gave a hint of things to come in the weeks leading up to
Christmas. I can think of the Decembers of 1946, 1955, 1962, 1968, 1969,
1978,in 1984 and 1985 the cold spell arrived at Christmas, 1986, and 1990.
The late Colin Finch devised a sort of clue that if, in his part of Surrey,
the temperature failed to reach 38f ( 3.5c) on 4 consecutive days in
December up to Christmas then a cold late-winter was highly likely. If this
clue proved negative( ie no cold spell) a mild winter was almost certain -
this is certainly upheld by events in recent years.

A recent example of Colin's clue came in December 1996 when a cold east wind
spell
developed just before Christmas and January 1997 turned out to be a cold
month. In 2000 the cold weather arrived
at Christmas and January turned out to be a chilly month - by the standards
of recent years.

So many recent years have given what I call a ' phantom cold spell' in mid
December.
.. A high settles over the country in early/ mid December but the air is not
particularly
cold. With clear skies on some nights there are frosts and some fog, but
day temperatures are unremarkable unless the fog lasts all day - as last
year. Then, after a few days, the high moves
away and the westerlies return.

Of course, all these weather theories are fallible, but it's interesting to
speculate and
it will be interesting to see, this year, whether the westerlies suffer a
serious interruption before Christmas.

Peter Clarke
Ewell, Epsom

Peter Clarke wrote:
The familiar sight of the westerlies roaring in from the Atlantic in early
December again this year is an early hint of the weather pattern that is
likely to prevail later in the winter ...... but it's early days! I have
long believed that the ' crunch' time comes soon after the middle of the
month. If a spell of arctic weather develops at that time, even if it lasts
only a few days,then the chances of a major cold spell after Christmas are
much higher. If you look at the coldest winters since the end of WW 2,
nearly all of them gave a hint of things to come in the weeks leading up to
Christmas. I can think of the Decembers of 1946, 1955, 1962, 1968, 1969,
1978,in 1984 and 1985 the cold spell arrived at Christmas, 1986, and 1990.
The late Colin Finch devised a sort of clue that if, in his part of Surrey,
the temperature failed to reach 38f ( 3.5c) on 4 consecutive days in
December up to Christmas then a cold late-winter was highly likely. If this
clue proved negative( ie no cold spell) a mild winter was almost certain -
this is certainly upheld by events in recent years.

A recent example of Colin's clue came in December 1996 when a cold east wind
spell
developed just before Christmas and January 1997 turned out to be a cold
month. In 2000 the cold weather arrived
at Christmas and January turned out to be a chilly month - by the standards
of recent years.

So many recent years have given what I call a ' phantom cold spell' in mid
December.
. A high settles over the country in early/ mid December but the air is not
particularly
cold. With clear skies on some nights there are frosts and some fog, but
day temperatures are unremarkable unless the fog lasts all day - as last
year. Then, after a few days, the high moves
away and the westerlies return.

Of course, all these weather theories are fallible, but it's interesting to
speculate and
it will be interesting to see, this year, whether the westerlies suffer a
serious interruption before Christmas.

Peter Clarke
Ewell, Epsom





Thanks for that Peter, very interesting, I see some truth in that as well.

http://85.214.49.20/wz/pics/Recm1681.gif

Mmm?
--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net

If December 2006 is anything to go by:

Date Mn Mx
20 -2.2 4.5
21 -3.2 3.2
22 -0.9 2.9
23 -0.4 3.5
24 3.0 4.5
25 4.5 5.7
26 3.4 5.0
27 3.0 9.7
28 7.2 10.5
29 7.2 12.5
30 7.2 12.5
31 7.7 11.9

The 'cold' spell from the 20th - 26th was the coldest of the entire winter.
The temperatures from the 29th onwards were more typical of the rest of the
winter. So who knows!

The outlaws are arriving from Portugal for Xmas. They always expect to see a
bit of snow but every year the weather fails and all they get is weather
very similar to what they are used to in Lisbon at Xmas: mild, wet, very wet
or torrential.
________________
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk

Nick,

Bring them up to Haytor.
5 cm snow lying on Xmas Day 2004 up here! Best white Christmas I have ever had,
sledging in the dark after lunch :-)
Even if there is no snow it is often much colder and more seasonal.

Will
--

"Nick Gardner" wrote in message
...
If December 2006 is anything to go by:

Date Mn Mx
20 -2.2 4.5
21 -3.2 3.2
22 -0.9 2.9
23 -0.4 3.5
24 3.0 4.5
25 4.5 5.7
26 3.4 5.0
27 3.0 9.7
28 7.2 10.5
29 7.2 12.5
30 7.2 12.5
31 7.7 11.9

The 'cold' spell from the 20th - 26th was the coldest of the entire winter.
The temperatures from the 29th onwards were more typical of the rest of the
winter. So who knows!

The outlaws are arriving from Portugal for Xmas. They always expect to see a
bit of snow but every year the weather fails and all they get is weather
very similar to what they are used to in Lisbon at Xmas: mild, wet, very wet
or torrential.
________________
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk

Peter Clarke wrote:

The familiar sight of the westerlies roaring in from the Atlantic in
early
December again this year is an early hint of the weather pattern that
is
likely to prevail later in the winter ...... but it's early days! I have
long believed that the ' crunch' time comes soon after the middle of the
month. If a spell of arctic weather develops at that time, even if it
lasts
only a few days,then the chances of a major cold spell after Christmas
are much higher. If you look at the coldest winters since the end of WW 2,
nearly all of them gave a hint of things to come in the weeks leading up
to Christmas. I can think of the Decembers of 1946, 1955, 1962, 1968,
1969, 1978,in 1984 and 1985 the cold spell arrived at Christmas, 1986, and
1990.

I don't know about the other years you mentioned but 1962 had cold spells
well before "the" cold spell started. For one week in November at Bedford,
the temperature failed to get above zero. Also, in December, there was a
spell of freezing fog with a fall of ice needles from it. Snow fell at
times during both months.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman, not newsboy.
"What use is happiness? It can't buy you money." [Chic Murray, 1919-85]

"Nick Gardner" wrote in message
...
If December 2006 is anything to go by:

Date Mn Mx
20 -2.2 4.5
21 -3.2 3.2
22 -0.9 2.9
23 -0.4 3.5
24 3.0 4.5
25 4.5 5.7
26 3.4 5.0
27 3.0 9.7
28 7.2 10.5
29 7.2 12.5
30 7.2 12.5
31 7.7 11.9

The 'cold' spell from the 20th - 26th was the coldest of the entire
winter. The temperatures from the 29th onwards were more typical of the
rest of the winter. So who knows!


________________
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk

Thanks Keith and Nick for your comments; the point I was making about
December last year was that, on the 19th, a High moved up from the
south-west and settled over the country for a few days, but it did not
introduce arctic/ continental air and there wasn't any snow. With clear
skies at night and near enough to the shortest days, there was some frost
and fog, of course. A typical ' phantom cold spell'.

Peter Clarke