Here is a summary of the NWP output for noon on Wednesday.
Issued 0550, 15th March 2008

The latter half of the working week will see a change to much colder
conditions over the UK, as low pressure moves SE'wards over the North Sea.
At this time of year, the flow is likely to be very unstable, with heavy
(and wintry) showers possible anywhere. Over the higher ground of the north
the showers are likely to fall as snow and there's a chance (albeit a much
lower one) of snow pretty much anywhere. Settling snow is unlikely away from
the north, however, due to the strength of the sun at this time of year.

Analysis and evolution to T+120 via GFS
http://85.214.49.20/pics/Rtavn001.png
SE'lies cover much of the UK, with low pressure to the SW. Tomorrow low
pressure moves over England and Wales, with strong NE'lies to the north. A
ridge moves in from the NW on Monday, leading to northerlies and NNW'lies.
Tuesday sees a ridge persist over the UK, with ENE'lies for England and
Wales and NW'lies elsewhere.

T+120 synopsis
http://85.214.49.20/pics/Rtavn12015.png /
http://85.214.49.20/pics/Rtavn1201.png
http://85.214.49.20/pics/Rukm1201.gif
http://85.214.49.20/pics/Recm1201.gif /
http://www.meteociel.fr/modeles/nogapse_cartes.php
The jetstream chart shows strong jet across the North Atlantic, with a large
blocking ridge to the west. At the 500hPa level there are strong NW'lies,
with a low to the NE. MetO has upper NNW'lies with a ridge to the west,
while ECM brings NNW'lies as well. GEM has upper westerlies with a weak
ridge aloft.
At the surface GFS brings strong WNW'lies, due to a deep low to the ENE of
Scotland. MetO has a ridge over the UK with westerlies and WSW'lies, while
ECM has a mix of NW'lies and WSW'lies, again with a weak ridge over the UK.
GEM shows a ridge as well, this time with westerlies and SW'lies.

Evolution to T+168
ECM brings low pressure east of Scotland on day 6, with strong WSW'lies and
WNW'lies. The low deepens to the east on day 7, leaving strong NNW'lies
across the UK.
A low lies to the east on day 6 with GFS, leading to NW'lies for all. On day
7 a low forms over Biscay, drawing NNE'lies over much of England and Wales.
Elsewhere winds are NNW'lies.

Looking further afield
Moderate northerlies cover the UK on day 8 with ECM, with low pressure to
the east and a large high to the west. There's little change on day 9, but
by day 10 a ridge moves in from the west, bringing westerlies to Scotland
and NNE'lies elsewhere.
Day 8 with GFS shows NW'lies with low pressure to the north and a ridge to
the west. On day 9 milder NW'lies cover the UK as a secondary low moves in
from the NW, followed by further NW'lies and WNW'lies on day 10 as the low
crosses Scotland.

Ensemble analysis
(http://91.121.94.83/modeles/gens/gra...ille=Lond res)
The ensembles show a couple of warm days aloft, followed by a prolonged cool
spell.

Darren Prescott wrote:

Here is a summary of the NWP output for noon on Wednesday.
Issued 0550, 15th March 2008

The latter half of the working week will see a change to much colder
conditions over the UK, as low pressure moves SE'wards over the North
Sea. At this time of year, the flow is likely to be very unstable,
with heavy (and wintry) showers possible anywhere. Over the higher
ground of the north the showers are likely to fall as snow and
there's a chance (albeit a much lower one) of snow pretty much
anywhere. Settling snow is unlikely away from the north, however, due
to the strength of the sun at this time of year.

Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman
--
Norman Lynagh
Chalfont St Giles, Buckinghamshire
85m a.s.l.
(remove "thisbit" twice to e-mail)

Norman wrote:
Darren Prescott wrote:

Here is a summary of the NWP output for noon on Wednesday.
Issued 0550, 15th March 2008

The latter half of the working week will see a change to much colder
conditions over the UK, as low pressure moves SE'wards over the North
Sea. At this time of year, the flow is likely to be very unstable,
with heavy (and wintry) showers possible anywhere. Over the higher
ground of the north the showers are likely to fall as snow and
there's a chance (albeit a much lower one) of snow pretty much
anywhere. Settling snow is unlikely away from the north, however, due
to the strength of the sun at this time of year.

Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman

11 April 1978 [about 0800]

10.0 cm at Hornchurch.
OS TQ 5386

Similar at Bedford too.

================================================== ========

" The bottom! "

Mike Hatton wrote:



Norman wrote:
Darren Prescott wrote:

Here is a summary of the NWP output for noon on Wednesday.
Issued 0550, 15th March 2008

The latter half of the working week will see a change to much colder
conditions over the UK, as low pressure moves SE'wards over the North
Sea. At this time of year, the flow is likely to be very unstable,
with heavy (and wintry) showers possible anywhere. Over the higher
ground of the north the showers are likely to fall as snow and
there's a chance (albeit a much lower one) of snow pretty much
anywhere. Settling snow is unlikely away from the north, however, due
to the strength of the sun at this time of year.

Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman

11 April 1978 [about 0800]

10.0 cm at Hornchurch.
OS TQ 5386

Similar at Bedford too.

I think the point that Darren was making about snow not settling due to the
strength of the sun was because we're dealing with showers here and the sun
will quickly heat surfaces and prevent snow settling. In situations where
snow is prolonged, and occurs before the sun has warmed the ground, snow
has been seen to settle as late as June (2/6/1975 in East Anglia).

I remember one lunchtime spent in a pub one March (how unusual!) when we had
frequent snow showers but when I went to my car (oh dear!) I had to leave
the doors open to let the oven-like interior cool off before I got in.

--
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]

On Sat, 15 Mar 2008 09:35:38 GMT, Norman wrote in


Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman, it could well have been 1981 when many places had prolonged snow,
enough to close a few airports for a time.

--
Mike Tullett - Coleraine 55.13°N 6.69°W posted 15/03/2008 12:26:29 GMT

"Mike Tullett" wrote in message
...
On Sat, 15 Mar 2008 09:35:38 GMT, Norman wrote in


Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman, it could well have been 1981 when many places had prolonged snow,
enough to close a few airports for a time.

--
Mike Tullett - Coleraine 55.13°N 6.69°W posted 15/03/2008 12:26:29 GMT

I recall the event in April 1978, living in Tooting at the time and came in
during the early evening, IIRC.


--
David Mitchell, 70m amsl, Langtoft, East Riding of Yorkshire.

"Mike Tullett" wrote in message
...
On Sat, 15 Mar 2008 09:35:38 GMT, Norman wrote in


Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman, it could well have been 1981 when many places had prolonged snow,
enough to close a few airports for a time.

Late April 1981, 23rd-25th something like that.
There was 6 inches of snow in north Leeds, of the wet variety.
I always remember the weight of it brought down large branches
of a tree we had in the front garden that was pretty much in leaf.

I don't know if it's my memory playing tricks on me but I
remember warm & sunny weather (20C+) ocurring just
the week before.

1981 was a good year for winter weather.
After the April event we had the amazing December.

They don't make 'em like that anymore!
--
Col

Bolton, Lancashire
160m asl

"Col" wrote in message
...

"Mike Tullett" wrote in message
...
On Sat, 15 Mar 2008 09:35:38 GMT, Norman wrote in


Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman, it could well have been 1981 when many places had prolonged snow,
enough to close a few airports for a time.

Late April 1981, 23rd-25th something like that.
There was 6 inches of snow in north Leeds, of the wet variety.
I always remember the weight of it brought down large branches
of a tree we had in the front garden that was pretty much in leaf.

I don't know if it's my memory playing tricks on me but I
remember warm & sunny weather (20C+) ocurring just
the week before.

1981 was a good year for winter weather.
After the April event we had the amazing December.

They don't make 'em like that anymore!
--
Col

Bolton, Lancashire
160m asl

Not that I was living there at the time, but I lived next to the Scout Hut
in Penistone which collapsed under the weight of snow in the 81 event and
over a foot fell. It was rather fortunate, as the next day a visiting troupe
were due to stay the night there.
In Cornwall we had wet snow that didn't settle, but I visited Wiltshire a
couple of days after and there was still a lot of snow around on the downs.
The oil seed rape was looking in a right state, having been in full flower
before the snow.

--
David Mitchell, 70m amsl, Langtoft, East Riding of Yorkshire.

Graham P Davis wrote:

Mike Hatton wrote:



Norman wrote:
Darren Prescott wrote:

Here is a summary of the NWP output for noon on Wednesday.
Issued 0550, 15th March 2008

The latter half of the working week will see a change to much
colder conditions over the UK, as low pressure moves SE'wards
over the North Sea. At this time of year, the flow is likely to
be very unstable, with heavy (and wintry) showers possible
anywhere. Over the higher ground of the north the showers are
likely to fall as snow and there's a chance (albeit a much lower
one) of snow pretty much anywhere. Settling snow is unlikely away
from the north, however, due to the strength of the sun at this
time of year.
Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to
mind was on or about 20th April in, I think, the late 1970's when
there was an accumulation of 2-3 inches even in Central London

Norman

11 April 1978 [about 0800]

10.0 cm at Hornchurch.
OS TQ 5386

Similar at Bedford too.

I think the point that Darren was making about snow not settling due
to the strength of the sun was because we're dealing with showers
here and the sun will quickly heat surfaces and prevent snow
settling. In situations where snow is prolonged, and occurs before
the sun has warmed the ground, snow has been seen to settle as late
as June (2/6/1975 in East Anglia).


If I remember correctly, the 1978 event resulted from a line of showers
that moved south across SE England during the evening, a couple of
hours after sunset.

Norman
--
Norman Lynagh
Chalfont St Giles, Buckinghamshire
85m a.s.l.
(remove "thisbit" twice to e-mail)

On 15 Mar, 12:26, Mike Tullett wrote:
On Sat, 15 Mar 2008 09:35:38 GMT, Norman wrote in


Though there have been many notable cases at this time of year and
later with heavy accumulations after dark. One that springs to mind was
on or about 20th April in, I think, the late 1970's when there was an
accumulation of 2-3 inches even in Central London

Norman, it could well have been 1981 when many places had prolonged snow,
enough to close a few airports for a time.

--
Mike Tullett - Coleraine 55.13°N 6.69°W *posted 15/03/2008 12:26:29 *GMT

I was in Wootton Bassett near Swindon in late April 1981 and there was
3-4" of snow. I seemed to remember it snowed heavily for several
hours. There was no power and we had to boil water for coffee on a
camping stove in the garage.

Graham
Penzance