Tuesday 13th March 2012


Meteosat MSG satellite picture from Ferdinand Valk's site at 12.00 UTC
http://www.fvalk.com/images/Day_image/MSG-1200-EUR.jpg

Meteosat MSG-2 satellite picture from Bernard Burton's site at 12.00 UTC
http://www.woksat.info/etcuc13m/uc13-msg-1200-uk.html

NOAA 19 satellite picture from Bernard Burton's site at 12.30 UTC
http://www.woksat.info/etcuc13/uc13-1230-b-uk.html


UK min. temps on Monday night http://tinyurl.com/6svkqel

Nottingham (Watnall) and Larkhill 3.1°C, Aviemore 3.0°C, Sennybridge
2.6°C, Boscombe Down 2.5°C, Glen Ogle 2.4°C, Dunkeswell and Lyneham
2.3°C, Farnborough 2.1°C, Tulloch Bridge 1.5°C, Pershore 1.3°C, Benson
0.9°C.

Altnaharra and Tiree 7.6°C, St Mary's (Scilly) 7.7°C, St Angelo, Aultbea,
Stornoway and Ronaldsway 7.8°C.


UK max. temps on Tuesday http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C, Fylingdales, Waddington
and Portland 7.2°C.

Chivenor 11.8°C, Kinloss and Leuchars 11.9°C, London St James's Park
12.0°C, Wick and Strathallan 12.1°C, Charlwood 12.2°C, Lossiemouth
12.5°C, Tain Range 12.7°C, Sennybridge and Liscombe 13.0°C, Aboyne
13.3°C.

OGIMET summary http://tinyurl.com/78wny38


Rainfall radar http://www.meteox.com/h.aspx?r=&soort=loop24uur&URL or
http://www.raintoday.co.uk/

Rainfall totals in 24 hours ending 18.00 UTC on Tuesday
http://tinyurl.com/832sc9k

Aberporth 0.6 mm, Stornoway and Lusa (Skye) 0.8 mm, Lerwick and Plymouth
(Mountbatten) 1 mm, Baltasound 2 mm.


Location of some UK stations
http://www.metoffice.gov.uk/educatio...eather-data-uk


Colin Youngs
Brussels

In article ,
Colin Youngs writes:
UK max. temps on Tuesday http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C, Fylingdales, Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

"John Hall" schreef

: Colin Youngs writes:
: UK max. temps on Tuesday http://tinyurl.com/826vk5a
: Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C, Fylingdales,
Waddington
: and Portland 7.2°C.

: That Portland temperature is a surprise. If correct, it suggests that
: the water of the English Channel must still be pretty chilly.

Seems to have been foggy all day
http://www.metoffice.gov.uk/weather/...er_graphs.html

Colin Youngs
Brussels

On Mar 13, 9:58*pm, John Hall wrote:
In article ,
*Colin Youngs writes:

UK max. temps on Tuesday *http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, *Spadeadam 6.9°C, *Bingley 7.1°C, *Fylingdales, Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.
--
John Hall
* * * * * * *"The power of accurate observation is commonly called cynicism
* * * * * * * by those who have not got it."
* * * * * * * * * * * * * * * * * * * * * * * George Bernard Shaw

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones today http://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

Anyone who's been out in a small boat in early Spring knows just how
cold it is just offshore!

Graham
Penzance (SST here around 10C, but during sea fog yesterday morning
the air temperatures was around 7.5C)

In article
,
Graham Easterling writes:
On Mar 13, 9:58*pm, John Hall wrote:
In article ,
*Colin Youngs writes:

UK max. temps on Tuesday *http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, *Spadeadam 6.9°C, *Bingley 7.1°C, *Fylingdales, Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones today http://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

That surprises me, as I thought that the mechanism for the formation of
sea fog was the sea cooling the air to its dewpoint. For the sea to cool
the air, the SST would surely have to be lower than that of the air? I'm
clearly missing something, as the measured temperatures can't lie.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

On Mar 14, 9:05*pm, John Hall wrote:
In article
,
*Graham Easterling writes:









On Mar 13, 9:58*pm, John Hall wrote:
In article ,
*Colin Youngs writes:

UK max. temps on Tuesday *http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, *Spadeadam 6.9°C, *Bingley 7.1°C, *Fylingdales, Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones todayhttp://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

That surprises me, as I thought that the mechanism for the formation of
sea fog was the sea cooling the air to its dewpoint. For the sea to cool
the air, the SST would surely have to be lower than that of the air? I'm
clearly missing something, as the measured temperatures can't lie.
--
John Hall
* * * * * * *"The power of accurate observation is commonly called cynicism
* * * * * * * by those who have not got it."
* * * * * * * * * * * * * * * * * * * * * * * George Bernard Shaw

I've never had it explained to me convincingly, but it is a fact. I
assume that under normal conditions, evaporation of the sea surface
lowers the air temperature just above. With sea fog, the sun is
commonly visible just through it, if not it's vertical extent is still
normally very limited. Perhaps evaporation from the top of the fog
bank cools it?

Any explanations welcome. Most reports from buoys show the SST above
the air temperature around 95% of the time, throughout the year.

Graham
Penzance

"Graham Easterling" wrote in message
...
On Mar 14, 9:05 pm, John Hall wrote:
In article
,
Graham Easterling writes:
On Mar 13, 9:58 pm, John Hall wrote:
In article ,
Colin Youngs writes:

UK max. temps on Tuesday http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C, Fylingdales,
Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones todayhttp://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

That surprises me, as I thought that the mechanism for the formation of
sea fog was the sea cooling the air to its dewpoint. For the sea to cool
the air, the SST would surely have to be lower than that of the air? I'm
clearly missing something, as the measured temperatures can't lie.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

I've never had it explained to me convincingly, but it is a fact. I
assume that under normal conditions, evaporation of the sea surface
lowers the air temperature just above. With sea fog, the sun is
commonly visible just through it, if not it's vertical extent is still
normally very limited. Perhaps evaporation from the top of the fog
bank cools it?

Any explanations welcome. Most reports from buoys show the SST above
the air temperature around 95% of the time, throughout the year.

Graham
Penzance
=======================

It is complex. As the fog forms an isothermal layer is set up within it at
around the skin SST. As it deepens and ages radiation from the fog top
lowers the temperature and also as you say insolation would cause
evaporation adding to cooling as well. In time this generates a weakly
convective over-turning within the bank, this mixes the air which will be
then cooler than the SST. This process can continue as the the SST itself
will then supply a heat source to drive the convective over-turning more
efficiently. So I think the main mechanisms are long wave radiative cooling,
evaporation at fog top and convective over-turning.

Cheers,

Will
--

In article ,
Dartmoor Will writes:

"Graham Easterling" wrote in message

groups.com...
On Mar 14, 9:05 pm, John Hall wrote:
In article
,
Graham Easterling writes:
On Mar 13, 9:58 pm, John Hall wrote:
In article ,
Colin Youngs writes:

UK max. temps on Tuesday http://tinyurl.com/826vk5a

Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C,
Fylingdales, Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones todayhttp://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

That surprises me, as I thought that the mechanism for the formation of
sea fog was the sea cooling the air to its dewpoint. For the sea to cool
the air, the SST would surely have to be lower than that of the air? I'm
clearly missing something, as the measured temperatures can't lie.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

I've never had it explained to me convincingly, but it is a fact. I
assume that under normal conditions, evaporation of the sea surface
lowers the air temperature just above. With sea fog, the sun is
commonly visible just through it, if not it's vertical extent is still
normally very limited. Perhaps evaporation from the top of the fog
bank cools it?

Any explanations welcome. Most reports from buoys show the SST above
the air temperature around 95% of the time, throughout the year.

Graham
Penzance
=======================

It is complex. As the fog forms an isothermal layer is set up within
it at around the skin SST. As it deepens and ages radiation from
the fog top lowers the temperature and also as you say insolation
would cause evaporation adding to cooling as well. In time this
generates a weakly convective over-turning within the bank, this
mixes the air which will be then cooler than the SST. This process
can continue as the the SST itself will then supply a heat source to
drive the convective over-turning more efficiently. So I think the
main mechanisms are long wave radiative cooling, evaporation at
fog top and convective over-turning.

Cheers,

Will
--



Thanks, Graham and Will.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

On Mar 15, 9:21*am, "Dartmoor Will" wrote:
"Graham Easterling" wrote in message

...
On Mar 14, 9:05 pm, John Hall wrote:









In article
,
Graham Easterling writes:
On Mar 13, 9:58 pm, John Hall wrote:
In article ,
Colin Youngs writes:

UK max. temps on Tuesdayhttp://tinyurl.com/826vk5a

Glen Ogle 6.5°C, Spadeadam 6.9°C, Bingley 7.1°C, Fylingdales,
Waddington
and Portland 7.2°C.

That Portland temperature is a surprise. If correct, it suggests that
the water of the English Channel must still be pretty chilly.

9 - 9.5C SST in that area. However, I've noticed that during sea fog,
the air temperature is typically around 2C below that of the nearby
SST.

Over open sea the air temperature is normally lower than the SST . See
Sevenstones todayhttp://www.ndbc.noaa.gov/station_page.php?station=62107
No sea fog, but air temperature below SST as normal. Under sea fog
conditions this phenomena moves over the coast.

That surprises me, as I thought that the mechanism for the formation of
sea fog was the sea cooling the air to its dewpoint. For the sea to cool
the air, the SST would surely have to be lower than that of the air? I'm
clearly missing something, as the measured temperatures can't lie.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw

I've never had it explained to me convincingly, but it is a fact. I
assume that under normal conditions, evaporation of the sea surface
lowers the air temperature just above. With sea fog, the sun is
commonly visible just through it, if not it's vertical extent is still
normally very limited. Perhaps evaporation from the top of the fog
bank cools it?

Any explanations welcome. *Most reports from buoys show the SST above
the air temperature around 95% of the time, throughout the year.

Graham
Penzance
=======================

It is complex. As the fog forms an isothermal layer is set up within it at
around the skin SST. As it deepens and ages radiation from the fog top
lowers the temperature and also as you say insolation would cause
evaporation adding to cooling as well. In time this generates a weakly
convective over-turning within the bank, this mixes the air which will be
then cooler than the SST. This process can continue as the the SST itself
will then supply a heat source to drive the convective over-turning more
efficiently. So I think the main mechanisms are long wave radiative cooling,
evaporation at fog top and convective over-turning.

Cheers,

Will
--

Thanks, that process may well help explain why virtually calm
conditions often exist within the fog bank, with breezier conditions
on it's edge.

Graham