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Old March 14th 12, 09:32 PM posted to uk.sci.weather
Graham Easterling[_3_] Graham Easterling[_3_] is offline
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Default Tuesday cooler than Monday - Aboyne 13.3°C highest

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