On Mar 12, 10:01*am, Scott W wrote:
The temperature on my AWS in Wanstead, east London, fell to a low of
2.7C at 0718z today, by 0738z it had risen to 4C. Is this normal for
the time of year? I would normally put it down to solar radiation but
there is thick low cloud here.
Also on the ride home from central London last night I noticed thick
patchy fog had formed over Wanstead Flats - quite unexpected from the
forecast - and the air also "felt" colder than I was expecting it to
be from the forecast.
My wife remarked that the air outside felt very "cold - colder than it
should do" as she walked the girls in this morning - anyone else
notice anything strange... Are these phenomena cause by us being slap
bang underneath a high pressure? It would be interesting to see how
low the usual frost hollows got last night - Chipstead Valley in
Surrey, Benson, Oxon etc

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A slight puff of wind would induce some mixing which might account for
the 20 minute temperature rise but a bit of incoming radiation
wouldn't hurt either.

Relatively moist air under high pressure in early spring with plenty
of overnight radiation = ideal conditions for stratus and fog (so I'm
not sure how unexpected it was - any forecast that didn't mention fog
was not a good one!)

I can't comment much on the physiological aspects (how cold it
"felt"). But Benson's minimum was +0.9, Farnborough's +0.6,
Charlwood's -0.1 and Chesham's -0.8. For comparison, High Wycombe's
minimum was +4.1 and Kenley's +4.7. Fog/low cloud formation prevented
greater falls in temperature, and it may develop earlier tonight so it
might be less cold.

Stephen.