Noticed that the chart for yesterday midday showed a cold front over
the southern UK, yet maximum temperatures yesterday were about 5C
warmer than the last few days? Why was this classed a cold front when
it introduced warmer air? Temperatures were both warmer by day and much
warmer by night, so both surface and upper air appeared to be warmer.

Nick

wrote in message
oups.com...
Noticed that the chart for yesterday midday showed a cold front over
the southern UK, yet maximum temperatures yesterday were about 5C
warmer than the last few days? Why was this classed a cold front when
it introduced warmer air? Temperatures were both warmer by day and much
warmer by night, so both surface and upper air appeared to be warmer.

Nick

A front marks a strong wet-bulb potential temperature gradient, so very
roughly speaking what you say about surface and upper air tending to be
warmer holds.

However, think of the insolation factor over the last two days. Within the
cloud-ladened frontal boundary insolation was very slight, however here in
Manchester behind the cold front there was hardly a cloud in the sky to
inhibit the sun warming us up.

You don't give a location for the "5degC warmer than the last few days",
which is a bit general.

Joe
--
Withington, Manchester

I always think - doubtless far too casually - of a cold front as
meaning a change to lower dewpoints.

Jack

wrote in message
oups.com...
Noticed that the chart for yesterday midday showed a cold front over
the southern UK, yet maximum temperatures yesterday were about 5C
warmer than the last few days?
Nick


However, think of the insolation factor over the last two days. Within the
cloud-ladened frontal boundary insolation was very slight, however here in
Manchester behind the cold front there was hardly a cloud in the sky to
inhibit the sun warming us up.

You don't give a location for the "5degC warmer than the last few days",
which is a bit general.

Joe
--
Withington, Manchester


Maximum temperatures in Penzance 19.5 on 19th under cloud ahead of the
front, 20.1 on 20th in strong sunshine, so I wouldn't regard it as warmer.

The air under the front was certainly warm, giving a very muggy night
19th/20th but there was a slight drop in both temperature & humidity as the
front cleared Penzance around 09:00

Graham

Penzance Weather www.easterling.freeserve.co.uk/weather.html
Holiday Cottage www.easterling.freeserve.co.uk

wrote in message
ups.com...
I always think - doubtless far too casually - of a cold front as
meaning a change to lower dewpoints.

Jack

When I worked for Isles of Scilly Skybus, on many occasions we'd be in the
fog at Land's End airport desparately waiting for the cold front to go
through so that we could resume flights. It typically cleared on Scilly 1 -
2 hours before Land's End (about 35 miles).

Graham