wrote in message ...
| I recorded a low of 4.4c last night between 02.00 - 03.00
| yet Volmet S was giving for locations within 100 miles
| temps between 9 to 13c at same time .Anybody confirm/
| explain this diff' (sky was clear)

Hi John,

If you are in a slight hollow or valley and winds were calm it seems about right.
A situation occurs where a low level nocturnal inversion makes places around
you, who are at slightly higher altitudes, warmer.

Gatwick, at 196ft asl, last night went down to 7C, whereas Luton, at 526ft asl,
only went down to 11C. The 00z sounding from 03882 Herstmonceux shows
the very low level inversion being formed, bearing in mind at 05z-06z it would
be more pronounced -

http://makeashorterlink.com/?E273165C5

Here is the 06z 03743 Larkhill ascent showing 8.2C at 133m and 13.0C at 257m.
After this time insolation would warm the inversion out.

http://makeashorterlink.com/?C1A3345C5

HTH Joe

--
Wymeswold, NW Leicestershire, 83m asl
52° 48.47' North 1° 6.61' West
OS Grid - SK 59972 23779