"Bernard Burton" wrote in message
...
Could it be, Dave, that the model data you quote is incorrect? The midday
ascents show 850 mbar temperature in the range -7 (Albermarle) to -9 (De
Bilt). The closest to your model value was Paris (-10), but the surface
temp
there is -3.
Another thing, if the lapse rate is equal to the dry adiabat, it indicates
a
well mixed layer, not the opposite. You can not have a shallow surface
layer
warmed by the underlying sea, with colder air above, and also have an
unmixed layer at the surface. When cold air overlies a warm sea, there is
a
flux of heat from the sea to the atmosphere, and this will lead to a well
mixed boundary layer up to where ever the capping inversion is. In today's
instance, using the ascent for Nottingham at midday, there is a dry lapse
rate up to about 950 mbar, then a saturated lapse up to a capping
inversion
at 800 mbar, T= -10. The layer surface to 800 mbar presents a well mixed
layer with convection up to 800 mbar.
The GFS vertical charts for Europe (1800z) do not show 850 mbar temps
anywhere near -11 between 49N and 69N on the Greenwich meridian.
http://www.wetter3.de/vertikal.html

Watch for the line wrap!
http://weather.uwyo.edu/cgi-bin/soun...F%3ASKEWT&YEAR
=2010&MONTH=02&FROM=1312&TO=1312&STNM=03354


-----------------------
Thanks for the info Bernard - but am I mis-reading these two charts then?
One is the GFS ensemble 850 hPa data for London and the other the GFS hi-res
850 hPa chart at 18z showing -10C and the earlier cold pool having passed
through earlier in the afternoon to the continent. This cold pool
corresponding to my 4C temp at 2pm. I'm clearly a bit confused!
http://www.wzkarten3.de/pics/MT8_London_ens.png
http://www.wzkarten3.de/pics/Rmgfs002.gif

Cheers,
Dave