Miserlou
With +20C on the ground and the very far from reliable tops forecast on F215 forecasting tops at 10k ft, this means one is very likely to get freezing before one climbs on top. Even the usually useless 2C/1000ft formula says it will be 0C at 10k ft.
The only time I would regard a tops forecast as reliable is
a) when I look up and from the holes showing blue sky above it is obvious the layer is some 2000ft thick (and with a de-iced prop I would fairly happily climb through that even if it was all freezing), or
b) I can get a Skew-T from e.g.
http://weather.uwyo.edu/upperair/sounding.html
(choose region=europe and type of plot = GIF/skew-t) and a nearby station shows (in a very recent ascent) something like this
http://weather.uwyo.edu/cgi-bin/soun...400&STNM=03354
which shows a well defined top at about 1500m. This is in effect a METAR.
Otherwise, a 10k ft top forecast could be anywhere from say 5000ft to 15000ft. The great thing about F215 weather is like ISO or BS Standards - there are so many to choose from
