Sounds like you know what you are doing so this is just brief:
The only product I know of which offers in-flight weather radar is this one
http://www.moving-terrain.de/index_de.htm
which has a very substantial entry cost.
Otherwise there are some weather radar websites, best is the last one
http://www.buienradar.nl/home.aspx?r...soort=loop1uur
http://www.chmi.cz/OPERA/ (used to have weathr radar links but they have just been removed)
http://www.eumetnet.eu.org/
http://www.meteox.com/h.aspx?r=.pete...soort=loop1uur
Then there are "stormscope" sites, such as
http://www.blitzortung.de/index.php?mode=6&map=3&lang=e (download the java viewer)
http://www.sv2bzq.gr/hystory_weather/stormvue.html
and many more.
A stormscope (I have a wx500) will show nothing unless there are discharges. So a CU/TCU is unlikely to show unless it gets going properly.
It's best to use a website like
http://pages.unibas.ch/geo/mcr/3d/meteo/ (animated soundings)
to get an idea of forecast cloud tops and then file a flight plan above that. On the day, get the SigWX which indicates more cloud top data and indicates areas with vertical development. Plus TAFs, METARs etc all along the route which should show really dodgy stuff.
Obviously you need oxygen
