Have you tried contacting the Met Office? They used to have a Meteorological Flt that used a C-130 although that has been replaced by a BAe-146
http://www.faam.ac.uk/
They would most likely have done the whole deliberate flying through storms thing rather than everyday sqn pilots who tend to like living and so avoid that sort of thing like the plague.
The USAF also has various met research ac, not sure of details at this late hour, but you could try them as well.