I am in the sub tropics so a thunderstorm is an afternoon certainty for about 6
months of the year. The only question is whether it will come over you. The
local weather RADAR on cable TV is the best forecaster. I certainly wish
someone would bvroadcast that on an unused UHF channel!!! Then a $69 TV would
be your weather station.
As it is we make do by watching the strato cumulous formations and plotting
them against a fixed object to determine the direction of travel. The sun is
handy for this when you are out in the middle of nowhere.