Hi Clack100
Some other carriers have avoid by 10 miles below 10,000 and by 20 miles above 20,000. Still others have for every 10 knots of wind you must clear the tops by 1000'
A good piece of information by airbus can be found here.
http://www.airbus.com/fileadmin/medi...V_WX-SEQ07.pdf
My experience is to know the environment and weather attributes for the region I operate in. Even then to be cautious. Lots of advice out there but the best is
There is no reason to fly through a thunderstorm in peacetime. (Sign over squadron operations desk at Davis-Monthan AFB)