Is there a ceiling on weather patterns?
Severe convection will have anvil tops at the tropopause and overshooting tops can penetrate much higher (severe thunderstorm warnings often use a value of 60,000 ft for threats to aircraft).  How high the overshooting tops can get is a balance of the positive buoyancy during parcel ascent against the negative buoyancy once it gets into the warming stratospheric air.  

A U2 could overfly these storms, but most aircraft are not designed for stratospheric flight (due to the temperature increasing with height in the stratosphere) and any commercial aircraft will be unable to go over these storms.