My recent mini-session with Alisha + Kih at Trowbridge Falls had about 3 different weather systems in the span of 30 minutes, but that made for an extremely fun and spontaneous session. It started with overcast skies, then quickly turned to large hail and eventually to clearing skies.
During that time, we managed to get a few keepers with smoke bombs, a titanic reenactment and some extremely fogged up glasses. All in all a very productively chaotic session.