I turned my easel to face northward along the Southampton shore. A quasi-stationary front stretching west to east across the tip of the Bruce Peninsula was a focus for several thunderstorms. This particular thunderstorm developed an overshooting top as I painted. It collapsed about an hour later and got lost in the haze over the horizon. The lowering evident in the painting was possibly a shelf cloud from the forward flank rain and downdraft. There was no evidence of any rotation in the lowering or cell although it was a long way to the north and tough to identify even under ideal conditions.This is the fifth demo piece for the “Making Waves on Chantry” course. The artists were on lunch break and I decided to paint a meteorological lesson and not waste any time. The onshore wind blew some (lots of) sand into the paint. We have an excellent group of 11 participants!