Brings to mind a rather hair-raising experience I had in 2003 on a Bangkok Airways ATR 72 departing Hua Hin on a stormy night. At what I would estimate to have been no more than 100 feet agl there was a pronounced loss of lift, as if someone had just pushed the aircraft down out of the sky. Windshear/Microburst? - I don't know I'm no expert, but we lost at least half of the altitude we had gained. Even now I have a vivid mental picture of the startled faces of people in cars passing by on the road running past the end of the runway. There was no increase in power, as I guess we were at full take off power anyway, and just as soon as it had begun it was over and the aircraft then climbed away as normal. Nothing at all from the cockpit, so I still don't really know what happened but certainly wouldn't like to experience it again.