STORM TRACK: July 31, 1980 (Volume 3 Issue 5)

Lt. Curtis photographed a large waterspout for over forty minutes last winter, from shipboard, 2-5 miles away. The structure was a classic double core funnel with an unusual bonus -something Jan calls the "sliding knot" effect. Over a period of 4-12 seconds each, several bulges -or knots- were observed moving down the vortex core from cloud to water level, moving slowly at first and then accelerating downward.

"I've noticed nearly every single very dark isolated CB has some form of funnel associated with it. In the tropics, the maximum likelihood for such an occurrence would be at, sunrise, around noon and 2 hours before sunset. It appears to form not out of downdraft but out of rapid evaporation from the wall cloud. Virga with s twist.."

P.S. Jan will be moving to the Washington, D.C. area this October for a tour of duty.