Observations of a Florida Waterspout during CaPE

Abstract

A case of a waterspout that developed from a relatively small cumulus cloud is presented. This is believed to be the first time that detailed Doppler radar information on a parent cloud has ever been collected. Vertical cross sections of radar reflectivity confirmed that the waterspout formed during the growth stage of the parent cloud and dissipated when a rain shower from a descending precipitation core reached the surface. Although the waterspout was as close as 15 km from the radar, a pronounced rotational couplet was not detected below 1 km MSL owing to the small width of the vortex. Surprisingly, the largest azimuthal shear within cloud in excess of 20 ? 10?3 s?1 was recorded as the waterspout dissipated. Results from past studies suggest that the vortex documented in this paper was typical of many waterspout events and, accordingly, may be difficult to resolve with the use of the new WSR-88D even at close ranges.