6B.2
The overland reintensification of Hurricane Danny in July of 1997
PAPER WITHDRAWN
Chris Smallcomb, University of Wisconsin, Madison, WI; and M. C. Morgan
The only landfalling tropical cyclone of the 1997 Atlantic hurricane season, Hurricane Danny came ashore near Mobile, Alabama on 18 July as a minimal category one hurricane on the Saffir-Simpson Scale. After traversing the southeastern United States over the next three days the storm began to re-intensify as a tropical cyclone while over land in Virginia and North Carolina. The fact that Danny was in close proximity to a lower tropospheric frontal zone when it began to re-intensify suggests the importance of lower tropospheric baroclinicity in the redevelopment of the tropical cyclone.
This study uses observations including surface, upper-air, radar, and satellite data along with numerical model simulations employing the NCAR/PSU MM5 mesoscale model to diagnose the spin-up of the lower tropospheric vortex.
Results will show that Danny reintensified due to an interaction with a lower tropospheric thermal boundary over Virginia. In addition, the upper-tropospheric synoptic scale flow was found to be favorable for development of a low-level cyclone. Notably, an upper jet located to the northeast of the storm was established to be an outflow jet for the developing low-level disturbance enhancing upward vertical motions in the center of the cyclone. Danny displayed characteristics of a tropical cyclone including a troposphere-deep warm core during the reintensification phase.
Session 6B, Tropical cyclogenesis I (Parallel with Sessions 6A and J3)
Wednesday, 24 May 2000, 1:45 PM-2:45 PM
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