Abstract:
Tropical cyclones pose a variety of weather hazards such as damaging
winds, storm surge, heavy rainfall and tornadoes. Numerous studies
have noted that tornadoes associated with tropical cyclones are
short-lived and are typically weaker than those associated with
extra-tropical cyclones.
Mesocyclone signatures associated with individual tornadic storms tend to be weaker, more shallow, have smaller diameters and are of shorter duration than mesocyclones in mid-latitude severe weather events. The shallow nature of Tropical Mesocyclone Signatures (TMS) has resulted in the failure of the WSR-88D mesocyclone detection algorithm (MDA) to identify a mesocyclone beyond 50nm from the Radar Data Acquisition (RDA) Site. The failure of the WSR-88D MDA to identify a mesocyclone increases the challenge in the warning decision process.
This paper will describe the characteristics of mesocyclone signatures associated with confirmed tornadoes which occurred over eastern Virginia and the Lower Maryland Eastern Shore during the passage of during the passage of Tropical Storm Bertha in July 1996 and Tropical Storm Danny in July 1997. The characteristics of the tornadic Tropical Mesocyclone Signatures (TMS) will summarized in an attempt to develop a strategy for warning decision using the WSR-88D in severe weather events in association with tropical cyclones.