Radar analysis of deep convection in landfalling tropical cyclone rainbands: tornadic and nontornadic cells
Heather B. Anderson, University of North Carolina, Charlotte, NC; and M. D. Eastin
Landfalling tropical cyclones and their associated hazards pose a continuous threat to coastal communities during the late summer and early autumn. One such hazard is tornadoes that are often spawned by convective cells in the outer rainbands. These tornadic cells, while similar in some ways, are often considerably different in size, structure, longevity, and intensity than their Great Plains counterparts due to their immersion within the dynamic tropical cyclone (TC) environment. These differences pose a great challenge to forecasters attempting to distinguish between the tornadic and nortonadic cells as a given TC moves onshore. The focus of this study is to identify and document defining radar-derived characteristics of tornadic and nontornadic convective cells embedded within outer TC rainbands in an effort to improve tornado genesis prediction and forewarning.
The primary data source used in this study is the NEXRAD Level-II data obtained by the Jacksonville, Tallahassee, Charleston, Columbia, and Wilmington WSR-88D radars on 26-27 September 2004 as Hurricane Jeanne made landfall and moved northeast through the Carolinas. The GR2Analyst software is used to examine the radar data. A number of both tornadic and nontornadic cells are identified and tracked as they move onshore. Radar-derived characteristics such as maximum reflectivity, echo top altitude, vertically integrated liquid and rotational velocity are determined and tabulated for each volume scan. Nearby rawindsonde and dropsonde observations are used to characterize the stability and vertical shear profile of each cell's local environment. A synopsis of our results and their comparison with previous studies will be presented at the conference.
Poster Session 1, Student Conference General Poster Session
Sunday, 20 January 2008, 5:30 PM-7:00 PM, Exhibit Hall B
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