Wednesday, 17 January 2007: 4:00 PM
Relationships between tropical cyclones and heavy precipitation in the Carolinas
206A (Henry B. Gonzalez Convention Center)
There is a strong association between heavy rainfall and tropical cyclones in the Carolina region of the southeastern U.S. It is estimated that half of the wettest tropical cyclone events over the last 55 years have occurred during the last 10 of those years. In this study, cooperative observer reports across a region encompassing North and South Carolina are scanned between 1950 and 2003 and used to construct a 54 year time series of precipitation events. Mean areal precipitation totals are estimated across four sub-regions (Mountains, Western and Eastern Piedmont, and Coastal Plain) for each event identified in the time series. Estimates of the contribution of tropical cyclones to events of different intensities (e.g. 1, 5, 10 year storms) are computed for each sub-region. The precipitation totals in each region are related to various aspects of the tropical cyclone (speed of movement, size, and strength) as well as the relative position and strength of various synoptic features surrounding the tropical system (e.g. location of fronts, region upper level divergence and high water vapor contents in the atmosphere). Map composites are constructed to illustrate the weather features that most distinguish tropical cyclones that produce ordinary versus extraordinary precipitation totals.