Estimation of soil moisture gradients during Hurricane Fran (1996) and their influence on enhanced convection inland

The devastating damage associated with the passing of Hurricane Floyd (1999) and Fran (1996) have left a lasting mark on portions of the U.S. East Coast in their path. Local circulations often play a major role in enhanced convection after the hurricane makes land fall. This is particularly true for Hurricane Fran. It is believed that the development of the squall line and associated strong winds in Hurricane Fran were caused by local circulations resulting from large heat flux gradients induced by surface moisture gradients.

For this study, a heuristic model to determine soil wetness has been developed. This model is first initialized using climatological data. Soil wetness is estimated using values of air temperature, relative humidity and precipitation. In this study, the model will be applied to give estimates of the soil wetness values in eastern North Carolina during the progression of Hurricane Fran. The values of soil wetness calculated by the model will be used to estimate the surface sensible heat fluxes and then analyzed to study the observed enhanced convection associated with the hurricane.