Analysis of the Froude Number during a Cold Air Damming Scenario in the Appalachian Region

Cold Air Damming (CAD) can cause frozen precipitation events that can have serious implications on everyday mountain and transportation operations. SEAR-MAR, a National Science Foundation funded project, allowed for airborne research for a variety of atmospheric events. On Nov. 4, 2017, we collected data of a Cold Air Damming event in the Appalachian Mountains via the University of Wyoming King Air research aircraft along with windsonde observations. With the data collected, we calculated the observed Froude number; a dimensionless number that can relate to the intensity of a CAD scenario. Data collected was compared to the Weather Research and Forecast (WRF) computer model simulation data of the same event. Our goal is to analyze the Froude number for both WRF model and collected data and compare the two to see how accurate the WRF model is at forecasting CAD. After analyzing and comparing the WRF model with our data collected from the windsondes, it is clear the WRF model predicted a lower Froude number than observed. Our analysis suggested with a low Froude number bias, the WRF model overestimates the intensity of CAD. By better understanding intensity values of CAD, we may further research ways to improve model forecasts during these scenarios.