9308409 Marwitz Severe wintertime weather, such as freezing weather, aircraft icing conditions, can be life threatening and very disruptive to human activity. Using data from previously completed field programs and an advanced numerical mesoscale atmospheric model, the Principal Investigator will study a variety of hazardous winter weather phenomenon. A primary focus will be to investigate the existence and characteristics of large supercooled water drops which are believed to be a necessary condition for severe icing conditions for aircraft. Additionally, the Principal Investigator will study effects of the dynamics and kinematics of shear layers and their association with large drop regions in clouds and the meteorological characteristics of a severe freezing rain episode. Successful completion of this research will contribute to efforts for better forecasting of these severe winter weather events. ***