The Influence of the Appalachian Mountains on the Precipitation Transition Zone

Winter storms in the eastern U.S. can significantly impact infrastructure and the economy. This work aims to develop a dataset of winter storms that impact the region directly west of the Appalachian Mountains from the Gulf Coast to the Great Lakes using the Weather Prediction Center’s Event Reviews. Analysis is performed on how conditions present in the Gulf of Mexico influence the position of the precipitation transition zone west of the Appalachians. Temperature, pressure, and vector winds are analyzed 24 hours before and after the onset of precipitation to track the storm system evolution. Integrated Water Vapor Transport (IVT) and Precipitable Water (PW) fields are examined to track the movement of moisture into the system from the Gulf of Mexico. Freezing precipitation is associated with the southward propagation of an Arctic anticyclone well ahead of precipitation, but the freezing precipitation is not prolonged directly west of the Appalachians due to the extent and magnitude of warm air surging northward from the Gulf of Mexico. The results are based on a relatively small sample size, and further research is planned. However, this work intends to help correct model biases and inform forecasters, in pattern recognition aid in predicting the evolution of the precipitation transition zone directly west of the Appalachian Mountains.