Numerical Weather Prediction Analysis of Cold Air Damming in the Mid-Atlantic Region
Eric Allen, University of Delaware, College of Earth, Ocean, and Environment, Newark, DE
Andrew Snyder, National Weather Service, Baltimore/Washington Weather Forecast Office
Michael Muccilli, National Weather Service, Baltimore/Washington Weather Forecast Office
Matthew Elliott, National Weather Service, Baltimore/Washington Weather Forecast Office
Howard Silverman, National Weather Service, Baltimore/Washington Weather Forecast Office

Abstract
Warm frontal passage throughout the Mid-Atlantic region is often complicated by terrain effects attributed to the Appalachian Mountains (e.g., cold air damming-CAD). Numerical weather prediction (NWP) guidance handling of the evolution/dissipation of CAD represents a challenge for forecasters. Situations of CAD-like behavior often occur with retreating Arctic air masses ahead of and/or with the onset of southerly or southwesterly flow in the boundary layer (below 850 hPa). Near surface dense cold air often takes longer to mix out in areas in which southerly flow is blocked by relatively higher terrain to the north/west. These events often have implications on high impact weather, such as occurrence of freezing rain and low cloud ceilings that affect aviation operations. NWP guidance during CAD situations will be evaluated for several cases in the Mid-Atlantic region. Parameters examined will include temperature, moisture, surface visibility and ceiling. This study will help identify which models handle CAD evolution/dissipation. Surface and upper air observations and geographical features will be analyzed to determine environments which are conducive to keeping cold air trapped near the surface.