Numerical simulation of a 4-day early spring storm period in the Black Hills

This paper illustrates the potential for mesoscale: models to depict the di stribution of precipitation in orographic situations. The study covers a 4- day time period in April 1995. The domain of the numerical model covers muc h of western South Dakota and some of eastern Wyoming and is centered on th e Black Hills of South Dakota. The 4-day storm period is characterized by c hanging atmospheric conditions, from primarily rain generation to snowfall production. Observations and climatic data of precipitation are analyzed to compare with model predictions. The model demonstrated the ability to resp ond appropriately to changing input conditions and produced reasonably accu rate simulations of observed precipitation patterns. The model performed we ll for sufficiently cold, strongly forced conditions but seemed overly sens itive to the accuracy of model assumptions regarding ice initiation for war mer, weakly forced situations.