SYNOPTIC CLIMATOLOGY OF HEAVY SNOWFALL OVER THE CENTRAL AND EASTERN UNITED STATES

Abstract

Verification shows that recent guidance and official heavy snowfall forecasts have achieved only a modest degree of success. Therefore, the synoptic-climatological relationship of heavy snowfall to those, surface and upper-air features which are routinely forecast, is studied in an attempt to improve, operational forecasting of heavy snowfall east of the Rockies. The relationship is modeled in a way suitable for direct use on available circulation prognoses. The models relate percentage frequency of occurrence of heavy snowfall in 12-hr. periods to the initial 500-mb. absolute vorticity maximum, the 500-mb. height contours, the 1000?500-mb. thickness contours, and the surface low pressure center.