Snow cover and its interaction with the earth's troposphere has become a topic of increased interest over the past several decades. Studies have produced evidence of links between snow cover and precipitation patterns, temperature fields, and atmospheric circulation patterns. Few studies have investigated anomalous atmospheric temperature and circulation patterns over snow cover boundaries or patchy snow cover. This study provides analysis of model-derived lower atmospheric temperatures and contributing energy fluxes within a cold air mass positioned over discontinuous snow cover. Results of the analysis show that simulated air mass temperatures were 1--4 ¿C cooler over a patch of snow cover than over surrounding bare ground during a midday hour. The temperature differences were primarily the result of variations in the magnitude and direction of the surface layer sensible heat flux, as produced by differences between the solar radiation absorbed by the snow cover and the surrounding bare ground. ¿ 1998 American Geophysical Union