Mesoscale Weather Effects of Variable Snow Cover over Northeast Colorado

Abstract

Abstract Data from the PROFS (Program for Regional Observing and Forecasting Services) surface mesonetwork have been used to document the effect of variable snow cover on atmospheric boundary layer properties cloudiness and weather conditions over north Colorado on 15 April 1983. On this day an oval-shaped ∼104 km2 area of snow-free ground surrounded by snow-covered ground existed along the Colorado Front Range. While sky conditions on the morning of this day were everywhere clear, cloudiness developed by midday over the snow-free region as a result of the more rapid boundary-layer heating and mixed-layer growth there. During midafternoon snow showers occurred over the snow-free ground whereas sides remained mostly clear over the snow-covered area. Our analysis suggests that snow boundaries in the region may have acted through the development of a weak solenoidal field to enhance low-level inflow into the snow-free area, thereby assisting with cloud development in the region. Analogous to the sea bronze, ...