Stratus Surge Prediction along the Central California Coast

Abstract

A simple decision-tree forecast scheme to predict the south-north development or movement of stratus along the central California coast is developed and tested. Known as ?stratus surges,? these mesoscale events are infrequently observed along the west coast of North America during the summer season. A subjective test involving inspection of visible image satellite photographs is successful in determining when the potential for surge development exists. Objective tests based on Oakland, California, radiosonde data and alongshore pressure gradients at 0000 UTC are developed to make ?surge? and ?no surge? forecasts for potential events. Skill scores show that forecasts based on the objective tests achieved a moderate level of accuracy. This technique is easy to apply and could serve as a basis for the development of other stratus surge forecast schemes along the coast.