FORECASTING AFTERNOON MIXING DEPTHS AND TRANSPORT WIND SPEEDS

Abstract

A method is presented to estimate the vertical extent of atmospheric mixing during the afternoon and the average transport wind speed, i.e., the average wind speed within the mixing layer. Afternoon mixing depth is assumed to be dependent upon the observed difference between the maximum afternoon surface temperature and the mean virtual temperature of the standard atmospheric layer containing the top of the mixing depth. Transport wind speed is assumed to be a function of the wind speed at the level nearest the center of the mixing depth. Based on special forecast material prepared by the National Meteorological Center, procedures are outlined for forecasting afternoon mixing depths and transport wind speeds.