A Case for Detailed Surface Analysis

Abstract Detailed analysis of the temperature and moisture fields based on routine hourly surface observations in North America can provide a rational basis for surface feature analysis, thus clarifying the present confusion. Recognition of surface features is an important part of weather forecasting and is especially needed in a careful diagnosis for the prospects of deep convection. Surface temperature gradients are advocated as the primary basis for identifying fronts; examples are given of gross discrepancies in current operational practice between the surface temperature fields and the associated frontal analyses. Surface potential temperature, selected as a means of compensating for elevation differences, is analyzed in the western United States for a period in which a strong, damaging cold front develops and dissipates over a period of less than 24 h. Frontogenesis-related calculations, based on detailed surface temperature analyses, help to explain a case of focusing of heavy precipitation in nort...