NWP Cloud Initialization Using GOES Sounder Data and Improved Modeling of Nonprecipitating Clouds

Abstract

Cloud-top pressures and effective cloud amounts, derived from Geostationary Operational Environmental Satellite (GOES) sounders, are used to specify a three-dimensional mesoscale cloud field for numerical weather prediction. A bulk cloud parameterization scheme based on relative humidity is introduced into the forecast model to efficiently use the satellite sounder observations. The cloud initialization and bulk cloud parameterization are tested in the Cooperative Institute for Meteorological Satellite Studies Regional Assimilation System for summer and winter periods. Comparisons between cloud forecasts and GOES cloud observations for four model configurations are presented. It is shown that the use of the initialization improved the areal coverage of the nonprecipitating clouds early in the forecast period, which translated to an improvement of the precipitation equitable threat score for the 24-h forecast (when the model initial time was 1200 UTC) and the 36-h forecast (when the model initial time was 0000 UTC).