Impact of Downscaling on Forcing Engine for Operational Water Prediction System of National Water Center

This study investigated the impacts of downscaling on the meteorological forcing for the NOAA National Water Model (NWM). The system uses real-time, operational forcing from the NOAA/ESRL High Resolution Rapid Refresh (HRRR) output, and NOAA/ESRL Rapid Refresh (RAP) model results to drive the analysis and short-range forecasting. The NCEP Global Forecast System (GFS) output is used to construct the forcing for the medium range (0-10 day) forecasts, and the NOAA Climate Forecast System (CFS) provides the forcing for the long range (0-30 day) forecasts. Meteorological input data are regridded to a common 1-km CONUS domain and selected variables (temperature, humidity, pressure and shortwave radiation) are topographically downscaled to drive the the community WRF-Hydro model. The influences of downscaling on different type/resolution meteorological forcing for different forecast under different seasons are studied. The forcing from current downscaling method is also compared with the results from dynamic downscaling and downscaling analysis. The results are summarized in the presentation.