Evaluation of NDFD and downscaled NCEP forecasts in the Intermountain West

As part of a larger project to improve hydrological forecasting in snow-melt dominated basins, we have implemented a method to downscale 14-day meteorological forecasts to the locations of snowpack telemetry (SNOTEL) stations in the Intermountain West (Idaho and northwestern Montana). We use historical meteorological records from the SNOTEL sites, along with the forecasting archive from NCEP's Experimental week 2 forecast product (1979–2001), to develop MOS-based regression equations for downscaling. This method is similar to the technique recently introduced by Clark and Hay using cooperative (COOP) meteorological stations across the U.S. along with NCEP's MRF model results. Using the MOS-based regressions, we have forecasted temperature at the SNOTEL sites throughout a recent snow-melt season (April-July 2005). We have also acquired the 7-day forecasts from the new National Digital Forecast Database (NDFD) for this time period at the SNOTEL sites. We evaluate the forecast skill of the raw NCEP, downscaled NCEP, and NDFD forecasts for this time period to determine their performance in mountainous terrain.