A Precipitation Climatology from the 3-km High-Resolution Rapid Refresh

The High-Resolution Rapid Refresh (HRRR) model is now being run operationally at the National Centers for Environmental Prediction (NCEP) in Silver Springs, Maryland. A more advanced version of the model is run hourly in real time at the Global System Division (GSD) of the Earth System Research Laboratory (ESRL) in Boulder, Colorado. Since 2010, the HRRR has been running on a continental United States (CONUS) domain, providing forecasts out to 15 hours. In this paper, we present some mean quantitative precipitation forecast (QPF) results from the last three years of HRRR forecasts.

In the first part of the presentation, we present a comparison between HRRR 6-h QPFs and Stage IV quantitative precipitation estimations (QPEs), over the years of 2013 and 2014. The HRRR does well at capturing large-scale precipitation gradients, as well as local maxima and minima associated with local orography. However, the total amounts in the HRRR are substantially too high. We compare the frequency of exceedance of certain precipitation thresholds between the Stage IV QPEs and the HRRR 6-h QPFs, which reveals that the HRRR overforecasts most precipitation thresholds.

In the second part of the presentation, we present a similar comparison between HRRR 1-h QPFs and the MRMS 1-h QPEs. The MRMS QPE is less subjective and less dependent on the specific procedures of the River Forecast Centers (RFCs) in the western CONUS; we use it to examine whether the HRRR is in fact performing better in the western CONUS than is suggested by the Stage IV QPEs.