Evolution of the high resolution rapid refresh (HRRR) model and its role in convective weather guidance for air-traffic management

The High Resolution Rapid Refresh (HRRR) is a 3-km, convection resolving model, run hourly in real-time at the Global System Division (GSD) of the NOAA Earth System Research Laboratory (ESRL). The WRF-ARW-based HRRR is run out to fifteen hours over a domain covering the entire continental United States (CONUS), using initial and boundary conditions from an hourly-cycled 13-km mesoscale model, formerly the Rapid Update Cycle (RUC), and currently the Rapid Refresh (RR). The RR (and RUC) includes a diabatic digital filter-based radar reflectivity data assimilation procedure to improve specification of the divergent component of horizontal wind in areas of precipitation.

HRRR gridded output is used as input to an automated convective weather forecast product known as CoSPA. During the summer of 2011, an operational performance evaluation of CoSPA was conducted by the FAA to assess its impact on air traffic management decision-making.

During the past year additional resources have been implemented to further improve the HRRR convective forecast guidance. These additional resources include both an in-house multi-scale verification system and a parallel (shadow) HRRR model whereby impacts of model changes are assessed in both real-time and thru retrospective forecasts.

In this presentation, we will include an updated overview of the workflow comprising real-time HRRR model forecast production along with results from the in-house assessment of changes to the HRRR model including the adoption of the RR as a parent mesoscale model. Evaluation of model changes will include regional, diurnal (valid-time) and lead-time stratification of verification statistics to highlight improvements addressing known deficiencies in HRRR convective weather forecasts. Case studies highlighting comparisons of the parallel and real-time HRRR will also be shown.

This research is partially in response to requirements and funding by the Federal Aviation Administration (FAA). The view expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.