The High-Resolution Rapid Refresh (HRRR): Updates to Next Generation Convective-Scale Forecast Guidance With Operational Implementation in 2014

The 13-km Rapid Refresh (RAP) and 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) are hourly updating weather forecast models that use a specially configured version of the Advanced Research WRF (ARW) model and assimilate many novel and most conventional observation types on an hourly basis using Gridpoint Statistical Interpolation (GSI). Included in this assimilation is a procedure for initializing ongoing precipitation systems from observed radar reflectivity data, a cloud analysis to initialize stable layer clouds from METAR and satellite observations, and special techniques to enhance retention of surface observation information.

The HRRR is run hourly out to fifteen forecast hours over a domain covering the entire conterminous United States using initial and boundary conditions from the hourly-cycled RAP and is available in real-time to operational forecasters in both the private and public sectors. The HRRR is currently (August 2013) scheduled for operational implementation at NCEP in 2014.

The HRRR provides unique convective-scale forecast guidance with high spatial and temporal resolution leveraging both hourly updates and a sub-hourly output interval. In this presentation we will provide an overview of 2013 model and data assimilation updates to the HRRR forecast system, including the path towards operational implementation at the National Centers for Environmental Prediction (NCEP). We will provide examples of current HRRR forecast products including time-lagged ensemble probability forecasts to provide a measure of forecast likelihood. We will also highlight other HRRR applications and users including the aviation, severe weather and renewable energy communities (both public and private) with use by the National Weather Service (NWS) including the Storm Prediction Center (SPC), and collaborative projects such as the Federal Aviation Administration-sponsored CoSPA and the Wind Forecast Improvement Project (WFIP). We will also describe infrastructure associated with maintaining a reliable, but non-operational, real-time system with redundancy across two independent high-performance computer systems.