High-Resolution Rapid Refresh

High-Resolution Rapid Refresh
Name	High-Resolution Rapid Refresh
Abbreviation	HRRR
Type	Numerical weather prediction
Developer	NOAA / ESRL / GSL
Released	30 September 2014
Website	https://rapidrefresh.noaa.gov/hrrr/

High-Resolution Rapid Refresh. The High-Resolution Rapid Refresh is a real-time, convection-allowing weather forecast model operated by the National Oceanic and Atmospheric Administration. It provides highly detailed, frequently updated forecasts for the contiguous United States, focusing on critical short-term phenomena like thunderstorms, tropical cyclones, wildfire behavior, and aviation hazards. The model's rapid update cycle and fine spatial resolution make it a cornerstone tool for operational meteorologists at institutions like the National Weather Service and the Storm Prediction Center.

Overview

The primary function of this system is to generate frequent, high-fidelity forecasts to support severe weather warning operations. It assimilates a vast array of observational data, including from the Next Generation Weather Radar network, the Geostationary Operational Environmental Satellite system, and surface Automated Surface Observing System stations. This continuous data ingestion allows the model to quickly adjust to evolving atmospheric conditions, providing superior short-range guidance compared to models with longer update cycles. Its outputs are critical for forecasting events like tornado outbreaks, flash flooding, and winter storm impacts.

Development and Implementation

Development originated within the Earth System Research Laboratory, now the Global Systems Laboratory, building upon earlier systems like the Rapid Refresh model. A key milestone was its initial operational implementation on the Weather and Climate Operational Supercomputing System in September 2014. The project has involved extensive collaboration with the National Centers for Environmental Prediction and the National Weather Service. Subsequent major upgrades have expanded its domain and improved its physics packages, with development support also coming from the University of Oklahoma and the National Center for Atmospheric Research.

Technical Specifications

The operational version runs on a 3-km horizontal grid covering the contiguous United States and portions of surrounding oceans. It produces forecasts out to 48 hours, with a new cycle initiated every hour. The model uses the advanced Advanced Research WRF core for its dynamic framework. It incorporates sophisticated schemes for representing cloud microphysics, planetary boundary layer processes, and land-surface interactions. The system's data assimilation component, a hybrid ensemble Kalman filter, integrates radar reflectivity and radial velocity data directly, which is crucial for initiating realistic convection.

Operational Use and Applications

Forecasters at local National Weather Service offices rely heavily on its guidance for issuing timely severe thunderstorm and tornado warnings. The Storm Prediction Center utilizes its output for Convective outlook products and mesoscale discussions. Specialized applications include the HRRR-Smoke version, which models smoke dispersion from wildfires for agencies like the United States Forest Service. The Federal Aviation Administration uses its forecasts for anticipating aviation hazards such as turbulence, icing, and convective weather impacts on air traffic control.

Model Performance and Validation

Continuous evaluation is conducted by the Global Systems Laboratory and the National Weather Service's Meteorological Development Laboratory. Performance is benchmarked against other models like the North American Mesoscale Model and the High-Resolution Ensemble Forecast system. Validation metrics often focus on the accuracy of quantitative precipitation forecasts, the timing and location of convective initiation, and the depiction of boundary layer evolution. Independent studies by entities like the University of Utah and the National Severe Storms Laboratory have consistently demonstrated its skill in forecasting mesoscale convective systems and other high-impact weather.

Future Developments

Ongoing research aims to increase the forecast horizon and further enhance data assimilation techniques, including better use of observations from the Joint Polar Satellite System. Efforts are underway to couple the atmospheric model with more sophisticated hydrology and wave model components. A major focus is the development of a sub-kilometer, large-eddy simulating version known as the Rapid Refresh Forecast System, which promises even finer detail. These advancements are supported by continued upgrades to the computational infrastructure provided by the Weather and Climate Operational Supercomputing System.

Category:Numerical climate and weather models Category:National Oceanic and Atmospheric Administration Category:Weather forecasting