NOAA marked an important milestone in numerical weather modeling this week with the implementation of a next-generation rapid-update forecast system by the National Weather Service.

The new Rapid Refresh Forecast System (RRFS) delivers the most detailed, hourly-updating, short-term forecasts for North America with longer forecast lead times than ever before. RRFS replaces a patchwork of aging regional forecast systems, ultimately improving storm-scale forecasts of severe weather, aviation hazards, air quality, and winds.

"RRFS is the biggest improvement to our regional weather models in years," said Ken Graham, director of NOAA’s National Weather Service. "The higher precision provided by this model helps our forecasters issue better forecasts, warnings, and decision support for local emergency managers and meet our core mission to save lives and protect property."

CIRES scientists in NOAA’s Global Systems Laboratory have played critical roles across the full spectrum of RRFS development. They’ve helped improve the physics that drive the model, make better use of atmospheric observations, advance the way RRFS incorporates smoke and dust into its forecasts, optimize the end-to-end workflow, and verify and validate the model’s output.

"It is exciting to see RRFS become operational. This is a tremendous achievement for the entire weather modeling community," said Guoqing Ge, a CIRES research scientist who helped develop RRFS. "I am proud of the breadth and depth of contributions made by CIRES scientists throughout this process, as part of a great collaborative effort across NOAA and its partners."

The RRFS combines the capabilities of two existing NOAA weather models to provide more accurate short-term forecasts over all of North America. The RRFS also extends forecast lead time for the contiguous United States to seven days, compared to the four days of NOAA’s existing weather models. RRFS provides enough forecast detail to predict high-impact, small-scale events such as thunderstorms, tornadoes, and flash floods. RRFS also features seamless predictions for coastal and offshore areas that previously required forecasters to switch between different weather models.

RRFS can also forecast smaller-scale phenomena like fire weather conditions, complex winter weather over travel corridors, and severe thunderstorms. Meteorologists can use this mode to focus on areas where high-impact weather is imminent or actively developing.

Scientists with NOAA’s Global System Laboratory (GSL) also developed RRFS-SD (Smoke and Dust), NOAA’s first high-resolution smoke and dust model, that can predict when and where aerosol particles from fires and dust storms will travel across North America over the next 18 to 84 hours. RRFS-SD predicts both high-altitude smoke levels, which affect aviation and air temperatures, and ground-level particulates that most directly affect human health and surface visibility. This gives agencies data they need to issue air quality alerts. The RRFS-SD also includes NOAA’s first Hourly Wildfire Potential forecast that evaluates the risk of rapid, intense wildfire spread.

The RRFS and REFS emerged from a coordinated development effort between NOAA GSL, the NWS Office of Modeling and Development, and a network of partners that includes other NWS entities, academic institutions, other federal agencies, and international partners.

“RRFS is a great example of how research supports one of NOAA’s most critical missions,” said Steve Thur, Assistant Administrator for NOAA Research. “Our scientists worked closely with their colleagues at NWS to improve forecasts for all of North America. The public will be better informed because of NOAA research."