NOAA's New Rapid Refresh Forecast System Goes Live, Extending Forecast Lead Time to 84 Hours
The National Oceanic and Atmospheric Administration (NOAA) announced that its next-generation Rapid Refresh Forecast System (RRFS) entered operational service with the National Weather Service on November 3, 2026. It is the biggest upgrade to U.S. regional weather modeling in years: the system updates every hour, covers all of North America, and extends forecast lead time by 36 hours over the previous workhorse model.
RRFS combines the biggest strengths of NOAA's existing regional models: the hourly updates and 3-kilometer grid detail of the High Resolution Rapid Refresh Model (HRRR), which issues forecasts for each 3-kilometer square of land surface, and the continental-scale domain of the North American Mesoscale model (NAM). Combined, the new system extends forecast lead time for the contiguous United States to 84 hours, compared with the HRRR's 48 hours.
RRFS covers North America including Alaska, Hawaii and Puerto Rico, along with Canada, Mexico, Central America and the Caribbean, with enough detail to predict high-impact, small-scale events such as thunderstorms, tornadoes and flash floods, and it provides seamless forecasts for coastal and offshore areas that previously required forecasters to switch between models. Its companion ensemble system, REFS, runs multiple simulations on the same 3-kilometer grid and can calculate the probability of local events such as severe hail or a flash flood, information NOAA called extremely valuable for emergency managers, first responders and broadcasters.
RRFS also brings fire and smoke forecasting into operations for the first time. It includes an on-demand mode with an even finer 1.5-kilometer grid for fire weather, complex winter weather over travel corridors and severe thunderstorms. Its RRFS-SD component is NOAA's first high-resolution smoke and dust model to transition to National Weather Service operations, predicting where aerosol particles from fires and dust storms will travel across North America over the next 18 to 84 hours, including high-altitude smoke that affects aviation and ground-level particulates that affect health and visibility. It also carries NOAA's first Hourly Wildfire Potential forecast, which evaluates the risk of rapid, intense wildfire spread.
"The transition of RRFS from research to operations represents a major step towards modernizing NOAA's weather forecast modeling suite," said NOAA Administrator Neil Jacobs. "RRFS extends the reach of some of our best capabilities and delivers more accurate, earlier forecasts to support Americans' safety and security." Ken Graham, director of the National Weather Service, said: "RRFS is the biggest improvement to our regional weather models in years. The higher precision provided by this model helps our forecasters issue better forecasts, warnings, and decision support for local emergency managers."
As RRFS goes operational, NOAA will discontinue five outdated regional modeling systems, including the North American Mesoscale (NAM), the Short Range Ensemble Forecast and the High Resolution Ensemble Forecast, unifying its operational modeling suite. RRFS was developed by NOAA's Global Systems Laboratory and the National Weather Service's modeling offices together with academic institutions, other federal agencies and international partners. Steve Thur, NOAA's assistant administrator for research, said RRFS is a great example of how research supports one of NOAA's most critical missions, and that the public will be better informed because of NOAA research.
Source: National Oceanic and Atmospheric Administration
Published by GSM · USA (original Chinese edition)
Photo: 图：美国国家海洋和大气管理局局长 Neil Jacobs 官方肖像，国家海洋和大气管理局发布。 / Photo: Official portrait of NOAA Administrator Neil Jacobs, released by the National Oceanic and Atmospheric Administration.
