NOAA’s Weather Forecasting System Just Got a Major Update

The new version of the Global Forecast System could give Americans in the path of a hurricane an additional 36 hours to prepare compared to the old model

Satellite image of North America
A satellite image of North America taken on August 25, 2020. Smoke from wildfires can be seen rising from California and Hurricane Laura can be seen heading toward Louisiana and eastern Texas as the remnants of Marco swirl over the Southeast. NOAA

At the National Oceanic and Atmospheric Administration, predicting the weather one to two weeks out is job number one. And these days, the lion’s share of the data undergirding those predictions comes from a computer model called the Global Forecast System (GFS). As climate change drives shifting global weather patterns and continues to hurl a stream of severe hurricanes, wildfires, rainstorms and heat waves, the model has to keep up.

With those challenges in mind, last week NOAA announced a major update to GFS that will help it adapt to a world now in the grips of climate change, reports Rebecca Hersher for NPR.

NOAA says the new update will improve forecasts for hurricanes and extreme weather events, ocean waves, and weather systems looming high in Earth’s atmosphere, reports Matthew Cappucci for the Washington Post.

The new model, version 16.0, outperformed the old GFS in tests, per NPR. Improvements are pretty significant for this upgrade," Vijay Tallapragada, the head of the Modeling and Data Assimilation Branch for NOAA's Environmental Modeling Center, tells NPR.

In particular, the new model is better at forecasting hurricanes. "We found about a ten to 15 percent improvement in tropical cyclone track and intensity in the Atlantic Basin," Tallapragada tells NPR. That equates to roughly 36 hours of additional warning time for areas predicted to be in a storm’s path as it makes landfall.

This improved accuracy comes from tweaks to some of the physics equations the model uses to generate predictions and increases in the number and resolution of the initial observations factored into its forecasts, explains Michigan Live meteorologist Mark Torregrossa.

Director of the University of North Carolina's Institute of Marine Science Rick Luettich, who helped develop a widely used coastal circulation and storm surge model, tells Stacia Strong of North Carolina broadcast station WITN that the new GFS update has more detail, higher resolution and more layers.

“That means they chopped the problem up into smaller pieces, so hopefully that will give us more accurate results,” Luettich tells WITN. “What I see as being the real advantage is that continued progress, continued improvement in these global models... is the ability to better understand when storms or tropical systems are likely to get initiated.”

One way in which the new GFS model’s resolution has improved is in the vertical dimension of Earth’s atmosphere, according to the Washington Post. The new system partitions the sky into 127 vertical slices, while the old model used just 64.

“When we announced our upgrade to the GFS in 2019, we described it as replacing the engine of a car,” Louis Uccellini, director of NOAA’s National Weather Service, said in a news conference last week quoted by the Post. “With today’s upgrade, we’re adding more horsepower and more upgrades to the entire car as we move forward.”