The long-awaited upgrade to the US weather forecast model is here

Enlarge / Forecast output from the new version of the model, which goes into service today. (credit: NOAA)

Weather forecasters need a ton of knowledge and a fair bit of experience with local weather patterns to do their job well. They also need a good forecast model. These computer models take in measurements from weather stations on the ground, satellites in orbit, and balloons in between and then simulate the physics of weather forward in time a few days.

For the first time in about 40 years, the guts of the US model got swapped out for something new today. The upgrade brings us a new “Finite-Volume Cubed-Sphere” (or FV3) dynamical core, which simulates the basic atmospheric physics at the heart of this endeavor, a change that has been in the works for a while.

The new core had its origins in simulating atmospheric chemistry but ended up being adapted into other models. A few years ago, it was selected to replace the old core in the US Global Forecast System model. And for more than a year now, the new version of the model has been running in parallel so its results could be compared to the operational model.