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

[Eugene]

Source: Ars Technica

IN YOUR NECK OF THE WOODS —

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

It’s been almost 40 years since the model got a new core.

SCOTT K. JOHNSON - 6/12/2019, 3:00 PM

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.

That evaluation also included retroactive forecasts (that is, forecast simulations with the same inputs that were available on each day in the past) of the past three years, with an additional focus on case studies of major hurricanes and common storm types.

The results have been a little mixed. The new core improves computational efficiency and allows some processes to be simulated at a higher resolution—unequivocal improvements. It also simulates the physics of water vapor more realistically. In a press conference today, NOAA scientists cited a number of areas where forecast improvements have been seen. Forecast tracks of hurricanes and the mid-latitude storms that frequently sweep across the US have both improved, they said, along with forecasts of hurricane strength. Forecast precipitation amounts were also cited as a key area of progress.

-snip-

Read more: https://arstechnica.com/science/2019/06/us-weather-forecasts-get-a-software-update/


Forecast output from the new version of the model, which goes into service today.

[klook]

1. Congratulations to NOAA

- despite all the Republican efforts to privatize this work, they persist in doing their jobs.

[shanny]

2. I was hoping to hear we adopted the European

system/model. It seems to be superior in the few cases I have seen them compared.