NOAA launches updated American Weather Model

The American Model that meteorologists at WRAL analyze and show on TV underwent this upgrade on Wednesday afternoon. When you see the American Model on WRAL it is now the upgraded GFS-FV3. Before becoming operational, the GFS-FV3 underwent testing from scientists across the county. This data was available for real time testing and evaluations over the past year, including during the 2018 Atlantic hurricane season. NOAA states in their press release that “The scientific and performance evaluation shows that the upgraded FV3-based GFS provides results equal to or better than the current global model in many measures.”

A report released by the NOAA Environmental Modeling Center in early April lists some of the improvements scientists found comparing the GFS and GFS-FV3 over the past year. A key improvement found was that tropical cyclone tracks improved up to day 5 (especially in the Pacific) as well as improved intensity forecasts. A statistical evaluation also shows significant improvements over the previous GFS regarding 5-day upper air forecasts and improved midlatitude cyclone forecasts. One of the concerns raised by forecasters during testing included that its winter storm forecasts were too cold and predicted too much snow. The report released by EMC in early April showed that this issue has been partially fixed but there is still room for improvement. Another concern with tropical cyclones was that the GFS-FV3 forecast speed tended to run slow.

The advancements in the new model include both hardware updates and new code. The new dynamical core was made possible through massive computing upgrades. NOAA increased performance on their supercomputers by nearly 50% and increased storage by nearly 60%. This was an important factor that allowed them to test both the “new” and the “old” GFS side-by-side over the past year. In addition, the model physics have been updated with the newest research findings. The GFS FV3 also includes updated data assimilation properties which allows new and updated data to be integrated into the GFS code in real time. This is a key property so the model can initialize more accurately - In order to produce an accurate forecast for the future you need an accurate input of what’s happening right now.

Overall, there is still work to be done to improve the GFS-FV3 but the overview statistical improvement scores are impressive. The European Weather Model (ECMWF) also underwent substantial upgrades this week.