SAVANNAH, Ga. (WSAV) — Hurricane forecasting and accuracy have been greatly improved since 2016 when Hurricane Matthew hit. It’s thanks to an upgrade to one of the two main computer forecast models we use to make forecasts and forecast cones becoming more accurate.
Updating Forecast Models
The Global Forecasting System (GFS), also known as the American model, has been improved.
The American model was created and operated by the National Oceanic and Atmospheric Administration (NOAA) and the National Center for Environmental Prediction. It runs four times a day and gives predictions up to 16 days in the future. The computing power used to create these models can process 8 quadrillion calculations every second, so the computer that runs these calculations is in the top 30 fastest computers in the world.
With the upgrade to the GFS, for the first time, it will be coupled with a global wave model called WaveWatch III. This will improve the prediction of ocean waves forced by the atmosphere.
Also with this upgrade, the new GFS will ingest more data from geostationary and polar-orbiting satellites, as well as flight-level wind, temperature and moisture observations from aircraft.
This means we should see improvements in our hurricane forecasting, modeling for snowfall location, heavy rainfall forecasts and overall model reliability.
To prove how well the GFS is now performing, NOAA’s Environmental Modeling Center conducted retrospective and real-time testing. They looked back at part of the 2018 hurricane season and the entire period from May 10, 2019, to the present. The latest GFS model, which is called GFSv16, showed improved forecast skills in many areas.
The Cone of Uncertainty
For hurricane forecasting, with the upgrades to the computer models, National Hurricane Center forecast cones are now not as big — indicating a smaller margin of error for projected paths.
The table below compares the margin of error at each forecast cone point between the cone used in 2017 to the new one for 2021.
|2017 (Nautical Mile Error)||Hours||2021 (Nautical Mile Error)|
As forecast model improvements continue to happen, the National Hurricane Center forecast cones will continue to shrink in size as the margin for error continues to become less.