Weather Service Upgrades Models to Better Forecast Extreme Events

WASHINGTON – The National Weather Service has significantly upgraded its longstanding forecast model to better predict extreme weather events such as hurricanes, blizzards and downpours, as well as day-to-day weather across the U.S.

While it is easy to get bogged down in the jargon of the science behind the move, what the Weather Service has done is couple its standard weather model — the Global Forecast System — with an ocean wave model called WaveWatch II.

By combining data from the upper layers of the atmosphere with increased information about the status of ocean waves being pushed by winds, forecasts here in the U.S. will catch up to a popular European weather model that many experts have long considered superior.

Tests for the past two years show the upgrade, which kicked in Monday, forecast heavy rains and snowfall 15% better five days out and improved hurricane and tropical storm tracks by more than 10%, better pinpointing storm formation five to seven days in advance.

“This substantial upgrade to the GFS, along with ongoing upgrades to our supercomputing capacity, demonstrates our commitment to advancing weather forecasting to fulfill our mission of protecting life and property,” said National Weather Service Director Louis W. Uccellini, Ph.D., in a written statement. 

“Today’s upgrade also establishes a strong foundation for further planned enhancements that will allow for the assimilation of even more data into the model,” he said.

In addition to the weather modeling upgrade, NOAA is concurrently modernizing the Global Data Assimilation System. 

This effort will allow the weather model to utilize more data from geostationary and polar-orbiting satellites, as well as flight-level wind, temperature and moisture observations from aircraft.

Forecasters say this new model does not predict more rain and snow than actually arrives, which its predecessor had a tendency to do. 

The new model was significantly better at forecasting the massive Colorado snowstorm earlier this month, predicting the storm arrival time and snow amounts far more accurately than the older version, said Vijay Tallapragada, chief of modeling at the agency’s Environmental Modeling Center, during a briefing for reporters on Monday.

Internal studies also showed the new model was generally more accurate earlier on downpours in the Southeast in February 2020, Hurricane Dorian in 2019 and Hurricane Michael in 2018.

“This is for the general day-to-day forecasting and for the extreme events, and you’ve got to get both right,” Uccellini said.