NOAA Upgrades Global Weather Model Following 2020 HPC Additions

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The U.S. National Oceanic and and Atmospheric Administration (NOAA) said today it is upgrading its Global Forecast System (GFS) weather model to improve hurricane genesis forecasting, modeling for snowfall location, heavy rainfall forecasts and overall model performance.

In February 2020, NOAA announced it will triple if its weather and climate supercomputing capacity with the addition of two HPE-Cray supercomputers, an operational primary and backup, to be stood up in Manassas, VA, and Phoenix. The HPC systems — each with a 12 petaflop capacity — will be ready to implement model upgrades by early 2022 after a period of code migration and testing, NOAA said. The supercomputers will replace the existing Cray and Dell systems, “Luna” and “Mars,” in Reston, VA, and “Surge” and “Venus” in Orlando.

“Coupled with NOAA’s research and development supercomputers in West Virginia, Tennessee, Mississippi, and Colorado, which have a combined capacity of 16 petaflops, the supercomputing capacity supporting NOAA’s new operational prediction and research will be 40 petaflops,” NOAA said at the time of last year’s announcement.

Regarding today’s news, NOAA said that for the first time, the GFS will be coupled with a global wave model called WaveWatchIII that will extend current wave forecasts from 10 days out to 16 days and improve the prediction of ocean waves forced by the atmosphere. Coupling the GFS and wave models will streamline the National Centers for Environmental Prediction (NCEP) production suite by consolidating atmospheric and wave forecast data and distributing them together. The GFS resolution will increase by doubling the number of vertical levels, from 64 to 127. Improvements to atmospheric physics will enhance snow and precipitation forecasting capabilities in this latest upgrade as well.

“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 Louis W. Uccellini, Ph.D., director, NOAA’s National Weather Service. “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.”

In addition to GFS upgrades, NOAA is concurrently modernizing the Global Data Assimilation System (GDAS). This effort will allow the model to ingest more data from geostationary and polar-orbiting satellites, as well as flight-level wind, temperature and moisture observations from aircraft.

“These upgrades are part of the Next Generation Global Prediction System within the Unified Forecast System (UFS) framework, which is an ongoing effort to leverage the expertise of the broader weather community and expedite the research to operations pathway,” said Vijay Tallapragda, Ph.D., Chief of the Modeling and Data Assimilation Branch at NOAA’s Environmental Modeling Center (EMC). “By coupling the WaveWatchIII and GFS models, we will extend current wave forecasts and integrate wave forecasting into the global model to streamline model products.”

EMC conducted retrospective and real-time testing, covering part of the 2018 hurricane season and the entire period from May 10, 2019 to the present, for a comprehensive evaluation of the model upgrades. This latest version of the model, called GFSv16, showed improved forecast skills in many areas, including hurricane genesis lead times, snowfall forecasting, and the prediction of extreme rainfall events.

Today’s announcement marks the first major upgrade to the Finite-Volume Cubed-Sphere (FV3) dynamical core-based GFS, which replaced the spectral dynamical core-based GFS in June 2019. The GFS with the FV3 dynamical core brings together the superior physics of the global atmosphere with day-to-day reliability and speed of operational numerical weather prediction.