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WoFSCast: A machine learning model for predicting thunderstorms at watch-to-warning scales
  • Montgomery L Flora,
  • Corey Potvin
Montgomery L Flora
The University of Oklahoma

Corresponding Author:[email protected]

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Corey Potvin
NOAA National Severe Storms Laboratory
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Abstract

Developing AI models that match or exceed the forecast skill of numerical weather prediction (NWP) systems but run much more quickly is a burgeoning area of research. Most AI-NWP models, however, have been trained on global ERA5 data, which does not resolve storm-scale evolution. We have therefore adapted Google’s GraphCast framework for limited-area, storm-scale domains, then trained on archived forecasts from the Warn-on-Forecast System (WoFS), a convection-allowing ensemble with 5-min forecast output. We evaluate the WoFSCast predictions using object-based verification, grid-based verification, spatial storm structure assessments, and spectra analysis. The WoFSCast closely emulates the WoFS environment fields, matches 70–80% of WoFS storms out to 2-h forecast times, and suffers only modest blurring. When verified against observed storms, WoFSCast produces a similar CSI as WoFS but with a lower frequency bias due to fewer false-alarm storms. WoFSCast demonstrates that AI-NWP can be extended to rapidly evolving, small-scale, chaotic phenomena like thunderstorms.
07 Sep 2024Submitted to ESS Open Archive
07 Sep 2024Published in ESS Open Archive