CW3E Event Summary: 14-18 September 2020

September 22, 2020

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Landfalling AR and Cutoff Low bring much-needed rainfall and improved air quality to the Pacific Northwest

  • A landfalling AR and cutoff low produced light-to-moderate precipitation (0.50–2 inches) over portions of western Washington and Oregon
  • Weak-to-moderate AR conditions persisted for more than 48 consecutive hours along the Oregon coast [AR3 based on the Ralph et al. (2019) AR Scale]
  • Precipitation and changes in wind direction and humidity significantly improved the air quality and alleviated the wildfire threat in western Washington and Oregon

Click images to see loops of GFS IVT/IWV analyses

Valid 0000 UTC 14 September – 0000 UTC 21 September 2020





Summary provided by C. Castellano, C. Hecht, J. Kalansky, N. Oakley, and F. M. Ralph; 22 September 2020