CW3E AR Update: 12 November 2020 Outlook

November 12, 2020

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Active weather pattern expected to bring heavy rainfall and snowfall to portions of the Western U.S.

  • A series of storms and landfalling ARs are forecast to bring significant precipitation to portions of Northern California and the Pacific Northwest over the next 7 days
  • AR 4/AR 5 conditions (based on the Ralph et al. 2019 AR Scale) are possible over coastal Oregon and Washington in association with the second landfalling AR
  • The highest 7-day precipitation amounts (5–10 inches) are forecast over the Pacific Coast Ranges and Cascade Mountains
  • More than 2 feet of snow is possible in the higher elevations of the Washington Cascades during the next 48 hours

Click images to see loops of GFS IVT & IWV forecasts

Valid 0000 UTC 12 November – 1200 UTC 19 November 2020









Summary provided by C. Castellano, C. Hecht, B. Kawzenuk, and F. M. Ralph; 12 November 2020

*Outlook products are considered experimental