CW3E AR Update: 7 December 2020 Outlook

December 7, 2020

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Multiple AR landfalls possible along the U.S. West Coast during the next 7 days

  • An AR over the Northeast Pacific Ocean will bring a period of AR conditions to southern British Columbia and Washington today and tomorrow
  • AR 2/AR 3 conditions (based on the Ralph et al. 2019 AR Scale) are forecast over coastal Washington in association with this landfalling AR
  • More than 2 inches of precipitation are possible across the Olympic Peninsula and North Cascades
  • A second AR may impact the U.S. West Coast this weekend, but forecast uncertainty is still very large

Click images to see loops of GFS IVT & IWV forecasts

Valid 1200 UTC 7 December – 1200 UTC 14 December 2020







Summary provided by C. Castellano, C. Hecht, J. Kalansky, B. Kawzenuk, and F. M. Ralph; 7 December 2020

*Outlook products are considered experimental