CW3E AR Update: 12 February 2021 Outlook

February 12, 2021

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Multiple ARs forecast to impact the Western U.S. this weekend into early next week

  • A weak AR brought light-to-moderate precipitation to Northern and Central California yesterday
  • A second AR and associated surface cyclone will approach the U.S. West Coast today, bringing hazardous winter weather to lower elevations in western Washington and northwestern Oregon
  • A third and stronger AR is forecast to make landfall across California and Oregon on Sunday
  • The third AR is forecast to bring AR 2/AR 3 conditions to portions of coastal California and Oregon, but the heaviest precipitation is expected to remain far north of the AR 3 area in California due to the unfavorable orientation of the IVT vectors (parallel to the coast)
  • More than 5 inches of total precipitation are possible in portions of the Pacific Coast Ranges and Cascades during the next 5 days, with the highest amounts forecast in the Oregon Cascades

Click images to see loops of GFS IVT & IWV forecasts

Valid 0600 UTC 12 February – 0600 UTC 17 February 2021








Summary provided by C. Castellano, C. Hecht, J. Kalansky, N. Oakley, and F. M. Ralph; 12 February 2021

*Outlook products are considered experimental