CW3E AR Update: 10 November 2020 Outlook

November 10, 2020

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An active pattern is forecast to bring multiple landfalling atmospheric rivers to the Pacific Northwest and Northern California

  • The first AR is forecast to make landfall on 13 November, though there is currently large ensemble uncertainty in onset and overall duration of AR conditions
  • The second AR is forecast to make landfall over the Pacific Northwest on 15 November but is also associated with large ensemble and model-to-model uncertainty
  • The GEFS control member is currently suggesting that first AR could bring AR 2 conditions to Northern CA and Southern OR while the second AR could bring AR 4 conditions to Southern OR
  • The NOAA Weather Prediction Center is currently forecasting >10 inches of precipitation over the high elevations of the Coastal, Olympic, and Cascade Mountain Ranges during the next 7 days.

Click images to see loops of GFS IVT & IWV forecasts

Valid 0600 UTC 10 November – 0600 UTC 20 November 2020









Summary provided by C. Hecht, B. Kawzenuk, C. Castellano, J. Kalansky, and F. M. Ralph; 10 November 2020

*Outlook products are considered experimental