CW3E AR Update: 13 September 2021 Outlook

September 13, 2021

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An increase in activity over the Eastern Pacific is forecast to bring multiple ARs to the Pacific Northwest

  • The first AR is forecast to be weak and brief, bringing as much as 1 inch of precipitation to far Northwestern Washington
  • The second AR is forecast to bring much stronger and a longer duration of AR conditions to the Pacific Northwest, though there is currently much higher ensemble spread in timing, magnitude, and overall duration of AR conditions
  • ~12 GEFS ensemble members are predicting the second AR to bring AR 4 or higher conditions to Coastal Oregon
  • The NWS Weather Prediction Center is currently forecasting as much as 7 inches of precipitation to fall across several high elevation locations in the Pacific Northwest during the next seven days
  • While early season ARs tend to produce less precipitation than their mid-winter counterparts, any precipitation that these two ARs produce will bring much needed relief to the numerous active wildfires and drought conditions in the Pacific Northwest
  • Click images to see loops of GFS IVT & IWV forecasts

    Valid 1200 UTC 13 September – 1200 UTC 23 September 2021








    Summary provided by C. Hecht, C. Castellano, J. Kalansky, and F. M. Ralph; 13 September 2021

    *Outlook products are considered experimental