CW3E AR Update: 18 October 2021 Outlook

October 18, 2021

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Active weather is forecast to continue, bringing multiple landfalling ARs to the U.S. West Coast

  • The first AR is forecast to make landfall over Northern California on Tuesday evening, bringing moderate to strong AR conditions to the region
  • The second AR is forecast to make landfall on Thursday and is forecast to be stronger and last longer than the first AR
  • Current forecasts suggest the active pattern to continue with a third AR potentially making landfall between 23 and 25 October, but forecast uncertainty is high due to the long lead times
  • The Weather Prediction Center is forecasting >10 inches of precipitation over the higher elevations of the Pacific Northwest and Northern California due to these successive and potentially strong storms
  • Click images to see loops of GFS IVT & IWV forecasts

    Valid 1200 UTC 18 October – 1200 UTC 28 October 2021










    Summary provided by C. Hecht, Shawn Roj, J. Kalansky, and F. M. Ralph; 18 October 2021

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