CW3E AR Update: 9 February 2021 Outlook

February 9, 2021

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Unsettled Weather Pattern Forecast to Bring Rain/Snow to Western U.S.

• A series of low-pressure systems and associated atmospheric rivers (ARs) are forecast to develop over the North Pacific Ocean and move toward the U.S. West Coast during the next 7 days
• The first two systems are forecast to bring brief periods of weak AR conditions to coastal areas, as well as light-to-moderate precipitation amounts
• The last system may bring a stronger, longer-duration AR event to Northern California and Oregon, but forecast uncertainty is still high at this time
• At least 1–3 inches of precipitation are forecast in the Pacific Coast Ranges, Sierra Nevada, Cascades, and higher terrain in north-central Utah, western Wyoming, and western Colorado during the next 7 days
• More than 4 inches of total precipitation and significant snowfall accumulations are possible in some locations

Click images to see loops of GFS IVT & IWV forecasts Valid 1200 UTC 9 February – 1200 UTC 17 February 2021

Summary provided by C. Castellano, C. Hecht, B. Kawzenuk, J. Kalansky, and F. M. Ralph; 9 February 2021

*Outlook products are considered experimental