CW3E Event Summary: 16-19 September 2021

September 21, 2021

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Atmospheric River Brings Much Needed Precipitation to the Pacific Northwest

• A strong atmospheric river (AR) made landfall over Washington and Oregon during 17th of September
• Portions of coastal Washington and Oregon experienced AR 3/AR 4 conditions (based on the Ralph et al. 2019 AR Scale)
• More than 5 inches of precipitation fell in parts of the Olympic Peninsula and North Cascades
• This precipitation fell while numerous large wildfires were burning across the Pacific Northwest and Northern California
• While this recent rain didn’t end all current fire activity and the fire season it brought much need moisture to the fuels across the region

Click images to see loops of GFS IVT & IWV forecasts Valid 0000 UTC 14 September – 1800 UTC 22 September 2021

Summary provided by C. Hecht, C. Castellano, J. Kalansky, and F. M. Ralph; 21 September 2021

*Outlook products are considered experimental