Atmospheric River Forecast

From the Center for Western Weather and Water Extremes.

“CW3E AR Update: 14 September 2020 Outlook

“September 14, 2020

“Click here for a pdf of this information.

“Update on the Atmospheric River forecast to make landfall over the Pacific Northwest

  • An AR that is forecast to make landfall early this week could bring much needed precipitation to parts of Washington, Oregon, and potentially Northern California.
  • As time has progressed closer to verification, ensemble agreement associated with AR landfall timing and initial IVT magnitude has increased.
  • The parent low pressure system is forecast to cut off from the upper-level flow and become quasi-stationary off the PNW coast.
  • Forecast duration of the event is currently exhibiting larger uncertainties as the cut-off low remains off the coast and moves higher IVT magnitudes onshore.
  • Forecast precipitation accumulations from the Weather Prediction Center have primarily decreased since our last outlook, though the ECMWF has trended towards a larger event (max. precip. accumulations of 1.5–2.4 in. over Coastal OR and WA).
  • Forecasts continue to suggest that a majority of CA will remain dry with lighter precipitation rates over far Northern CA.”

Retrieved September 15, 2020 from

Be well everyone!

About David H Lukenbill

I am a native of Sacramento, as are my wife and daughter. I am a consultant to nonprofit organizations, and have a Bachelor of Science degree in Organizational Behavior and a Master of Public Administration degree, both from the University of San Francisco. We live along the American River with two cats and all the wild critters we can feed. I am the founding president of the American River Parkway Preservation Society and currently serve as the CFO and Senior Policy Director. I also volunteer as the President of The Lampstand Foundation, a nonprofit organization I founded in 2003.
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