National Weather Service United States Department of Commerce

Cold Front Moving Through the Northeast U.S. Monday; Atmospheric River to Impact the Pacific Northwest Midweek

A cold front will cross the Great Lakes and Northeast U.S. through Monday with gusty winds and areas of rain showers. A strong atmospheric river is expected to move into the Pacific Northwest by midweek bringing a threat for moderate to heavy rainfall, gusty winds, and mountain snows for parts of Washington, Oregon, northern California, and the Sierra Nevada. Read More >

12-hour helicity forecast

 

Figure 12: ETA 12 Hour Forecast of Surface to 3 kilometer Helicity
and Boundary Layer Wind valid 1200 UTC May 12, 1997.

 

18-hour helicity forecast

 

Figure 13: ETA 18 Hour Forecast of Surface to 3 kilometer Helicity
and Boundary Layer Wind valid 1800 UTC May 12, 1997.