FOUS30 KWBC 200718
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
318 AM EDT Fri Mar 20 2026

Day 1
Valid 12Z Fri Mar 20 2026 - 12Z Sat Mar 21 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
WESTERN WASHINGTON STATE...

At the beginning of the forecast period, a stubborn atmospheric 
river is forecast to weaken as a surface low and attendant cold 
front progress eastward into the Pacific Northwest. Even so, 
moderate IVT values on the order of 500-700 kg/m * s directed into 
the WA coastline from 12-18Z should maintain the threat of locally 
heavy rainfall ahead of the front. While hourly rainfall rates will
likely remain below 0.5 inches per hour, isolated instances of 
excessive rainfall remain possible in upslope regions of the 
Olympics and Cascades owing to antecedent rainfall over the last few days.

Asherman


Day 2
Valid 12Z Sat Mar 21 2026 - 12Z Sun Mar 22 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Asherman


Day 3
Valid 12Z Sun Mar 22 2026 - 12Z Mon Mar 23 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Asherman
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