FOUS30 KWBC 050740
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
240 AM EST Wed Nov 5 2025

Day 1
Valid 12Z Wed Nov 05 2025 - 12Z Thu Nov 06 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHWESTERN CALIFORNIA AND FAR SOUTHWESTERN OREGON, AS WELL AS THE
OLYMPIC MOUNTAINS AND ADJACENT PORTIONS OF COASTAL NORTHWEST WASHINGTON...

A strong atmospheric river impacting the PacNW will begin to wane 
in intensity through morning, gradually ending any residual flood 
impacts across outlooked coastal portions of CA/OR/WA. Additionally,
the Marginal Risk was maintained for locations farther inland
(upslope portions of the northern Sierras) in association with the
arrival of the strongest IVT from the AR. Rates are still largely
expected to peak near 0.5"/hr, but may briefly approach as high as
1"/hr locally. Any flood impacts are anticipated to be relegated 
to more sensitive terrain (i.e. burn scars). Areal average totals 
are expected to range from 1-3" (with much of that occurring prior 
to 18z), but localized 3-5" amounts may occur (highest chances
being in the upslope areas of Sierras and the Olympics). 

Churchill


Day 2
Valid 12Z Thu Nov 06 2025 - 12Z Fri Nov 07 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHWESTERN CALIFORNIA AND FAR SOUTHWESTERN OREGON, AS WELL AS THE
OLYMPIC MOUNTAINS AND ADJACENT PORTIONS OF COASTAL NORTHWEST WASHINGTON...

While the bulk of the forecast rainfall on Day 1 comes early with 
a distinct lull in moderate to heavy precipitation across the PacNW
through much of Wednesday evening and night, precipitation looks 
to ramp up once again by midday Thursday (Day 2) as yet another 
atmospheric river makes landfall. While this AR increasingly looks
to be significantly weaker and disjointed, additional rainfall 
totals of up to 2-3" are still possible for portions of CA/OR/WA 
(though forecast amounts have decreased to areal averages of 1-2".
The Marginal Risk areas were maintained for now, focused on the
regions where 2-5" of rainfall may occur through the end of Day 1.
There may be reconsideration of one or both of the Marginal Risk 
areas for futures updates, given the trend lower in the forecast 
rainfall amounts (while already being a relatively borderline
outlook based largely on expected wet antecedent conditions).  

Churchill


Day 3
Valid 12Z Fri Nov 07 2025 - 12Z Sat Nov 08 2025

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

Churchill
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