Subj : HVYRAIN: Excessive Rainfa To : All From : Mike Powell Date : Wed Nov 05 2025 10:01:38 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 $$ --- SBBSecho 3.28-Linux * Origin: ILink: CCO - capitolcityonline.net (454:3/105) .