FOUS30 KWBC 120052 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 752 PM EST Thu Dec 11 2025 Day 1 Valid 01Z Fri Dec 12 2025 - 12Z Fri Dec 12 2025 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF WESTERN WASHINGTON AS WELL AS FOR NORTHERN IDAHO INTO FAR WESTERN MONTANA... ...Western Washington... GOES West water vapor imagery showed ridging off of the West Coast continuing to amplify downstream of an upper level trough/closed low near 160 W. The result has been a reduction in precipitable water values and low level winds along the coast of the Pacific Northwest. IVT values at 00Z ranged from about 250 kg/m/s across western Washington to ~450 kg/m/s across eastern Washington, and these values are forecast to continue lowering through 12Z Friday. Recent hourly rainfall over the upslope regions of western Washington was generally below 0.10 inches, but isolated pockets of greater than 0.10 inches in an hour remained across portions of the southern Cascades. As a warm front located along and west of the Washington coastline lifts north tonight, the ongoing moisture axis will also lift north with further weakening of IVT values, keeping rainfall light but steady into the Coastal Ranges and Cascades. Peak additional rainfall totals up to 1 inch (perhaps isolated spots near 1.5 inches) are expected through 12Z. While the expected overnight rainfall shouldn't amount to a significant contribution to additional flooding, a Marginal Risk was maintained given ongoing major flooding across the region and continued potential for landslides/debris flows within the higher terrain. Precautions and avoidance of flooded areas should be taken. ...Northern Idaho and Far Western Montana... Light to occasionally moderate rainfall is expected to continue across the northern Rockies of Idaho and Montana overnight. Westerly flow between 40-50 kt at 700 mb will help contribute to IVT values initially between 300-450 kg/m/s from eastern Washington downstream across the Rockies, but weakening to near 300 kg/m/s through 12Z. Rainfall intensities should remain light for the most part but pockets of moderate rainfall should be expected overnight and additional peak rainfall totals of 1 to 1.5 inches are expected through 12Z Friday. The Marginal Risk was maintained due to ongoing flooding throughout the region and the potential for additional impacts, although contributions to ongoing flooding concerns from tonight's rainfall should be minimal. Otto Day 2 Valid 12Z Fri Dec 12 2025 - 12Z Sat Dec 13 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 3 Valid 12Z Sat Dec 13 2025 - 12Z Sun Dec 14 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt