Overview

• A Gulf of Alaska low will channel a moisture-rich atmospheric river into western Washington, northwest Oregon and coastal British Columbia from Friday night through Saturday.
• The National Weather Service forecasts 3–5 inches of rain in mountain areas and 0.5–1.5 inches in lowlands, with some B.C. coastal regions facing a month’s worth of rain in just two to three days.
• NWS hydrologic outlooks warn that hardened, drought-stricken soils will limit absorption and elevate the risk of heavy surface runoff and localized flooding.
• The Bay Area is expected to see little rainfall but gusty northwest winds of 25–35 mph and noticeably cooler weekend temperatures.
• A revived North American Monsoon will boost thunderstorm chances across Arizona, New Mexico, Utah and Colorado, with Phoenix poised for its first measurable rain in over six weeks.