Overview

• National Weather Service forecasts that rain will begin Thursday night and peak Friday into Saturday across western Washington and Oregon, with at least a quarter-inch guaranteed statewide and an 80–95% chance Portland will see 0.5 inches
• Weather models indicate precipitable-water values near record levels and predict 2 to 6 inches of rain in mountain areas by Saturday afternoon
• NWS offices have warned of gusty south winds and urged residents to prepare for rapid runoff and localized flooding
• A Gulf of California moisture surge and mesoscale convective vortex will revive the North American Monsoon this weekend, bringing thunderstorms and measurable rain to Phoenix and parts of Arizona, New Mexico, Utah and Colorado
• Meteorologists say the heavy early-season rains will help ease drought and firefighting efforts even as they heighten flash-flood danger on dry soils and steep terrain