Washington & Oregon – After days of relentless rain, the atmospheric river that soaked the Pacific Northwest is finally winding down. The system, which dumped 5 to 10+ inches of rain across portions of western Washington and northwest Oregon, is weakening today as a mid- to upper-level ridge builds along the West Coast.
While the heaviest downpours have eased, the damage and danger persist. Rivers remain swollen, and major flooding continues in several basins. Landslides are still possible — especially in steep terrain and near recent burn scars — as saturated soils struggle to drain.
Residents are urged to stay alert for flood warnings and avoid driving through high water as runoff keeps local creeks and rivers above flood stage through Friday.
Meteorologists say this shift marks a turning point in the regional pattern. The amplifying ridge not only cuts off the Pacific moisture feed but also sets the stage for a major temperature drop inland. As the ridge strengthens, Arctic air will dislodge southward into the Northern Plains late Thursday, ushering in a sharp transition from Pacific storms to bitter winter cold across the central U.S.
In short — the Northwest dries out, but the nation’s midsection braces for the coldest air of December so far.
Expect calmer, cooler conditions across Seattle and Portland by the weekend, while Montana, the Dakotas, and Minnesota see a blast of Arctic air beginning tonight and spreading south through Friday.
