Powerful Atmospheric River Storm Hits Northwest, Bringing Hurricane-Strength Winds and Heavy Rain

A fierce storm system, with the strength of a hurricane, is set to unleash damaging winds, massive ocean waves, and an atmospheric river over Northern California this week. The powerful weather event, which began Tuesday night, is expected to cause widespread rain, particularly in the Bay Area, and extend through the weekend.

The first major atmospheric river of the season is bringing significant rainfall to the region, with predictions that as much as 20% of the annual rainfall for Northern California could fall in just a few days. The heaviest downpours are expected in the North Bay, where up to a month’s worth of rain could accumulate. While much of the region will see rain on Wednesday, the storm is forecasted to continue through Friday, with Friday bringing the heaviest rainfall to areas south of San Francisco.

Forecasters have issued a rare “high risk” warning for excessive rainfall on Thursday, especially in northwest California, where up to 16 inches of rain could fall. This level of rainfall could lead to dangerous flooding, especially in areas vulnerable to flash floods. However, since it is still early in the wet season, the risk of large-scale flooding is somewhat mitigated by the dry conditions of the ground and the relatively low water levels in rivers.

The storm is connected to a “bomb cyclone” forming over the northeastern Pacific Ocean, which could bring one of the lowest barometric pressure readings ever recorded in the area. Bomb cyclones rapidly intensify, and the presence of the atmospheric river has provided extra fuel for this storm’s explosive development. While the worst of the storm will remain offshore, the Bay Area to Seattle can expect strong winds as the storm strengthens, with gusts potentially reaching 70 mph in parts of Northern California, Oregon, and Washington. In some areas, blizzard conditions are also possible, especially in higher elevations like the Cascades.

Meteorologists are closely monitoring the Pacific Ocean’s conditions, as they predict more atmospheric rivers could develop this winter. The winter outlook from NOAA indicates that while the Pacific Ocean is currently in a neutral phase, which can lead to unpredictable weather, a marginal La Niña pattern could develop. This would favor more frequent atmospheric rivers in the Pacific Northwest, potentially leading to a stormy season for the region.

As this powerful storm system makes its way across the West Coast, it serves as a reminder of the region’s vulnerability to extreme weather and the unpredictable nature of winter storms.