Forecasters said a final round of rain, snow and high winds were targeting the Pacific Northwest and Northern California regions on Friday.

The first storm was forecast to linger into the weekend and produce an additional 6-12 inches of rainfall, the weather service said. An atmospheric river prompted a high-risk warning for excessive rainfall along the Northern California coast.

A bomb cyclone occurs when a storm's pressure drops quickly, which intensifies the storm and ramps up wind gusts. Atmospheric rivers are a "long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics," according to the National Oceanic and Atmospheric Administration.