A bomb cyclone is driving an atmospheric river to California

San Francisco Chronicle / 11-18-24

A rapidly intensifying low-pressure system over the Pacific Ocean is predicted to surpass the meteorological criteria for a “bomb cyclone” off the Washington coast Tuesday.

Unlike the bomb cyclone that made landfall over San Francisco in March 2023, this week’s storm will spin up hundreds of miles away from California. However, the storm will drive a major atmospheric river toward California beginning Tuesday evening.

SNIP

Between 10 and 20 inches of rain could fall in the mountains of Northern California in Mendocino, Humboldt, Del Norte and Shasta counties. Heavy rain is predicted to extend down to the North Bay, where 6 to 10 inches could fall in Santa Rosa through Saturday.

San Francisco and Oakland are on a razor’s edge. Only 2 to 3 inches of rain is currently predicted south of the Golden Gate, but a slight southerly shift of the atmospheric river could result in much more.

Link (paywall): https://www.sfchronicle.com/weather/article/bomb-cyclone-california-rain-snow-forecast-19925793.php

Rain is expected to start in Northern California on Wednesday morning, November 19.