SAN FRANCISCO (KRON) — A second bomb cyclone is forming over the Pacific Ocean on Thursday that will re-launch a strong atmospheric river into the San Francisco Bay Area on Friday, forecasters said.

“A secondary surface cyclone is forecast to develop off the Northern California coast (Thursday). The GEFS model is forecasting AR 3-4 conditions from the Bay Area to Southern Oregon through Friday,” wrote meteorologists with the Center for Western Weather and Water Extremes.

KRON4 Meteorologist John Shrable explained, “Heaviest of rainfall moves north for much of the Bay Area today offering a comparatively calm day to yesterday. Tomorrow the atmospheric river (will) shift back southward, and with that, will bring the heaviest of rain directly to the core of the Bay Area.”

(Graphic courtesy UWCIMSS)

On Friday morning, “a deluge, super heavy rain” will pour on Marin and Sonoma counties, Shrable said. The storm will continue moving south over San Francisco, the East Bay, and the South Bay on Friday afternoon.

Between 3-7 inches of rain is forecast to drench the North Bay between Thursday-Friday, according to the National Weather Service Bay Area. Up to 3 inches of rain is forecast for the rest of the Bay Area and Central Coast.

The cold front will bring widespread impacts, including potential flooding, the NWS said.

On Wednesday, Santa Rosa recorded its second-wettest day in more than 100 years, the NWS reported. Seven inches of rain fell on Santa Rosa within 24 hours.

Santa Rosa police officer Ken Ferrigno carries a young girl through a flooded parking lot outside of Sutter Health on November 21, 2024, in Santa Rosa. (Photo by Justin Sullivan/Getty Images)

The NWS wrote, “The North Bay received a tremendous amount of rain (Wednesday), even surpassing our high expectations. We aren’t expecting quite as much rain (Thursday), but it will still be substantial with an additional 1-3 inches in the valleys and more in the mountains. As such, flooding impacts will continue. Winds will remain strong through the day, leading to more tree damage.”

A car sits submerged in floodwater on November 21, 2024, in Windsor, California. (Photo by Justin Sullivan/Getty Images)

A Wind Advisory will remain in effect from 10 p.m. Thursday through 10 p.m. Friday along the entire Bay Area coastline and at high elevations. Wind gusts will reach 50 mph in some areas, NWS said.

The system is considered a bomb cyclone, which happens when a cyclone intensifies rapidly.