San Francisco

'Pretty Potent' Atmospheric River to Slam Bay Area With Heavy Rain, Strong Winds

'It could be a nasty system,' one meteorologist said. 'The Wednesday morning commute could be pretty brutal'

What to Know

  • Flash flood watch in effect between 10 p.m. Tuesday and 10 a.m. Thursday for much of the Bay Area
  • High wind warning in place between 10 p.m. Tuesday and 10 a.m. Thursday for spots along the coast and in the hills above 1,000 feet
  • Wind advisory in effect between 10 p.m. Tuesday and 10 a.m. Thursday for interior valleys across the Bay Area

A "pretty potent" atmospheric river packing heavy rain and gusty winds started battering the Bay Area late Tuesday night and is expected to continue through Wednesday and into Thursday, according to weather officials.

The latest storm to take aim at an already waterlogged Bay Area will likely lead to flooding, toppled trees, power outages, potential mudslides and other problems in some spots across the region, Meteorologist Brian Garcia with the National Weather Service said.

"It could be a nasty system," Garcia said. "The Wednesday morning commute could be pretty brutal."

The storm system has prompted authorities to issue a number of weather alerts due to the expected downpours and strong winds.

A flash flood watch has been issued between 10 p.m. Tuesday and 10 a.m. Thursday for much of the Bay Area, according to the weather service. Water levels in creeks, streams and rivers that routinely flood could rise rapidly. The deluge of rain expected to soak already saturated soil could also trigger rockslides, landslides and debris flows.

The weather service has also issued a high wind warning between 10 p.m. Tuesday and 10 a.m. Thursday for locations along the coast and in the hills sitting above 1,000 feet. Winds are predicted to blow between 25 and 35 mph, while gusts could peak around 60 mph. The weather service warned that scattered power outages should be expected.

A wind advisory has been called during the same time period for valleys located in the North Bay, East Bay and South Bay. Wind speeds could range between 20 and 35 mph, with gusts topping out around 45 mph.

NBC Bay Area’s Kris Sanchez monitors water levels at South Bay reservoirs as an atmospheric river takes aim at the Bay Area.

Between Tuesday and Thursday, locations in and around Santa Rosa and San Rafael could pick up as much as four inches of rain, according to the weather service. Napa, Half Moon Bay and Santa Cruz are predicted to collect 2 to 3 inches of rainfall. San Francisco, Concord and Fairfield are slated to receive 1.5 to 2 inches. San Jose and Livermore are expected to tally 1 to 1.5 inches.

The wet weather is expected to taper off in time for the weekend, NBC Bay Area Meteorologist Kari Hall said. It appears that Saturday will stay dry, but scattered showers could return Sunday.

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