Bay Area forecast: Atmospheric river brings heavy rain, strong winds

More rain is on its way to the Bay Area in the form of an atmospheric river, bringing heavy downpours and strong winds starting Friday evening into Saturday.

The powerful storm has prompted a number of weather alerts issued for various parts of the Bay Area, including a flood watch, a coastal flood advisory, a high wind warning, a wind advisory and a high surf advisory, according to the National Weather Service. Check the weather alerts page for specific alerts and their timeframes in each region.

Rain timeline

The atmospheric river system is forecasted to arrive late Friday into Saturday, bringing up to 3 inches of rain and wind gusts of up to 40-50 mph at higher elevations and along the coast, weather officials said.

There should be a lull in the rain Sunday but more wet weather is expected to arrive on Monday, according to the weather service.

Flood watch

A flood watch has been issued from Friday afternoon through Sunday afternoon for the North Bay interior valleys. The weather service says excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations, including in urban areas.

Coastal flood advisory

The National Weather Service issued a coastal flood advisory that started Thursday morning and remains in effect until 1 p.m. Monday along the San Francisco and San Pablo bays.

Here's a breakdown of the advisory from NWS:

• Tidal levels are increasing as a result of higher astronomical tides.
• Low lying areas within the San Francisco Bay Area may see minor flooding as a result during high tide.
• San Francisco highest tides are expected to be 6.74 feet at 8:12 a.m Thursday, 6.98 feet at 8:54 a.m. Friday, 7.07 feet at 9:37 a.m. Saturday, 7.02 feet at 10:22 a.m. Sunday, and 6.82 feet at 11:08 am Monday.

High wind warning

A high wind warning has been issued for San Francisco and the Peninsula coast from 10 p.m. Friday until 7 a.m. Saturday. South winds are expected at 20-30 mph, with gusts up to 50 mph, which could result in blown down trees and power lines as well as widespread power outages, the weather service said.

Wind advisory

A wind advisory has been issued for the entire Bay Area, starting at various times Friday depending on the region and lasting until Saturday morning.

High surf advisory

A high surf advisory has been issued for San Francisco and the Peninsula coast from 10 p.m. Friday to 7 p.m. Saturday, according to the National Weather Service.

"This is just the start of hazardous conditions that will be expected into next week," the National Weather Service's Bay Area bureau said on social media. "Please exercise extreme caution on the water and at the beach."

Use interactive radar to track the rain

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Bay City News contributed to this report.