SAN FRANCISCO (KRON) — A Flood Advisory remains for San Francisco and BART is warning of delays, even as the heaviest rain falling on the Bay Area begins to give way to more intermittent showers. Heavy downpours arrived overnight Monday into Tuesday and continued through the morning. Across the Bay Area, the storm has downed trees, snarled traffic, wreaked havoc on the commute and prompted flood advisories for some areas. By dawn, San Francisco had already received more than an inch of rain.

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10:11 a.m. — BART delays of up to 20 minutes possible

BART is warning riders there could be possible systemwide delays of up to 20 minutes due to wet weather conditions. “Please watch your step on wet platforms and stairways,” the transit system tweeted.

9:30 a.m. — Power restored on Treasure Island

Power has been restored to Treasure Island following an earlier outage, according to an automated message from the SF Public Utilities Commission. An advisory that power was out on the island had been sent out at 7:35 a.m. Residual traffic delays are expected in the area, according to the SF Dept. of Emergency Services.

8:10 a.m. — Flood advisory issued for San Francisco

The NWS Bay Area has issued a Flood Advisory for San Francisco that is in effect until 2 p.m., according to the SF Dept. of Emergency Services. There is also a Flood Watch in effect until 4 p.m., and a Wind Advisory in effect until 9 a.m. A High Surf Advisory is also in effect until 9 a.m. Wednesday. Free sandbags are available from SF Public Works at Main and Kansas Streets, just off Cesar Chavez.

8:05 a.m. — Hail possible in North Bay

Pea sized hail is possible in Santa Rosa, Petaluma and San Rafael, according to a Special Weather Statement issued by the NWS. The statement also advised of 40 mph winds and urged residents to seek shelter indoors. The advisory is in effect until 8:15 a.m. Tuesday.

8:00 a.m. — Power outage reported on Treasure Island

A power outage has been reported on Treasure Island, according to an alert from the San Francisco Public Utilities Commission. The advisory was issued at 7:35 a.m. Crews are working to restore the power.

7:54 a.m. — Hail possible in some areas, NWS says

Pea sized hail is possible in Daly City, San Mateo and Redwood City, according to the National Weather Services. The NWS has issued a Special Weather Statement for those cities advising of possible hail and winds up to 40 mph. Residents are urged to seek shelter in a sturdy structure. The advisory is in effect until 8 a.m. Tuesday.

7:45 a.m. — Lightning reported in North Bay

There have been reports of lightning near Lake Sonoma in Geyserville, according to a tweet from the National Weather Service. “Remember to stay safe. When thunder roars, go indoors!” the tweet read.

7:40 a.m. — Winter Storm Warnings issued for Sierra Nevadas

The first in a week of storms brought gusty winds, rain and snow to California on Tuesday, starting in the north and spreading southward.

Winter storm warnings were issued for the Sierra Nevada, where motorists were advised that the combination of winds and snow could make travel hazardous.

The greater Lake Tahoe area and Mono County were warned to expect heavy snow with wind gusts around 50 mph (80 kph), and up to 100 mph (161 kph) along Sierra ridgetops. Lake Tahoe was expected to have waves that could capsize small vessels.

7:25 a.m. — Special Weather Statement issued for San Francisco, Vallejo and Berkeley

A Special Weather Statement has been issued for San Francisco, Vallejo and Berkeley, according to a tweet from the NWS. Threat information includes 30 mph winds and residents are advised to seek shelter in a sturdy structure. The statement is valid until 7:45 a.m. Tuesday.

7:12 a.m. — Radar Update from NWS

The back edge of the storm front is passing San Francisco but the rest of the South Bay and Central Coast are still under the rain, according to a tweet from the National Weather Service Bay Area. Notable clearing has begun in the North Bay, but showers are expected to continue through the morning, according to the NWS.

6:18 a.m. — Tree downed on Eastbound Highway 4 in Pittsburg

A downed tree on the Eastbound lanes of Highway 4 west of Railroad Avenue in Pittsburg is blocking the center and right lanes, according to a tweet from 511SF Bay.

5:46 a.m. — BART advises of delays due to weather

There may be systemwide delays of up to 10 minutes due to wet weather this morning, BART advised in a tweet. “Please watch your step on wet platforms and stairways,” the tweet warned.

5:43 a.m. — Tree down at Franklin and Geary in San Francisco

Photo: Sara Stinson

5:30 a.m. — Flood advisory in effect for North Bay

The National Weather Service forecast for Tuesday for the San Francisco Bay area calls for rain and showers, with highs in the low 60s. There is a flood advisory in effect for parts of the North Bay and coastal areas.

The heavy morning rain and strong winds will give way to spotty showers mid-day and the chance of thunderstorms. Skies generally grow clearer and dryer into the afternoon. Highs today will be in the upper 50s to low 60s. We will get a break from rainfall tomorrow before more rain Thursday, Friday and Saturday to finish out the year.

Bay City News contributed to this report.