Update: Tree branch topples on BART tracks in San Francisco; Waterspout warning off Santa Cruz

SAN FRANCISCO -- A massive tree branch, possibly weakened during several days of stormy weather, toppled onto the BART lines in San Francisco Monday morning, disrupting service for about an hour between the Balboa and Daly City stations.

Crews rushed to the scene and were able to clear the branch by 9:20 a.m. Transit officials warned commuters to expect some minor delays.

The incident came as a slow moving weather front continued to send waves of strong storm cells spiraling over the Bay Area, triggering warnings of possible waterspouts, hail and high surf along the coast.

The system has pretty much been parked offshore since moving down the coast from the Northwest on Friday.  A weak atmospheric river fueled by the front dumped 5 inches or more along the mountains in Monterey County and several inches elsewhere.

"There's still a lot of energy off the coast," said KPIX meteorologist Darren Peck. "On again, off again scattered showers. There will be more times you're not getting rained on then when you are."

On Monday morning two strong storm cells roll through the Bay Area. On band moving through Sonoma and Mendocino counties was triggering downpours and lightning.

 A second cell slammed into the coastline from Davenport to Capitola, triggering weather and marine advisories warning of possible small hail, waterspouts and high surf.

Forecasters said the downpours will decrease in intensity during the day.

"Isolated rain showers will continue through the day lasting through Tuesday morning," the weather service said. "An additional 0.3-0.5 inches is expected around the Bay Area through tomorrow morning, with locally higher amounts over favored coastal terrain which could get up to another 0.75 inches."

Breaks in the showers should have crews clearing a rockslide that has blocked Highway 1. Both directions of the highway were closed over the weekend from south of Big Sur to Ragged Point in San Luis Obispo County.

Caltrans officials said the storm damage assessments on Sunday revealed dozens of areas of concern which range from rocks and debris on the roadway throughout sections of the entire length of the closure area.