Back-to-back storms are expected to drop an inch of rain on the Bay Area this weekend, which has Daly City residents nervously watching the hillside gouged open by this week's massive water leak.

Forecasters have predicted a storm on Friday and another on Sunday will each drop a half inch of rain on the region, including the Lausanne Avenue neighborhood left stuck in mud but mostly undamaged by the leakTuesday.

The first storm will be heaviest during Friday evening's commute and then should taper off, National Weather Service forecaster Steve Anderson said. After scattered showers Saturday, a second storm will roll in overnight or early Sunday.

Daly City residents are worried the umbrella weather could provoke another mudslide from the hill left that already has a gash that's roughly 200 feet long and up to 40 foot deep after the city water pipe ruptured. Officials on Thursday revised the estimate of water that leaked up to 97,835 gallons from an earlier estimate of 45,000 gallons.

As part of their plan to keep mud from again filling up the streets and enveloping residents' cars, crews have uncovered a 24-inch storm drain in Hillside Park, which partially disappeared under the flowing mud. Crews have connected the gouged hillside and the drain with a ditch.

The idea is to get the rain run off into the drain and out of the neighborhood, Daly City sewer and water director Patrick Sweetland said. But crews will be on standby just in case. He said city workers are expected to check on the drain if rain falls continuously for more than 30 minutes.

"This is not a set it and forget it operation," he added.

The leak estimate more than doubled Thursday because officials, for the first time, included over 57,000 gallons which was being pumped up the hill into a storage tank but spilled due to the 8-inch pipe rupture. The prior estimate included only the water that escaped from the tank.

Contact Joshua Melvin at 650-348-4335. Follow him at Twitter.com/melvinreport.