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And on the 54th day, it rained.

That's the forecast anyway. So advised the National Weather Service, which says the light drizzle throughout the Bay Area early Wednesday was an appetizer for an appearance by rain drops for the first time since early December later Wednesday night or early Thursday morning.

But think again before taking this as a signal that the heavens are about to open up.

"It might bring a quarter-inch to the North Bay, maybe one-tenth of an inch in the East Bay," forecaster Steve Anderson said. "It's not going to make a dent in any water deficit."

Nevertheless, the drizzle broke the monotony of bone-dry days and nights, which Anderson said is the result of a thick, high-pressure system surrounding California and other parts of the West Coast that has sent most weather systems up to Alaska.

On Wednesday, a small system pushed its way through, scattering light rain on nearly every part of the Bay Area. It began just after midnight and carried through the morning commute, wetting the roadways but not much else, Anderson said.

But the drizzle is expected to be replaced by rain coming from a system that will reach the North Bay around 10 p.m. and then impact Santa Clara, Alameda and Contra Costa counties around midnight, Anderson said.

"The size of the drops coming down is the difference," Anderson said. "The drizzle was heavy enough to create the wet roadways, but it didn't create much more than that. The rain we get tonight will be more significant but again, it's not going to rain a whole lot."

The state of California is in desperate need of whatever precipitation it can get. State officials said Tuesday that 17 communities across the state are in danger of running out of water in 60 to 120 days. The water systems, all in rural areas, serve from 39 to 11,000 residents and range from the tiny Lompico County Water District in Santa Cruz County to districts that serve Healdsburg and Cloverdale in Sonoma County.

Anderson said that save for a brief period of drizzle in San Francisco two weeks ago, the drizzle that fell Wednesday was the first precipitation in the Bay Area since Dec. 6, a stretch of 53 days. The drought has been billed as the driest period in the state's recorded rainfall history.

The rain won't last, Anderson said. The system bringing the rain may last through Thursday, he said, but will have moved out by Friday, and no rain is expected in any of the long-term forecasts.

Temperatures also are expected to remain warmer than normal for the foreseeable future, Anderson said.

Staff writer Paul Rogers contributed to this story. Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH. Follow Paul Rogers at Twitter.com/PaulRogersSJMN.