The first of three wet-weather systems expected to roll through the Bay Area left its mark Tuesday, and it was much less notable than National Weather Service forecasters expected it to be.
They anticipate the next two will be much more significant.
“That was a bit of a letdown,” National Weather Service meteorologist Jeff Lorber said of a storm that soaked Sonoma County but left the the rest of the Bay Area with little rain. Areas of Marin County measured four-hundredths of an inch, while downtown San Francisco had .03 inches — the most rain measured outside of Sonoma County.
Santa Rosa had one of the highest rain measurements, with three-quarters of an inch measured there.
“We were expecting more like a quarter- to a half-inch” in the areas of Contra Costa, Alameda and Santa Clara counties, Lorber said. “We’ll still get some light showers through (Wednesday) morning, and there may be a heavier push in the afternoon.”
The heaviest storm is still days away, Lorber said. An atmospheric river — a narrow storm with a lot of moisture — was deemed a Category 5 system Tuesday, the highest level possible. That storm is expected to hit Sunday night and carry into Monday, Lorber said.
“There is still some uncertainty of where the moisture is going to line up exactly,” Lorber said. “But we are expecting at least over an inch and possibly as much as five inches in some places, depending on the path it takes. That’s going to be a widespread rainfall event.”
The precursor to that system is another one that’s expected to push through the region late Thursday into Friday morning, Lorber said. Again, the North Bay will see the bulk of that rain — Lorber said some areas of the North Bay are predicted to receive up to 2 inches — but the central region and South Bay also are likely to get at least a quarter-inch and as much as a half-inch, according to forecasters.
That event also has the look of an atmospheric river, forecasters said, though not as powerful as the one expected to arrive Sunday.
Fire officials and forecasters are hopeful that the three storms may drastically reduce fire danger throughout Northern California, even as they could create mudslide problems in areas where flames have ripped through vegetation in recent weeks.
Areas near the Dixie Fire in Mount Lassen and the Caldor Fire in South Lake Tahoe are particularly vulnerable, officials said.
Staff writer Paul Rogers contributed to this story.