Atmospheric River To Hit Walnut Creek This Weekend: Weather Service

WALNUT CREEK, CA — December is off to a chilly and blustery start this year in Northern California. More turbulent weather is anticipated this week, and residents can expect heavy rain, strong winds and thunderstorms over the weekend, the National Weather Service announced.

The first of two storms will hit Thursday before a more powerful atmospheric river arrives Friday to soak the weekend. Weather officials said Saturday will likely be the most intense day of the storm, and minor flooding could impact drivers.

In Walnut Creek, the rain will likely continue through Sunday, according to AccuWeather. A brief respite from the rain is expected during the day Friday. Showers are forecast to arrive Friday evening, followed by heavy rain and the possibility of thunderstorms Saturday, forecasters said.

Through Friday, the expected rainfall is .2 -.5 inches in the East Bay, San Francisco and the rest of the Bay Area, .5 - .75 inches for the North Bay, and .1 - .25 in the Monterey Bay region, the weather service said. In the Santa Cruz Mountains, .5 - .75 inches are expected. One - 1.25 inches of rain is expected in the coastal mountains, officials said.

Rain is expected to pound the region on Saturday, with the North Bay forecast to get 2-5 inches of rain. The East Bay and the rest of the Bay Area will likely get 1-2.5 inches of rain Saturday.

Storm No. 2 is shaping up to be in the "weak Atmospheric River category," the National Weather Service said Thursday. The rainfall outlook has the entire coastal area at a marginal risk for flooding on Saturday, with a brief increase in stream flows on area creeks and streams. No main stem river issues are expected, but a rise in some rivers will be possible.

"Similar to the last weak [Atmospheric River] some ponding on roads and minor nuisance flooding is possible," NWS said. "Rainfall amounts 2-4 inches with a jackpot of 5 inches for North Bay and Coastal Mountains with 1-2.5 inches elsewhere from Friday night through Sunday."

A wind advisory is expected to be in effect for much of the East Bay, including Walnut Creek, from 2 a.m. Saturday until 3 p.m. Saturday. Winds of around 15 to 30 mph are expected to whip through most communities Saturday, with gusts of up to 60 mph possible in higher elevations.

Lighter rain is expected Sunday, with frigid and dry conditions to follow throughout next week.