Several strong weather systems will move through Northern California Thursday through Tuesday, March 15, bringing heavy rain and heavy snow, according to the National Weather Service.
Breezy to locally gusty winds are possible Thursday and this weekend.
"The upcoming wet pattern might result in increased runoff from heavy rain, leading to rises on many Northern California streams, rivers, and weir flows," says the forecast. "Thus, low land, urban, and small stream flooding are likely. In addition, heavy snow combined with wind, will likely result in hazardous mountain travel and road closures."
"Saturated soils and swollen small creeks and streams from recent rains have primed the area for potential flooding with the approaching storms," according to the NWS. "The series of storms will bring periods of moderate to heavy rainfall Thursday through early next week."
The Flood Watch covers the following counties: Amador, Butte, Calaveras, Colusa, El Dorado, Glenn, Lake, Nevada, Placer, Sacramento, San Joaquin, Shasta, Solano, Stanislaus, Sutter, Tehama, Tuolumne, Yolo, and Yuba.
The NWS says urban and small stream flooding is possible through early next week in the same counties.
"Excessive rainfall on already saturated soils and swollen small creeks and streams will likely result in flooding over the next several days," the NWS says.
"Impacts include: Rises on mainstem rivers including overflow into the Butte Sink and the Sutter Bypass. Also, low land flooding will impact any outdoor activities. Small creeks will be running high and fast, avoid playing or working near them. Ponding of water on area roadways will create travel hazards at times."
The National Weather Service also says water levels will rise on several rivers in northern California, including the Lower and Upper Sacramento River.
"Rainfall from last weekend’s system combined with more wet weather in the coming days will result in increased inflow into the Lower and Upper Sacramento River," according to the forecast.
Several locations are forecast to hit monitor stage in the coming days as storms bring more rain.
"Weir flows have decreased but are expected to flow again this weekend," the forecast says. "In addition, Tisdale Weir is already overflowing."
The snow water equivalent in the Sierra Nevada snowpack had been increasing with storms in December 2015 and January 2016. But a dry February saw the snowpack diminish.
So far, March has added to the snowpack, which is significantly improved from last year at this time. State officials are hoping a 'Miracle March' will improve snow and reservoir levels.
Water Releases From Folsom Lake
The U.S. Bureau of Reclamation is releasing water this week into the lower American River to meet flood space requirements at Folsom Lake.
After recent storms, Folsom Lake is at 124 percent of its historical average and 72 percent of capacity.
He says the bureau is monitoring the weather and will increase releases from Folsom Lake as needed.
"Right now the precipitation forecasts call for up to 7 inches of new water in the basin over the next six days, so that could be quite a bit of inflow into the lake," says Hunt.
Hunt says not releasing the water now is not an option.
"The risk is that we would have to release significantly more water than we're releasing now and that just causes potential issues downstream,” says Hunt. "We've got to make sure we stay in capacity of the levees and you know, try not to flood out the American River Parkway."
He says with the water releases, people in or along the American River downstream of Folsom and Nimbus dams should be cautious if they're in or near the river.