A major pattern change toward wetter weather is on the horizon.
After a relatively dry February, the first weekend of March is projected to get off to a wet start with possibly 1 to 3 inches of rain in the valley and heavy snow in the Sierras.
A series of weather systems are expected to arrive this weekend, possibly as early as this afternoon. Another storm on Saturday should bring heavier rain and gusty winds, according to the National Weather Service.
Snow levels will lower Saturday with moderate snowfall expected in the Sierra overnight. Rain and snow showers should extend into Sunday, with a threat of thunderstorms over the central valley.
The National Weather Service also suggests periodic storms are likely to continue through at least mid-March.
“The valley will see between 1-2 inches in the southern Sacramento Valley to 3-4 inches on the northern end of the valley from tonight through Monday morning,” said Michelle Mead, a Warning Coordination Meteorologist for the National Weather Service in Sacramento. “A majority of the rain will fall Saturday afternoon/night as a strong storm system moves through.”
Impacts of this storm, according to the National Weather Service, include:
- Urban and small stream flooding possible
- Downed trees and power outages possible
- Potential for debris flows near recently burned areas this weekend
- Potential for rock slides along mountain roads
- Chain controls and hazardous travel likely over the mountains
- Small hail and dangerous lightning with thunderstorms
Prepare for this weekend’s storms with helpful tips from Be Storm Ready.
“This is the strongest system we’ve seen since the end of January,” Mead said.
Light rain is expected today in Southern California, with a more significant amount beginning Saturday. Rain could also impact the Monday morning commute.
Snow levels may lower to around 4000 feet by Monday afternoon, likely resulting in snow on the I-5 near Grapevine.
The statewide snowpack, a source of much of the state’s water supply, is only 83 percent of the March 1 average, the Department of Water Resources (DWR) reported. DWR conducted a snowpack survey at Philips Station off Highway 50 in the Sierras about 90 miles east of Sacramento.
Snowpack conditions can be viewed here.
“This storm will help make up some of what was lost during the dry February, but we still have a long way to go,” said Mead. “Conservation is still the message to convey.”
DWR finalized a Drought Contingency Plan on Jan. 19 outlining the State Water Project and Central Valley Project operations for February-November 2016. The plan was developed in coordination with staff from state and federal agencies, including the U.S. Fish and Wildlife Service, National Marine Fisheries Service, California Department of Fish and Wildlife, and the State Water Resources Control Board (SWB). It focuses on water project operations as related to SWB Water Rights Decision-1641 and the potential modification requests needed to balance the competing needs and benefits of limited water supplies in the context of consecutive dry years.
California is still in the midst of a historic drought of four-plus years.
The most significant statewide droughts occurred during 1928-34, 1976-77, 1987-92 and 2007-09. The last significant regional drought occurred in parts of Southern California in 1999-2002.
The Drought Contingency Plan can be read here.
“The good news is some of the readings are the best for early March since 2011 but that is not necessarily indicative of the entire mountain snowpack,” said Lauren Bisnett, an Information Officer in the DWR Sustainable Groundwater Management Program. “The statewide readings suggest this may not be a drought-busting year unless California receives heavy rain this month as it did during the ‘March Miracles’ of 1991 and 1995.”
At least one of these three things, according to Bisnett, still needs to happen in order for the drought to be at an end:
- Statewide reservoir storage would need to be at 90 percent of average levels
- Runoff forecasts for the state’s water year, which runs October to September, would need to be 110 percent of average
- Reservoirs on the four major rivers in the Sacramento River basin would have to reach flood control stage
Most of the state’s major reservoirs still hold much less than their historical averages for early February. On average, 75 percent of California’s annual precipitation occurs from November through March, with 50 percent occurring from December through February.
“We’re in a position better than last year, but still way below what would be considered adequate for any reasonable level of recovery at this point,” said Bisnett, adding. “The greater the snowpack content, the greater the likelihood California’s reservoirs will receive ample runoff as the snowpack melts to meets the state’s water demand in the summer and fall. We’re hopeful as it will likely bring heavy precipitation and heavy mountain snow, but as you know, things are subject to change with Mother Nature.”