More rain heading to San Mateo County

Get ready for more soggy socks. 

While the massive storm through this weekend almost broke single-day rain records, the National Weather Service forecast shows more rain, more floods and strong winds in the coming weeks.

From last Thursday to Sunday, Spring Valley Ridge on Montara mountain saw 9 inches of rain. Pacifica accumulated 5-6 inches of rain. On the Bayside, San Francisco International Airport reached 4.62 and Redwood City reached 5.12 inches. National Weather Service meteorologist Rick Canepa said it was an impressive amount of rain.

“We’re not out of the drought yet but this is adding a lot of surplus in a hurry and so we will see what our numbers are like later in the month,” Canepa said.

Canepa said New Year’s Eve’s 4.47 inches of rain in the county is the third highest amount of rain in a single day. The most rain in a single day was 4.88 inches in 1962. The water year, which is from Oct. 1 to Sept. 30, is how the NWS gauges rain compared to previous years. So far this year, from Oct. 1 to Jan. 2, the county has seen 12.2 inches of rain. That is 177% more than the average, calculated from the previous 30 years.

However, Canepa warns there is still more to come. An atmospheric river, also known as a Pineapple Express system, is headed toward the Bay Area and will arrive on Wednesday morning, bringing 2 1/2 inches of rain to Redwood City. They are known as Pineapple Express systems since they build up in the tropical Pacific Ocean and build up steam through Hawaii, bringing heavy rain and potential snow to the West Coast of the United States and Canada.

“The jet stream spans across the entire Pacific and the water that gets caught up in that system is from Hawaii, Guam and the Philippines,” Canepa said.

The NWS issued a flood and wind advisory from Wednesday morning to Thursday night, Canepa said. Wednesday morning’s winds could reach up to 50 mph. The rain is anticipated to continue through Thursday into the weekend. On Saturday, the Bay Area could receive more than an inch of rain.

Another storm system will reach the county on Monday, Jan. 9. Canepa said this particular system is moving slower, meaning it will rain more, so it could add another 3 to 3 1/2 inches of rain.

So far, it looks like January will be wetter than normal this year. The county could accumulate more than 8 inches of rain by Jan. 10, Canepa said. In comparison, normal monthly rain totals for January average 3.81 inches.

Megan McFarland, spokesperson for Pacific Gas and Electric, said the New Year’s Eve storm delivered heavy rain to its service area with water levels resulting in flooding, landslides, road closures and power outages in some areas.

“Our focus today [Monday] is assessing damage and making needed repairs to restore power to the remaining customers affected by the storm,” McFarland said.

PG&E has 1,300 personnel on storm duty, with mutual-aid crews arriving on Monday from Southern California Edison focused on restoration. On Monday, about 1,500 customers were without power in San Mateo from 10 a.m. to noon, due to the storm, McFarland said in an email.

Last week’s storm caused major flooding in most cities around the county. Some of the worst cases were in San Carlos, San Mateo and South San Francisco.

McFarland said PG&E is pre-staging power poles, power lines, transformers and other electric equipment at yards throughout its service territory to restore power to affected areas safely and quickly. Its vegetation management crew is working to keep trees away from power lines to reduce the risk of outages caused by downed trees.

“PG&E uses its storm outage prediction models that help determine the potential timing, location and number of power outages. This allows us to have extra crews on standby to deploy to areas that are hard hit by the storm,” McFarland said in the email.

Throughout the rest of the week, temperatures should be fairly consistent with lows in the upper 40s and highs in the upper 50s.

NWS suggests residents should monitor the latest forecasts and warnings for updates on wind situations. Fasten loose objects or shelter objects in a safe location prior to the onset of winds. Residents should have an emergency kit with water, blankets, flashlights, batteries and snacks in case they experience a power outage. Those living in areas prone to flooding should be prepared to take action should flooding develop. Check with county and city websites to find information about sandbag locations.

Visit weather.gov/mtr for more information from the National Weather Service.