SAN FRANCISCO (CBS SF/AP) — Rain and wind Tuesday night into Wednesday morning will be particularly heavy in Santa Cruz and Monterey counties, potentially causing flooding in some of the burned areas there, a National Weather Service meteorologist said.
Most of the rain will hit the mountainous areas of Santa Cruz and Monterey counties, where up to 5 to 8 inches of rain could fall over a 12-hour period starting late Tuesday night.
Rainfall could be so heavy that up to an inch an hour could fall Tuesday night, weather service meteorologist Brian Garcia said.
That could lead to flash floods and debris flowing out of some of the areas that burned over the summer, such as the Loma Prieta area of the Santa Cruz Mountains and the sites of the Soberanes and Chimney fires in Monterey County, Garcia said. The debris could flow onto and block roadways.
At about 12 p.m. Tuesday, the National Weather Service issued a Flash Flood Watch for the Santa Cruz Mountains.
The watch will start at 7 p.m. Tuesday evening and will extend through Wednesday morning. Rainfall rates in excess of 3/4 of an inch inch per hour are possible during that time period.
It is during these heavy downpours that flash flooding is most likely to occur.
Heavy rain could also fall in Napa and Sonoma counties, where in some areas up to 4 inches of rain could fall, potentially leading to some flooding.
Another larger rainstorm is forecast for this weekend, when as much as 5 to 7 inches of rain could fall in San Francisco. There will be some rain Friday night, but most of the rainfall will be between Saturday night and Sunday morning, according to Garcia.
As of 8 p.m. Tuesday, PG&E was reporting approximately 10,000 customers dealing with weather-related power outages.
The new year started off with a sprinkling of snow on Bay Area peaks Tuesday morning to start what is shaping up to be a full week of cool and wet weather throughout the region.
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Forecasters say a winter storm advisory is in effect until 4 a.m. Wednesday at the lower levels. A winter storm warning will be in effect above 4,500 feet until 4 a.m. Thursday.
National Weather Service Forecaster Bob Benjamin says four to five feet of snow is expected above 5,000 feet Tuesday.
A wind advisory was also in effect starting Tuesday afternoon until 1 a.m. Wednesday morning for the entire San Francisco and Monterey Bay region. Some urban locations could experience southerly winds 20 to 30 mph with local gusts to 45 mph.
Despite the high winds, downed trees are the least of concerns for neighbors in Alviso in North San Jose. Alviso sits below sea level.
In years, past the neighborhood’s electric pumps have failed, causing flooding problems.
The city says it spent last year testing the electric pumps in Alviso in anticipation of El Niño storms, which they now say could work in their favor.
But the storms may put a halt to public projects including sewer work for days.
The weather was also having an impact on air travel plans. So far Tuesday, there were 70 flight cancellations. Weather-related delays were averaging 60 to 90 minutes.
While the more persistent moderate-to-heavy rainfall will gradually diminish from north to south late Tuesday night into Wednesday morning, lingering precipitation will remain possible region-wide through Wednesday night.
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