Despite the recent rain in The City and on the Peninsula, residents should not begin building their arks just yet.
Meteorologists with the National Weather Service said the rains — the first throes of La Niña — are no indication that this winter will be especially wet despite the scarcity of any significant precipitation before this month.
Already this month — typically the best weather of the year — downtown San Francisco has received 1.86 inches of rain while San Francisco International Airport has seen 1.95 inches. Both totals are more than 20 percent of 2007’s year-to-date accumulation, according to the National Weather Service.
Last year in the month ofOctober, the same areas received .33 inches and .63 inches of rain, respectively.
But despite the increase, “this is not an indication it’s going to be a wet winter,” said Will Pi, meteorologist with the National Weather Service.
For that reason, it is “absolutely essential” that Bay Area residents continue to limit water usage, San Francisco Public Utilities Commission spokesman Tony Winnicker said.
The SFPUC operates the Hetch Hetchy water system, which delivers drinking water to the Peninsula and The City. Winnicker said Crystal Springs Reservoir in San Mateo County is at 60 percent capacity while Hetch Hetchy is at 70 percent, both low for this time of year.
Conservation methods taken by Bay Area residents have, however, alleviated some of the pressure from this year’s lack of rainfall, he said. And any new rain is welcome.
The rains are a byproduct of the weather phenomenon known as La Niña, Pi said. La Niña and its cooler-than-normal sea-surface temperatures typically bring more precipitation to Northern California and drier conditions to Southern California. Its counterpart, El Niño, means warmer sea-surface temperatures and brings the opposite conditions to the area, he said.
Pi said La Niña could mean more snowfall than normal in the Sierra Nevada mountains.