La Niña

La Niña is coming this winter, but authorities aren’t expecting this to be a year of catastrophic flooding. At the same time, they told attendees at a winter storm briefing on Wednesday in Salinas, residents should be prepared for the worst. The briefing was sponsored by the Monterey County Office of Emergency Services.

The National Weather Service is forecasting a cold winter, with strong rains in December, gradually drying out in January and February.

A rare weather pattern known as a “strong La Niña” will dominate the winter’s weather, said NOAA representative Tom Evans. In previous years, strong La Niñas have coincided with historic flooding, notably in 1955 when downtown Santa Cruz was engulfed as the San Lorenzo river overflowed.

Last Thursday, the National Oceanographic Atmospheric Administration came out with its latest El Niño/La Niña-Southern Oscillation Advisory, predicting that the current La Niña will peak in the strong category and will persist until next spring.

Since 1950, there have been 19 years with La Niña conditions. In those years, rainfall in San Francisco has averaged 90 percent of normal, and in Los Angeles 80 percent of normal. During the most recent La Niña event, in 2007-08, rainfall was 79 percent of normal in San Francisco.

But it’s not a certainty that California lawns will be brown come next spring. That’s because in some La Niña years, rainfall has been more plentiful than normal. In one such year, 1999, San Francisco rainfall hit 115 percent of normal.

Nights up here have been in the 30’s for the last 3. And per one forecaster, “A few of this morning’s models are suggestion an intense storm moving into the Pacific Northwest next week with a weakening associated cold front passing over the Central Coast next Friday and Saturday with rain showers.”