Jet Stream Is Delivering 2 More Storms

The second storm in less than a week is expected to bring rain to Southern California this afternoon, and a third storm should bring more by Monday.

Today’s fast-moving storm is expected to be a lot like the one that dropped about three-quarters of an inch of rain on Los Angeles last weekend, most of it within a few hours.

National Weather Service meteorologist John Gorman said light showers could dampen parts of Los Angeles County this morning, but the body of the storm probably won’t arrive until early afternoon.

“There will be some pretty steady rain after 1 or 2 p.m., but it won’t last that long,” Gorman said. He predicted a half an inch to an inch of rain downtown, with 1 1/2 inches or more in some foothills and mountains before the storm leaves about 7 or 8 p.m.

The storm is expected to reach Orange County late this afternoon, bringing strong, gusty winds, the weather service said. The overnight low temperature in Santa Ana is expected to be 49 degrees. Friday will be partly cloudy with a daytime high temperature of 63 degrees, forecasters said.

Daytime coastal temperatures will be in the 60s, about 5 degrees below normal for this time of year, but it won’t be cold enough in the mountains for any significant snowfall at most Southern California ski resorts, the weather service said.

No rain is expected again until Monday, when the third storm system moves onshore.

“Right now, it’s too early to tell how strong that one is and how fast it will move through,” Gorman said.

High-altitude, jet stream winds are funneling the Pacific storm track directly into California, so the potential for rain next week remains high, he said.

Rainfall this fall has been about half of normal. The downtown Los Angeles total for the season, which runs from July 1 through June 30, is 1.24 inches, compared with a normal of 2.68 inches by Nov. 28.

However, the National Oceanographic and Atmospheric Administration is predicting a mild El Nino condition this winter.

During most El Nino winters, Pacific jet stream winds are intensified and extended all the way across the the ocean to California and Baja California. Large low-pressure centers over the central Pacific spin off an unusual number of storms, and the amplified jet stream tends to funnel more precipitation than usual into Southern California.

That’s what happened in the fall, winter and spring of 1997-98, when 31 inches of rain fell on downtown Los Angeles, more than twice the normal amount and the third-highest total on record.

But that was one of the strongest El Ninos ever measured, and forecasters say the one expected this winter probably won’t be as strong.