Finally, Umbrella Weather

The convergence of two moist weather systems--a warm one from the subtropical Pacific and a much cooler one from the Gulf of Alaska--is expected to bring substantial rain to a parched Southern California today.

Showers began falling in Santa Barbara and Ventura counties late Monday, and forecasters said the precipitation should become widespread by dawn, with between a half-inch and an inch of rain in the coastal valleys and about twice that much in foothill communities.

Forecasters said the showers could become locally heavy at times, with as much as 2 inches of rain falling in some isolated canyon areas. Gusty winds are expected, especially in the mountains and below canyon passes.

The precipitation is expected to taper off tonight, with the possibility of a few scattered showers Wednesday morning.

Because much of the weather has been generated over the subtropical waters of the central Pacific, temperatures will remain on the warm side, with a relatively high snow level of between 7,500 and 8,000 feet in in Southern California’s mountains.

While the precipitation will help, it probably won’t be enough to put an appreciable dent in Southern California’s prolonged dry spell.

Only 0.89 of an inch of rain has fallen on the downtown Los Angeles weather station on the USC campus since July 1, less than one-seventh of the normal season’s total for the date of 7.00 inches.

Meteorologists say you probably can pin a lot of the blame on the current La Nina--an enduring oceanographic and meteorological counterpoint to the drenching El Nino season of 1997-98.

During El Ninos, it’s usually wetter than normal in Southern California; during La Ninas, it’s usually drier.

Despite the likelihood of at least two drier-than-normal years in a row, the Southland is still a long way from a widespread drought, according to officials at the state Department of Water Resources.

As during most La Ninas, rainfall at the northern end of the state has continued to be near or above normal, and the state’s reservoirs currently stand at about 115% of normal.

Heavy rains pounded the northern half of the state on Monday, with 3 inches and more reported at a number of towns in the Sacramento Valley and along the western foothills of the Sierra Nevada.

Temperatures were much cooler in the north, where the Alaskan storm was predominant, and forecasters said 2 feet of new snow was expected at ski resort areas near Lake Tahoe.