More Rain Forecast for Atlantic, Gulf Coasts : Milder Winter Predicted for Southland

Southern California can expect its weather to be milder and no wetter than usual this winter, the National Weather Service predicted in its seasonal forecast Friday, while above-average rainfall is likely on the Atlantic and Gulf coasts and below-average cold is foreseen for the Mississippi Valley.

Donald L. Gilman, long-range forecaster for the National Weather Service, said the 90-day outlook for December through February indicated a 60-40 chance of above-normal temperatures west of the Rockies in an area covering California, Nevada and Utah, most of Arizona and parts of Montana, Idaho, Washington and Oregon. Average winter temperatures in Los Angeles are in the mid-50s.

At the same time, Gilman said, chances are even that precipitation in Southern California will follow normal patterns. Rainfall in Los Angeles averages three inches in December, two inches in January and 2.8 inches in February, weather service records show.

There is a 55% to 60% chance of below-median rainfall in a belt extending from Central California northeast into Nevada, Idaho, Montana, western Utah and eastern Washington state and Oregon, Gilman said. He foresaw a 50-50 chance of snow or rain in most of the nation’s midsection, in Southern California and in the Pacific Northwest.

The weather service forecast indicated below-normal temperatures for 10 South-Central states, centering on Arkansas and extending south into western Louisiana and eastern Texas and north to parts of Iowa, Illinois and Indiana.

Gilman estimated that chances are 60 to 40 that precipitation will be above normal in a great arc extending from the Great Lakes to New England, down the Atlantic Coast to Florida, then west along the Gulf Coast to southern Texas and New Mexico and on to southeastern Arizona.

What this means, he said, is that “if we are at all right, the Southeastern drought will be essentially washed out this winter.”

Gilman emphasized that long-range forecasting is based on analysis of shifting conditions. The predictions for the winter ahead were based on statistical evidence of winds and barometric pressure above the Western Hemisphere and estimates of the effects on weather of increases of 1 to 3 degrees in the temperature of surface water in the Pacific.