Heaviest rain, wind expected midday today

Expect southerly winds between 32 and 46 mph this afternoon as a vigorous cold front passes through the Central Coast, bringing more heavy rain.

This is thanks to a very strong, and fast-moving low-pressure storm that developed about 400 miles west of Northern California, according to John Lindsey, communications specialist with Pacific Gas and Electric Co. and longtime Central Coast weather forecaster.

Southeasterly winds at the Diablo Canyon nuclear power plant reached 40 mph sustained earlier this morning, with gusts near 50 mph.

The heaviest rain today is expected to take place between 11 a.m. and 1 p.m., Lindsey said.

This storm could bring 1 to 3 inches of rain across most low-elevation areas, and 2 to 4 inches along coastal-facing mountains, he added.

The rain is expected to turn to showers — at times heavy — and there is a chance for thundershowers later in the afternoon, Lindsey said. This is expected to gradually taper off tonight, with scattered rain showers.

He said snow is expected to be heavy across the Sierra Nevada, with snow levels starting at 6,000 feet, and then gradually dropping to 4,000 feet or lower this afternoon.

Out in the surf, a 6-to-8 foot northwesterly (300-degree deep-water) swell (with a 20 to 22-plus second period) arrived along coastline last night and will increase to 9 to 11 feet later this morning, Lindsey said.

This swell will further build to 12 to 14 feet (with an 18-20 second period) by this afternoon.

Increasing southerly winds will produce 10 to 12 foot (180-degree shallow-water) southerly seas this afternoon, but will decrease tonight, he added.Westerly winds of nearly 60 mph on the back side of a series of fast-moving storms will blow over an 1,800-mile-long wind fetch (the distance of water over which the wind blows) out over the eastern Pacific, Lindsey said.

Mountain high wind, gale and surf warnings are still in effect, according to the National Weather Service.