Storm set to soak SLO County on Friday

A new rain storm is expected to roll into San Luis Obispo County on Friday, but while it will bring a nice soaking, it isn’t packing the heavier rain that forecasters once expected.

Local forecasting expert John Lindsey and the National Weather Service agree that rainfall should start across the county Friday afternoon and continue overnight. Showers will linger into Saturday afternoon, and then conditions will start to dry out.

Lindsey, a community relations specialist for PG&E, said Wednesday that the storm should dump from a half-inch to an inch of rain on San Luis Obispo. Amounts in the coastal mountains will range from an inch to 1.75 inches.

That's in contrast to his prediction the day before, when up to 1.75 inches were to fall in coastal valleys and up to 3 inches in the mountains.

The storm started weakening Wednesday, Lindsey said, and much of its energy could stay offshore. “It will be a nice rain — we definitely need it — but it should not cause any problems,” said Lindsey, who has more than 20 years of local forecasting experience.

One challenge in forecasting the storm lies in how it is partially cut off from the main storm track along the coast, Lindsey said. When a low-pressure system becomes cut off, it can act independently and thus is harder to predict.

In its forecast, the National Weather Service said there is “the amazingly large variance in possibilities that exists with this storm.”

The high temperature today will be in the 70s in Paso Robles and San Luis Obispo, then cool into the 60s through Sunday. Overnight lows will be in the 40s and 50s.

Wine-grape harvest update

In preparation of the coming storm, Central Coast wine-grape growers are working to get any remaining fruit off the vine. “We’re looking to get it all off by Friday,” said Doug Filipponi of the Atascadero-based vineyard management company Filipponi & Thompson, which oversees 1,600 acres in Paso Robles. Filipponi says early freezes reduced much of this year’s vintage. Untimely rains and spring frosts set back ripening in area vineyards about three weeks.

“It’s a little too late to be concerned about rain now. Most everything is in the barrel or in the tank now,” said Filipponi. His company grows several different varieties of grapes like grenache, refosco, mourvedre and cabernet.

Thick skinned cabernet grapes can stay on the vine the longest. But Filipponi says even those will be picked by Friday. “I’m going to call it an end to the 2011 season,” said Filipponi. With more than 20 years of experience growing wine grapes, Filipponi says 2011 “has been by far the most difficult. The weather this year has been pretty traumatic.”

Picking is near an end in the Edna Valley, too. “We’re almost done picking now,” said Fin du Fresne, winemaker for Chamisal Vineyards in Edna Valley. “The last pick is (today). We figured the vines had enough rain and with the colder temperatures, there’s no reason to leave the grapes on the vine.”

County grape growers say after several wet-weather harvests, they’re learning to deal with uncooperative conditions. “The thing about 2010 is we never thought we’d see another year like that, and then we did — 2011,” du Fresne said.