I poked around some of the winery websites in the area and the consensus about Harvest 2010 so far is that it's behind "normal". At Clos La Chance, they are running about a week behind in veraison and anticipate the first grapes coming to crush in another week or so.
For Stefania Wine, the vineyards we manage in Morgan Hill and Los Altos Hills are on track, but running about two weeks past "normal". The grapes at the "estate" (our suburban home in South San Jose) vineyard are also about two weeks behind normal. The fruit we have growing in Woodside still has not yet started veraison. The cabernet sauvignon is likely a loss this year, or we harvest in December...it's too soon to tell for sure.
Some of the other high altitude vineyards are reporting similar conditions and much of it has to do with the weather. The very wet winter was fabulous for the roots and quenched the vines from the past few drought years, but then the cool Spring got everything off to a very slow start. It would be great for everyone, tomato growers too, if we had some very warm days all through September and October.
Historically we have a cooling trend and sprinkles around the 1st and 2nd weekends in October so we'll see what impact that has on ripening this year.