California winemakers have always prided themselves—often arrogantly—on the fact that they can harvest whenever they want to. That is, unlike the wine regions of continental northern Europe, which have real seasons and are subject to the cold and rain that September often brings, California enjoys a long, warm, dry Indian summer lasting usually through to the end of October. Thus, European winemakers often find their (crucial) picking decisions dictated to them by rain storms, while California winemakers can choose to harvest their grapes whenever they please.

But now there's a massive storm dropping inches of rain on all those happy California vineyards, threatening the weather that wine writers were already licking their chops about ("2009 Harvest Is Shaping Up to be Memorable" and "'Perfect' growing season for grapes leads to optimism").  It's not a problem for early grapes like Chardonnay and Pinot, but there's still lots of Syrah and Cabernet hanging out on the vines.

Worried winemakers are tweeting up a storm, themselves:

"Trucks with grapes are grinding traffic to a stop in Napa and on the back roads of Sonoma. Everyone is scrambling to pick before the rains."

"With storm looming, Central Coast growers hustle around the clock to bring in the wine grape harvest."

"Movin' machinery for night #harvest, hunkerin' down for rain. 'Bout to close out the season with a storm."

"Storm clouds gathering. Wonder whose grapes aren't in yet."

The funny thing is that I think California's lax fall climate encourages winemakers to let the grapes sit out too long, becoming overripe, raisined and jammy. Many growers in Napa have grapes still on the vine that are already at 26 to 27 brix (meaning wines over 15% alcohol—too high in my book). Why let them ripen longer? They're just losing fresh fruit aromas and acidity while gaining flab and alcohol. Maybe in this case the unsubtle nudge from Mother Nature is just what is needed to save the harvest, assuming everyone gets their grapes in on time. We shall see.