(PD) - The threat of rain in mid-October would typically have winemakers and vineyard managers scrambling as they look to limit any damage caused by severe rot or other moisture-related harm to the North Coast’s most valuable crop.

But the rainfall expected to come into the area beginning Tuesday is more of a minor inconvenience due to the fact that most grape growers are done or about to finish this season’s harvest.

Thanks to early picking that started at the end of July, about 90 percent of the harvest is complete in Sonoma County, a point that in most years wouldn’t come for two more weeks.

“The short version is our Sonoma properties are pretty much done,” said Andrea Smalling, chief marketing officer for Foley Family Wines. The company still has some late-harvest semillon to be picked at vineyards in the Chalk Hill region, but even the coming rain is a blessing for that fruit, as it spurs what growers call “noble rot” that allows the grapes to shed water to make a more flavorful sweet wine.

“That is OK because if it rains, then you get a few dry days, it actually encourages the additional growth of botrytis and a little rot. So, that is actually a good thing,” Smalling said.

About 95 percent of the crop has been picked in Napa County.

A cold front bringing a few showers will come into the region Tuesday night and linger through Wednesday morning, dumping about 0.10 of an inch of rain, said Ken Clark, a senior meteorologist with AccuWeather.

A second storm front is expected Friday, though it is bringing fairly light rainfall, Clark said. Temperatures will struggle to break past 70 degrees for the rest of the week. In essence, fall weather has finally arrived.