The gloomy sky is threatening rain, but Lodi-area winegrape growers are optimistic that this week's storm won't destroy the unpicked vines.
There's no doubt heavy rains are coming soon, said Brian Edwards, a meteorologist for AccuWeather, a private forecasting firm.
"Between Tuesday night and Wednesday morning, the area could receive up to an inch of rain," he said. "A lot will fall in a 12- to 16-hour window."
Despite the forecast, growers feel confident the storm won't be devastating.
"Our growers have been picking feverishly to get as much off the vines as possible before the storm," said Stuart Spencer, program manager for the Lodi Winegrape Commission. "The rains will drop the sugar content in the grapes, but they will bounce back."
The biggest concern is not the rain itself, but the days following the storm, he said. Growers are hoping for sunny days with stiff breezes to help dry out the clusters and prevent bunch-rot, a condition in which mildew grows in between the individual grapes.
The showers should taper off by Wednesday afternoon and steady winds are expected to follow, but the sunny weather won't return until Friday at the earliest, Edwards said.
The rain could be the most damaging to grapes with thin skins and tight clusters, like zinfandel and petite syrah, said Ed VanDiemen, president of Lodi Grape Growers Association.
"We aren't so worried about the cabernets and merlots," he said. "They are a tougher grape."
Earlier in the growing season, farmers will dust their vines with sulfur spray to prevent mildew from growing on the budding grapes. But now it's too late in the season for sulfur and growers are at the mercy of Mother Nature, Spencer said.
Although cherry farmers will often have helicopters fly over orchards to blow-dry the crop, such an option isn't regularly employed by grape growers, he said.
"How farmers weather this storm is largely based on what they've done prior to it," Spencer said.
Based on remarks made by growers, Spencer said he believes this year's harvest will be equal to or smaller than last year's crush of 525,000 tons. The harvest still has about a month left, he said.
"Hopefully things cooperate," he said.
Contact reporter Jordan Guinn at email@example.com.