A fast-spreading wildfire in California's wine country sparked evacuation orders as firefighters battled the blaze Saturday.

A heat advisory for the area is in effect until 9 p.m. Saturday. Temperatures in Calistoga are expected to reach a low of around 59 degrees Friday night and a high of near 91 degrees on Saturday, with 5 to 7 mph winds. The chances of dry lightning are low but "not zero," the weather service said in its forecast discussion.

The fire was reported before noon at Highway 175 and McKinley Drive near Middletown. Thirty minutes later, authorities spotted a bloody man on Highway 29.

Sonoma, Napa and Solano counties will likely be impacted by smoke from the Pickett Fire, the Air District said Thursday.

In Napa County, the Pickett Fire has scorched over 1,000 acres in Calistoga, threatening several wineries and prompting evacuations