According to Cal Fire, the blaze had reached 4,690 acres as of Saturday, and was 7% contained, with crews working overnight to keep the fire within control lines.

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.

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