Bay Area residents are bracing for a weekend of heightened wildfire risk as strong, dry winds sweep the region. The National Weather Service's San Francisco office has issued a Red Flag Warning starting Thursday night and extending until Saturday evening. This alert, which includes the Santa Cruz area, signals critical fire weather conditions due to offshore winds reaching 25-35 mph, with gusts up to 45 mph and isolated gusts that could hit a staggering 65 mph across higher terrain and ridgetops. The combination of such strong winds and daytime humidity levels plunging as low as 10% makes the situation particularly dire.
According to the National Weather Service San Francisco, an "inside slider", a meteorological scenario indicative of a major high-pressure system, is ushering in Red Flag conditions across the region. Areas like the North Bay Interior Mountains, Interior East Bay, and Eastern Santa Clara Hills can expect northerly winds of 20-30 mph, with gusts up to 50 mph. These winds ramp up fire danger and complicate air travel with non-standard wind directions and potential low-level wind shear, especially between 03Z-06Z.
During this period, residents are urged to practice extreme caution to prevent wildfires, as the "offshore gradient will promote northeasterly/offshore winds that will result in rapid drying and compressional warming," according to the forecast discussion by NWS San Francisco. The most challenging times for fire risk are predicted to be from Thursday night into Friday morning and from Friday night into Saturday morning, where winds may gust as high as 65 mph through certain passes and ridgetops. Despite near-average fuel moisture for this time of year, the arid conditions expected from the event could drastically escalate fire potential.
Marine conditions are also expected to be rough, with gale warnings in effect and northwest winds anticipated to build from a fresh breeze to near gale force by late Thursday morning, causing wind waves to reach 12-14 feet by that evening. The turbulent seas are forecast to persist until Saturday, after which the offshore pressure gradient is slated to weaken, reinstating more stable onshore flow to the Bay Area.
