Strong offshore winds and extremely dry conditions will result in widespread critical fire weather conditions throughout California on Thursday, according to the National Weather Service. Strong surface high pressure in the Great Basin will promote strong northeasterly Santa Ana winds.
Critical conditions, with sustained northeasterly winds of 20 mph and above and relative humidity of 10% to 20%, will occur across the Transverse Ranges of Southern California, including portions of eastern Ventura County to southern Riverside County, the National Weather Service said. Winds could gust to more than 30 mph locally with the lowest humidities from early to midmorning into early afternoon.
Widespread elevated to locally critical conditions will also occur in Northern California, especially in the northern Sacramento Valley and adjacent western slopes of the northern Sierra and western slopes of the northern Coast Ranges.
Southern California population centers listed at critical risk include Santa Ana, Anaheim, Riverside, San Bernardino and Oxnard. Population centers at extreme risk include Ontario, Fontana, Santa Clarita, Rancho Cucamonga and Pomona.
The Colorado River Valley will get northerly winds of 15 to 25 mph with low humidity.