The National Weather Service has issued a Red Flag Warning for the Sierra Nevada through 5 AM Monday morning.
This is for zone 221 which is the Stanislaus National Forest and zone 296 which includes Yosemite National Park.
Lightning storms are possible during this time period. Rainfall will be very light, generally less than a tenth of an inch. Lightning with gusty winds will be the main threat.
Winds in the Sierra Nevada are expected to range from ten to twenty mph, with gusts up to forty-five mph in the highest locations. Winds near thunderstorms will be erratic and gusty.
The system may spread over the Mother Lode and the central valley and end on Monday morning. As the system draws to an end, these may be wet thunderstorms with substantial lightning, brief heavy rain and small hail.
The threat of more thunderstorms will remain through Monday night.
Hikers, campers and boaters should monitor the weather and seek shelter at once if threatening weather approaches. Lightning can strike several miles from the storm location. Report any lightning-started fire to your local fire department.
A Red Flag Warning means that critical Fire Weather conditions are either occurring now or will shortly. A combinaton of lightning, low relative humidity, very dry fuels and locally gusty winds can contribute to extreme fire behavior.