Forecasters said triple-digit temperatures, deep atmospheric mixing, locally gusty winds and low humidity in interior areas could produce elevated to briefly critical fire weather conditions.
The tropical moisture is expected to move out of the region Friday night, clearing the way for a cooler and drier weekend.
Monday is expected to remain relatively quiet with below-normal temperatures and coastal low clouds.
Forecasters are already monitoring another potential influx of tropical moisture next week. A disturbance developing off the Baja California coast is expected to become a tropical storm, and about half of forecast projections show some of its moisture reaching Southern California between Tuesday and Thursday.
Only about 10% of the projections currently produce rain, however.