A Red Flag Warning for the higher elevations of Napa County and extreme eastern Sonoma County has been extended until 3 p.m. Sunday,  according to the National Weather Service.

Gusty north winds and very dry conditions will persist in the higher hills tonight into Sunday creating high fire danger conditions. 

Authorities warn that any fires that develop will likely spread rapidly.

The NWS forecasts northerly winds of 10 to 20 mph with local gusts to 30 mph.

The strongest winds are expected in northern and eastern Napa county on Saturday night.

Winds will decrease Sunday morning and then switch to a westerly direction by late Sunday afternoon.