SAN DIEGO – California’s San Diego County remained under a red-flag warning for extreme fire danger Tuesday, as gusty Santa Ana winds and low humidity combined to heighten the risk of wildfires in the mountains and western valleys, and some local utility customers had their electricity shut off as a precaution.

The warning were to remain in effect until 10 p.m. Tuesday in the mountains and the western valleys. A high-wind warning was also in effect through noon in those areas.

Winds out of the east were expected to be between 30-40 mph, with gusts potentially reaching 60 mph in the mountains, according to the National Weather Service. The strongest winds were expected Tuesday morning, weakening slightly into the afternoon.

Humidity levels will drop to around 10 percent, with poor recovery expected overnight.

The red-flag warning means that outdoor burning should be avoided because any fires that develop will spread rapidly, according to the NWS. The high-wind warning advises that the gusty conditions may knock down trees or power lines, and travel will be difficult for high profile vehicles in wind-prone areas.

San Diego Gas & Electric warned Sunday that 50,483 customers in eastern San Diego County could face precautionary power shutoffs from Monday night through Wednesday, depending on the severity of the wind and potential for damage to power lines.

As of early Tuesday morning, 15,345 customers were without electricity in eastern San Diego County, with another 35,138 facing potential power shutoffs.

High temperatures Tuesday are forecast to reach 78 degrees near the coast, 80 inland, 83 in the western valleys, 76 near the foothills, 67 in the mountains and 78 in the deserts.

Conditions are expected to warm up Wednesday, then temperatures will drop slightly on Thursday and Friday, forecasters said.