Hawaiian Electric Co. officials said it has crews on standby Sunday and plans to be fully staffed Monday when Tropical Storm Flossie is projected to hit the islands.

The National Weather Service late Sunday morning placed Oahu under a tropical storm warning, which means Flossie could bring winds of 39 mph or higher in the next 36 hours. Maui and Hawaii counties have been under the warning since 11 p.m. Saturday.

HECO spokesman Peter Rosegg said the company is watching the storm forecast closely and taking the usual precautions such as filling its trucks with gas and stocking them with maintenance supplies.

“We’re going through the standard procedures we go through when we know a storm like this is coming,” he said. “We’ll be ready to deal with whatever the weather brings us.”

Rosegg urged residents to make sure they have an ample supply of candles, battery-powered lamps, and batteries on hand in the event of an outage.