Felicia, once a powerful Category 4 hurricane, is now a “rapidly weakening” tropical storm with maximum sustained winds of 50 mph, forecasters said late this morning.

Still, they warn Hawaii residents to get ready for heavy rain, high surf and strong winds.

A tropical storm watch is in effect for the Big Island and Maui County. And residents of Oahu, Kauai and Niihau are advised to closely monitor Felicia’s progress, according to the Central Pacific Hurricane Center.

Forecasters say the east-facing shores will see high surf starting today.

At 3:30 p.m.. today, Felicia was centered about 480 miles east north east of Hilo, according to Big Island Civil Defense. The storm is moving west at about 14 mph with maximum sustained winds of about 50 mph and higher gusts. That’s down from 70 mph maximum sustained winds at 5 a.m. today.

On its current track, Felicia is expected to be approaching the islands late Monday as a “low end” tropical storm or a tropical depression, according to the hurricane center. The latest forecast has it moving past Oahu as a tropical depression on Tuesday.

 “Though weakening, Felicia will still be capable of producing torrential flooding rains, very high surf, and damaging winds,” forecasters warned.

The Big Island, Maui, Molokai, Lanai and Kahoolawe are also under a flash flood watch and a high surf warning until Tuesday afternoon, according to the hurricane center.

People in the watch areas should prepare now, listen for possible warnings and be ready to evacuate if necessary, officials said.

A tropical storm watch means that tropical storm conditions are possible in the next 48 hours. Tropical storms have maximum sustained winds of 39 mph to 73 mph.

At 11 a.m., tropical storm-force winds extended up to 105 miles from the center of Felicia.

The weather service said there is “considerable uncertainty” about where heavy rains and flooding could happen and about how long the rains will last. “All of these (factors) are dependent on the track Felicia ultimately takes,” the weather service said earlier.

Felicia peaked as a Category 4 hurricane with winds topping 140 mph on Thursday when it was still in the Eastern Pacific.