Felicia maintained its tropical storm strength Sunday evening, and forecasters predict it will reach the eastern Hawaiian islands by Monday night if it stays on its current track.

“Regardless of the strength of Felicia when it reaches the Hawaiian islands, heavy rains are still expected to occur and flash flooding remains a possibility,” the Central Pacific Hurricane Center said.

Felicia, once a powerful category 4 hurricane, now has 50 mph maximum sustained winds with higher gusts and is moving west at 10 mph. As of 11 p.m. Sunday, it was about 395 miles east-northeast of Hilo and about 560 miles east of Honolulu.

“On this track, the outer winds from Felicia are expected to reach the easternmost Hawaiian islands Monday night,” according to the Central Pacific Hurricane Center’s 11 p.m. advisory.

 The latest track shows Felicia traveling north of the Big Island and into Oahu Tuesday afternoon.

Tropical storm force winds of 39 mph or more extend outward up to 140 miles from the center, the weather service said.

A swell generated by Felicia has already reached the Big Island and Maui and will hit the rest of the islands by Monday.

A tropical storm watch has been issued for Oahu, the Big Island, Maui, Molokai, Lanai, and Kahoolawe. A tropical storm watch means tropical storm conditions are possible in the watch area within 48 hours.

Rainfall and the areas affected are dependent on the track Felicia takes, a weather service report said. “There is considerable uncertainty in the locations that will be affected,” it said.

A flash flood watch will be in effect for Kahoolawe, Lanai, Maui, Molokai, and the Big Island from Monday morning. A flash flood watch on Oahu will begin Tuesday morning.

“Felicia is expected to produce extremely heavy rainfall with the potential for widespread flash flooding, increasing on Tuesday and continuing into Wednesday,” the weather service said.

People in flood-prone areas need to prepare for the possibility of torrential rains and rock and mudslides. Flooding rainfall could occur well away from the center of Felicia.

A high surf warning is in effect for Maui and the Big Island until Tuesday night. The surf will likely exceed the warning level of 15 feet tomorrow.

Public schools will remain open tomorrow, the Department of Education Web site said. One charter school, West Hawaii Explorations Academy on the Big Island, will be closed tomorrow.

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