Jimena weakened into a tropical storm on Saturday but the powerful swells generated by its approach will continue to produce hazardous surf along eastern shores of the main Hawaiian Islands through Sunday, according to the National Weather Service.
A flood advisory was posted for Maui at 12:19 p.m. Sunday after radar showerd a nearly-stationary area of heavy rain from Ulupalakua to Hamoa. Forecasters said rainfall rates of 1 to 2 inches per hour are possible.
The advisory is in effect until 3:15 p.m. Locations in the advisory include, but are not limited to, Ulupalakua, Wailea, Nahiku, Keanae and Hana.
At 11 a.m. Sunday, Jimena was about 650 miles east-northeast of Honolulu and 725 miles east-northeast of Lihue, moving northwest at 9 mph.
Jimena was sporting maximum sustained winds of 50 mph, with tropical storm-force winds extending outward up to 205 miles.
The storm is expected to steadily weaken as it continues toward the northwest with a slight decrease in forward speed over the next few days. Forecasters predict it will turn toward the west-northwest by Monday.
A high surf advisory is in effect for the south shores of all islands, and a high surf warning is in effect for the eastern shores of Kauai, Oahu, Molokai, Maui and the Big Island, both posted through Monday at 6 p.m.
Forecasters predict surf of 10 to 18 feet along eastern shores, and 5 to 8 feet on south shores.
The public is advised to expect ocean water sweeping across beaches, coastal benches and lava flows, impacting coastal properties and roadways. In addition, most beaches will be vulnerable to powerful currents; large breaking waves and strong currents could impact harbor entrances and channels.
Beachgoers are further advised that large breaking surf, significant shorebreak and dangerous currents could make entering the water very hazardous. Inexperienced ocean users are warned to stay off beaches and adjacent beachfront areas, the weather service said.
On Saturday, high surf conditions prompted the cancellation of the annual Waikiki Roughwater Swim. The event, usually scheduled for Labor Day, had been moved up due to the expected arrival of jellyfish. The race will not be rescheduled.
While heavy rains that drenched much of the state on Friday subsided on Saturday, Oahu and Kauai county remain under a flash flood watch until 6 p.m. Sunday due to the continued threat of heavy showers and thunderstorms generated by a band of moisture extending south from the remnant of Hurricane Ignacio and a trough northwest of the islands.
Saturated soil from the recent heavy rains also increase the risk for flash flooding.
The moist and unstable airmass to the west of the state could keep things wet on Oahu and Kauai through Sunday afternoon. However, forecasters predict drier weather early in the coming week as a slightly drier airmass moves in from the east on Monday and Tuesday.
All forecasts beyond mid-week are conditional based on the track and intensity of Jimena.
"The current forecast has us remaining in a rather light wind regime with a wetter weather pattern expected due to increased moisture from Jimena," the weather service reported. "However, if Jimena tracks closer to the islands we could see more significant impacts."
The weather service is advising the public to keep close track of weather updates over the coming week.