Heavy rain and thunderstorms could produce flood conditions across the state today and Monday as the remnants of former Tropical Storm Howard continue to move westward over the state.
A flash flood warning is in effect for all islands through Monday afternoon.
Forecasters predict abundant moisture from Howard and instability caused by an upper-level trough moving southward over the state will combine to create ideal conditions for locally heavy showers. That in turn could result in flash floods as rainfall hits ground still saturated from heavy rain associated with former Tropical Storm Darby, which passed over the state two weeks ago.
According to the National Weather Service, the northern end of the state is most likely to experience flash flooding.
Surf is also on the rise because of an east swell generated when Howard was still a tropical storm.
Wave heights of 6 to 9 feet are expected on east shores. A high-surf advisory is in effect through 6 a.m. today, but could be extended.
As the center of Howard moves near or over Oahu today, winds will shift and become light and southerly.
Derek Wroe, a meteorologist with the Honolulu office of the National Weather Service, said the heavy showers today into Monday could be spotty, with some areas getting heavy rain, while other parts of the island may see only a few showers.
Kauai and Oahu caught the brunt of Howard’s initial crossing over the state. Rainfall highs were recorded at Mount Waialeale (3.65 inches) and Kilohana (1.95) on Kauai and Lyon Arboretum (2.02) and Moanalua (1.63) on Oahu over the 24-hour period ending 7:45 p.m. Saturday.
The city’s Department of Environmental Services responded Friday night to a nearly 13,000-gallon sanitary sewer overflow at 2256 Seaview Ave. in Manoa.
Clogged debris caused the spill, which entered a storm drain at the intersection of Metcalf and Hunnewell streets, which eventually empties into the Ala Wai Canal. City crews arrived at the site at 10:30 p.m., and released the blockage at 10:55 p.m.
The city notified the state Department of Health and cleaned, disinfected and deodorized the affected area. The Health Department posted warning signs from the Kapahulu Library to the Ala Wai Boat Harbor and advised the public to stay out of the water until the signs are removed.
The discharge resulted in the cancellation of the second day of the Ala Moana Bowls bodyboard competition. The event will not be rescheduled.
Forecasters are also watching Tropical Storm Ivette, approaching the islands from the east. Ivette is expected to weaken into a remnant low as it nears Hawaii and turns northwest over cooler waters and wind shear tears it apart.
It still remains on track, however, to bring humid conditions and rain to the state as early as Wednesday. At 5 p.m. Saturday, Ivette had sustained winds of 45 mph and was moving west-northwest at 12 mph, about 1,245 miles east of Hilo.
