Heavy rainfall biggest concern as Hilda weakens

The National Weather Service discontinued a tropical storm watch for the Big Island on Wednesday evening as Hilda was forecast to weaken to a tropical depression overnight.

Forecasters continued to warn of heavy rains hitting the island, particularly on the east side. A flash flood watch went into effect at 6 p.m. Wednesday and will remain in effect until 6 a.m. Saturday.

Even while weakening, Hilda might produce between 6 and 12 inches of rainfall, with up to 18 inches possible at higher elevations.

“The big thing we’re concerned about is the rainfall potential,” said Kevin Kodama, weather service meteorologist, Wednesday afternoon.

Hilda’s center is forecast to pass about 100 miles to the south of the island, he said.

“There’s going to be uncertainty in the track and the effects of the system extend outward from the center,” Kodama cautioned.

A high surf warning was expected to remain in effect until this morning. Large and potentially life-threatening surf along east- and southeast-facing shores are possible during the next couple of days.

At 5 p.m. Wednesday, the storm was about 250 miles southeast of Hilo packing maximum sustained winds of 45 mph and moving northwest at 3 mph. Tropical storm force winds were extending outward up to 70 miles from the storm’s center earlier in the day.

Hilda’s forward movement was expected to increase through Friday.

Kodama said that’s good news since even a weak storm can be devastating if it is nearly stationary.

“If this system was as slow as it is right now as it moves south of the Big Island, that would be a tremendous problem,” he said.

Kodama said residents should remain cautious.

“We tell people all the time it doesn’t take a big system or a really strong system to cause a lot of flooding problems,” he said.

Email Tom Callis at tcallis@hawaiitribune-herald.com.