Expect rain as tropical storms Gilma and Hector approach and weaken from the east

Tropical storms Gilma and Hector are forecast to weaken considerably and bring rain as they approach the Hawaiian Islands, according to the National Weather Service.

As of a Wednesday morning forecast, Gilma was expected to pass slightly north of Maui County early Friday afternoon. As of 5 a.m. today, Gilma was located 715 miles east-southeast of Kahului.

Meanwhile, Hector was on a track to remain south of the islands, becoming a tropical depression Thursday afternoon. That storm was 1,540 miles east of Kahului.

Weather forecasters predicted that a high pressure ridge far north of the Hawaiian Islands and a broad plume of increased moisture will make conditions ripe for a wetter moderate to locally breezy trade wind pattern to persist through Thursday. The moisture will be carried on trade winds and bring scattered to numerous showers mainly to windward and mauka areas, especially overnight and in the early-morning hours.

If Gilma drifts farther north, there will be less rainfall for the islands, but a shift to the south will bring more rain, forecasters said. Widespread flooding is not expected, but localized flooding could be possible.

Remnants of Tropical Storm Hector will follow closely behind Gilma as a weak surface weather system and some rain Saturday night and into Sunday. It’s expected to bring a slick increase in rain showers, but no significant impacts from Hector based on the most updated forecasts.

Tropical Storm Hone has passed well west of the islands. When it was a hurricane, it dumped heavy rainfall on the islands, especially the Big Island which saw several rain gages along its windward and southeast slopes reporting two-day rain totals of more than 20 inches for Saturday and Sunday. Forecasters said that, fortunately, rain rates were mostly below an inch an hour, which mitigated more serious flooding beyond road closures in low-lying areas.

For Maui County, the highest two-day rainfall total associated with Hone was 10.78 inches at Puʻu Kukui in the West Maui Mountains, followed by 8 inches at West Wailuaiki in East Maui and 3.63 inches at Puʻu Aliʻi on Molokaʻi.

A tropical storm warning remains in effect for all Hawaiian waters, with seas churning at 6 to 7 feet today and peaking at 6 to 11 feet tonight and Thursday. Winds are blowing out of the east from 12 to 23 mph, and they are expected to intensify to 23 to 40 mph tonight and Thursday. Isolated thunderstorms are forecast for southeast waters.