Hawaii's Big Island under storm warning as Hone approaches with rain, wind

Tropical Storm Hone is expected to whip gusts and drop rain on the southern edges of Hawaii this weekend, potentially inflicting flooding and wind damage on the Big Island and raising the risk of wildfires on the drier sides of the islands.

The National Weather Service has issued a tropical storm warning for Hawaii County, which includes all of the Big Island and a red flag warning for the leeward sides of all islands.

Hone, which means sweet and soft in Hawaiian, will likely gradually strengthen and become a strong tropical storm as it passes south of the islands Saturday and Sunday, the National Weather Service said.

It's expected to become a Category 1 hurricane for a 12-hour period on Sunday but will likely be past the Big Island by that point, said Laura Farris, a weather service meteorologist in Honolulu.

The Hawaii Tourism Authority told travellers it's still safe to come to the islands but recommended that people postpone outdoor activities.

We are not advising visitors to cancel their trips, the agency said in a news release.

Hone was 425 miles (685 kilometres) east-southeast of Hilo and 640 miles (1,025 kilometres) east-southeast of Honolulu late Friday.

The eastern and southeastern parts of the Big Island could get 5 to 10 inches (11 to 25 centimetres) of rain. The island could get sustained winds of 20 to 40 mph (32 to 64 kph) and gusts near 60 mph (97 kph.)

The dry air north of the storm will spread arid conditions across the archipelago on Saturday, which combined with strong winds, will raise wildfire risks. Most of the state is already abnormally dry or in drought, according to the US Drought Monitor, amplifying the hazards.

The weather service's red flag warning will be in effect from 10 am to 6 pm on Saturday. It issues the alert when warm temperatures, very low humidity and stronger winds combine to raise fire dangers.

The situation recalls last year's deadly wildfires on Maui, which were fuelled by hurricane-force winds. But Farris said the wildfire risks from Hone are lower.

The August 8, 2023, blaze that torched the historic town of Lahaina caused the deadliest US wildfire in more than a century. Powerful winds whipped up in part by a hurricane passing to Hawaii's south helped fuel the flames that killed 102 people. Dry, overgrown grasses and drought helped spread the fire.

The state's two power companies, Hawaiian Electric and the Kauai Island Utility Cooperative, both said they would be monitoring conditions this weekend in case they needed to shut off power to reduce the chance live, damaged powerlines could start fires.

The cause of Lahaina blaze is still under investigation but it's possible it was ignited by bare electrical wire and leaning power poles toppled by the strong winds.

To Hone's east, Hurricane Gilma was moving across the Pacific as a Category 2 storm and was expected to weaken as it heads over cooler waters and encounters drier air in coming days. It's forecast to become a tropical depression by Wednesday.

Gilma may bring rain to Hawaii but it's not clear how much, Farris said.