Tropical storm watch issued for Hawaii’s Big Island as Hone approaches

Tropical Storm Hone became the eighth named storm of the Pacific Ocean hurricane season late Thursday while cruising toward the islands of Hawaii.

Hone is on course to pass near but probably south of the Big Island late Saturday into early Sunday. It should be either a strong tropical storm or a low-end hurricane at its closest pass.

Whether the core of the storm – and its strongest winds and heaviest rain – affects the state is somewhat uncertain. Significant rain is probable regardless, and large waves will batter southern coasts.

A tropical storm and flood watch is in effect for the Big Island. Tropical storm warnings have been hoisted for offshore waters of all of the Hawaiian islands.

While rain and dangerous surf will probably be the biggest impacts, gusty winds could cause some isolated damage, and more storms may follow in Hone’s wake.

Where is the storm and how strong is it?

About 650 miles southeast of Hilo, Tropical Storm Hone has struggled to organize since it was named Thursday.

The storm had sustained winds of 45 mph early Friday local time, and a central pressure of 1,003 millibars. It is expected to slowly strengthen over the next few days.

How close to Hawaii will it pass?

Hone is forecast to pass about 75 to 100 miles south of the southern tip of the Big Island. This part of the southern coast is very sparsely populated and consists mainly of beaches, parks and reserves.

The National Hurricane Center forecasts Hone to be a strong tropical storm or on the cusp of hurricane intensity as it passes the Big Island, with sustained winds about 65 to 75 mph.

What are the expected impacts?

Typical trade wind showers with winds out of the east are expected Friday before precipitation rates increase Saturday with the approach of Hone, particularly on the Big Island.

By late Saturday and into Sunday, the Big Island and Maui should be seeing relatively steady and occasionally heavy rain. The rain should begin to wane into Monday.

Windward-facing and mountainous locations of Hawaii are likely to see the most rain.

Totals up to a foot or more are expected on east- and south-facing slopes of Mauna Kea and Mauna Loa on the Big Island. Elsewhere, amounts of at least 2 to 6 inches are probable. Similar totals are expected in Maui, but lower amounts are expected on leeward slopes (opposite the prevailing wind direction) and on islands to the northwest, including Kauai and Oahu.

“Given the potential for prolonged heavy rainfall, localized flash flooding could occur if the rain becomes concentrated,” wrote the Weather Service office in Honolulu.

Winds will be strongest in coastal areas, especially on the Big Island, as well as at high elevations and in channels between islands. Spots with the greatest potential for wind damage should be the south coast of the Big Island, Maui and Molokai.

“Winds will strengthen through the weekend across the state with widespread gusts to 40 mph possible Saturday, and up to 50 mph on Sunday,” the Weather Service wrote.

Most other spots should see gusts to at least 30 or 40 mph.

Waves around 9 to 12 feet are forecast on the most exposed east- and south-facing shores, with 5-to-10-foot breakers in most other spots. Wave heights near 20 feet are expected to pass just south of the Big Island, but a small shift northward could increase shoreline wave heights.

Could the storm spark fires?

Even if Hone passes south of the Big Island and does not generate much rain, gusty winds could increase the risk of wildfires.

This is particularly true in locations where winds blow downward out of the mountains, which may not see much rain, and in northern parts of the Big Island or southern Maui, which are experiencing extreme drought.

Winds are not expected to be anywhere near as strong as those that fanned the catastrophic fires in Maui in 2023, however.

What will follow Hone?

Hawaii could face additional storminess after Hone passes.

Well to the east of Hone, Hurricane Gilma – with peak winds of 120 mph – is spinning toward the central Pacific, about 1,900 miles east of Hilo, Hawaii.

Gilma is churning westward on a track that could bring it close to Hawaii in six or seven days. The storm is farther north than Hone, which should allow it to run into colder water, which will probably cause it to weaken.

The main threat from the storm – assuming it affects the islands and does not veer away – appears to be more rainfall, especially on the Big Island and Maui.

And that’s not all. On the heels of Gilma, a third storm is likely to develop. This one is probably 10 days from nearing Hawaii, but its track forecast remains uncertain.

How unusual are tropical storms in Hawaii?

On average, Hawaii is directly impacted by a tropical storm or hurricane about once every year or two. In reality, they tend to come in clumps during years with favorable weather patterns.

According to historical records from the National Oceanic and Atmospheric Administration, the most recent named storm to strike Hawaii was Linda in 2021. It passed north of the Big Island and hit Molokai as a weak tropical storm. The last tropical storm to make landfall on the Big Island was Darby in 2016.

Major hurricanes, rated Category 3 or higher, have threatened and hit the islands in a few instances, but cooler water in the region often weakens storms. In 2018, Walaka moved up from the south and reached uninhabited portions of the island chain as a Category 3. Iniki was the last major hurricane to directly strike population centers, when it hit Kauai as a Category 4 in 1992.