A hurricane warning for the Big Island is now in force as Tropical Storm Lala pushes steadily toward Hawai’i, and forecasters expect the system to reach hurricane strength before it arrives. The warning stays in effect until further notice, replacing the hurricane watch that had been posted earlier.

Where the Storm Stands

As of 5 p.m. Thursday, Lala sat roughly 550 miles east-southeast of Hilo — about 770 miles east-southeast of Honolulu. Maximum sustained winds measured 60 mph, with the system tracking west-northwest at 12 mph.

Forecasters at the Central Pacific Hurricane Center anticipate the storm will accelerate along that west-northwest heading over the coming days. Current projections place Lala near the Big Island by Saturday, with the system then passing to the south of the remaining islands later in the weekend.

Tropical storm force winds already extend as far as 275 miles from the centre.

The National Weather Service in Honolulu has also issued a tropical storm watch covering Maui County.

What to Expect: Wind

Hurricane conditions are forecast to reach the Big Island by early Saturday. Maui County could see tropical storm conditions developing late in the day.

One detail deserves particular attention. Winds along ridgetops and windward slopes commonly run about 30 percent stronger than the near-surface figures quoted in advisories, and certain elevated spots can exceed even that margin. Some locations on the Big Island face the prospect of gusts reaching 110 mph.

Anyone living at elevation should treat the headline wind numbers as a floor, not a ceiling.

What to Expect: Rainfall

The rainfall picture is arguably the more serious threat.

General totals of 8 to 12 inches are forecast across Maui County and the Big Island, with the Big Island potentially seeing maximum accumulations up to 25 inches. The rest of the chain should expect 4 to 6 inches, with isolated totals reaching 8 inches.

Upslope and windward areas will bear the worst of it. Those zones on the Big Island could take 10 to 15 inches, with Maui’s equivalent areas seeing 8 to 12. Localised amounts may climb higher still — up to 25 inches on the Big Island and 15 on Maui.

Heavy rain is expected to begin Friday evening and continue through Saturday night.

Rainfall of that magnitude on steep terrain carries an obvious consequence: life-threatening flooding and mudslides.

Flood Watch in Effect

A flood watch now covers portions of the Big Island and Maui County through late Saturday night, with flash flooding possible from the excessive rainfall.

Practical impacts to anticipate include:

• Closures on flood-prone roads and low-lying stretches
• Streams overflowing their banks as runoff climbs
• Significant flooding and property damage in urban areas where water sheds quickly

Residents should watch for updated forecasts from the Honolulu office and be ready to act immediately if flash flood warnings are issued. Location-specific information, including inland watches and warnings, is available online.

Storm Surge and Surf

Surge combined with tide will push water into normally dry coastal areas. Where peak surge coincides with high tide, inundation of 1 to 3 feet above ground level is possible. The deepest water will sit along the immediate shoreline, accompanied by large and dangerous waves.

Swells generated by Lala should reach east-facing shores on Friday, then spread westward and build through the weekend. Expect life-threatening surf and rip currents.

There is also some tornado potential associated with the system, with limited impacts anticipated around the Big Island.

Marine and Coastal Advisories

A tropical storm warning covers offshore waters of the Hawaiian Islands out to 240 nautical miles, including the section of the Papahānaumokuākea Marine National Monument lying east of French Frigate Shoals.

Separately, a high surf advisory runs through 6 a.m. Friday for south-facing shores. A long-period south swell was expected to peak Thursday at advisory levels, producing breaking waves of 8 to 12 feet before easing overnight, though conditions may linger near advisory thresholds into Friday.

Ports Ramping Up

The Coast Guard captain of the port in Honolulu is escalating heavy weather conditions at commercial ports in Maui and Hawai’i counties.

• Hawai’i County: moving from X-ray to Yankee at 8 p.m. Thursday, then to Zulu at 8 a.m. Friday
• Maui County: moving from X-ray to Yankee at 8 a.m. Friday
• City and County of Honolulu: holding at X-ray
• Kaua’i County: holding at Whiskey

For those unfamiliar with the terminology: Whiskey is set when sustained gale force winds of 39 to 54 mph are expected within 72 hours, and X-ray when they are expected within 48. Yankee means sustained tropical storm force winds of 39 mph are anticipated within 24 hours — incoming traffic requires specific approval, cargo work must stop within 12 hours, and lightering and bunkering cease. Under Zulu, all cargo operations halt and the port closes.

Water Supply Warning

The Hawai’i County Department of Water Supply is urging customers to prepare for drinking water needs ahead of the storm.

The reasoning is straightforward: high winds knock out electrical power, and power failures interrupt water service. Anyone dependent on a continuous county water supply should assess their situation now. Guidance on safe water storage appears in the department’s emergency preparedness guide, available online.

Shipping Disruptions

Young Brothers is coordinating with the Coast Guard and state agencies and made several schedule adjustments Thursday.

Honolulu to Nāwiliwili, Kaua’i and Kahului, Maui: sailing unchanged, with Honolulu accepting refrigerated and hazardous straight-load cargo.

Honolulu to Kawaihae, Big Island: cancelled. The Kawaihae port closes to inbound traffic at 8 p.m. Thursday and to outbound traffic at 8 a.m. Friday while crews secure cargo. A pickup window runs 7:30 to 11:30 a.m. Friday for dry straight-load and palletised cargo only — no refrigerated goods, hazardous materials or livestock. The next sailing departs 17 August, arriving the following day.

Bottom Line

Lala is not yet a hurricane, but forecasters expect it to become one before it reaches Hawai’i County. The window for preparation is Friday. By Saturday morning, the decisions residents make today will already be locked in.