HONOLULU, HI — Hawaii officials warned residents and visitors to prepare for heavy rain, dangerous winds and flash flooding as Hurricane Lowell moved toward the western end of the state. The storm weakened to a Category 2 hurricane Monday afternoon, but forecasters still expected it to pass near Kauai and Niihau late Monday night into Tuesday morning.

The strongest effects were expected between 6 p.m. Monday and 6 a.m. Tuesday local time. As Lowell tracked a little farther east, officials said Kauai County faced the greatest risk, with the National Hurricane Center issuing a hurricane warning for Kauai County and a tropical storm warning for Oahu, including Honolulu.

Hurricane and tropical storm warnings cover different parts of the islands

The National Hurricane Center said hurricane conditions were likely in Kauai County by late Monday. That warning covers Kauai and Niihau, where the storm’s core could produce the most severe weather as it moves by the islands.

Farther east, a tropical storm warning was in effect for Oahu, including Honolulu, with tropical storm conditions expected later Monday into the evening. Hawaii emergency officials said the shift in the forecast path slightly increased the chance of significant impacts for Kauai County, even though Lowell’s strength had edged down compared with a day earlier.

Officials said the threat was not limited to wind. They also warned of dangerous surf along exposed southern and western shores on Kauai, Niihau and Oahu.

Schools and government offices on Kauai were set to close Tuesday

The Kauai Emergency Management Agency said public schools on Kauai, County of Kauai offices and State of Hawaii offices on Kauai would be closed on Tuesday, Sept. 8, because of the expected storm impacts. Governor Josh Green said the county was most vulnerable to Lowell and that officials would not take chances with public safety.

In the resort town of Poipu on Kauai’s southern coast, officials told residents to stay off the roads and urged tourists to shelter in place. Campgrounds and parks in the area were closed as part of the preparations.

Those steps reflected the timing of the storm, with the most hazardous conditions expected overnight and into the early hours of Tuesday.

Rainfall totals could trigger flash flooding and mudslides

Hawaii officials said Lowell could dump 6 to 10 inches of rain on Kauai, with a possible maximum total of 16 inches. On the Big Island, officials expected 4 to 8 inches, with isolated totals of up to 12 inches possible.

That amount of rain could lead to significant flash flooding and mudslides, especially in Kauai County and parts of the Big Island. Officials also warned that the combination of heavy rain and strong winds could create hazardous travel conditions and make cleanup difficult even after the worst weather passes.

The Hawaii Emergency Management Agency said wind gusts could reach 74 miles per hour in Kauai County and 40 miles per hour on Oahu on Monday and Tuesday.

Officials warned coastal residents to be ready to leave if needed

Emergency officials asked people living along the coast or in low-lying areas to be ready to evacuate if conditions worsen. The warning was part of a broader push to get residents to prepare before the storm’s peak impacts arrive overnight.

The Kauai Emergency Management Agency told residents to secure loose items around their homes, fill up gas tanks, charge phones and other devices, refill prescriptions and make sure they have enough water, food and emergency supplies. Officials also warned that power outages were possible because of high winds and flash flooding.

Those precautions were aimed at helping households ride out the storm if roads become dangerous or services are interrupted.

Dangerous surf and possible tornadoes add to the threat

In addition to rain and wind, Hawaii emergency officials said extremely dangerous surf could hit the southern and western exposed shores of Kauai, Niihau and Oahu. Swells of that kind can make coastal areas hazardous even before the center of a storm comes close.

Officials also said a few tornadoes were possible Monday afternoon through Monday night, especially on Kauai and Niihau. That risk added another layer of concern for residents and emergency managers already watching for flooding, wind damage and possible power failures.

As Lowell moved toward the islands, officials said the main message remained the same: prepare early, follow local instructions and be ready for fast-changing conditions through Tuesday morning.