CNN  — 

Hawaii Gov. David Ige urged residents Wednesday to prepare weeks’ worth of supplies ahead of Hurricane Lane, a Category 4 cyclone that could make landfall in the islands in the coming days.

He said government offices would be closed Thursday and Friday as the storm, packing heavy rains, approaches the state.

“Just want to remind everyone to prepare to shelter in place 14 days of food and supplies and water,” he said at a news conference.

The storm’s dangerous center could make landfall as it moves past the islands from Thursday through Saturday. But even if the eye doesn’t cross land, it should draw close enough to the islands that it brings destructive winds and rain accumulations over 20 inches in some locations, forecasters said.

Forecasters said the storm was moving to the west-northwest but was expected to make a harder turn toward the northwest and north-northwest over the next 24 hours.

Track the storm here

How soon it turns and how sharp it turns will determine how close the center gets to the islands and how much damage it will cause.

“Exactly when this critical turn will happen is very difficult to forecast, so confidence in this portion of the track is unfortunately rather low,” The Pacific Hurricane Center said.

At 8 p.m. ET the storm was located about 275 miles south of Kailua-Kona, or 400 miles SSE of Honolulu.

People have been flocking to stores for supplies.

“(I’m) filling up my bathtub with some water, hoping to board up my main windows in time,” a shopper on the Big Island, Shana Bartolome, told CNN affiliate KHON on Tuesday.

Shoppers were going for generators, toilet paper, water and other supplies, KHON reported.

“It’s going to be close, but hope for the best and with luck make sure everybody’s ready, and if it doesn’t hit us, that’s good,” Oahu resident Vesega Pili told the station.

Ige said officials were expecting some roads to flood and residents should refrain from driving.

“We just need to urge people to use common sense,” he said.

The storm was in the Pacific about 285 miles south of the Big Island town of Kailua-Kona early Wednesday, with maximum sustained winds of 155 mph. Tropical-storm-force winds persist up to 140 miles from the center.

Lane is expected to weaken slowly through Friday, but it still is forecast “to remain a dangerous hurricane as it draws closer to the Hawaiian Islands,” the National Weather Service’s Central Pacific Hurricane Center says.

A hurricane warning is in effect for Hawaii and Maui counties – meaning hurricane conditions are expected there.

A hurricane watch has been issued for Oahu and Kauai. The watch indicates hurricane conditions are possible and that winds of at least 39 mph are anticipated in the next two days.

Hurricane Lane watches and warnings 8/22/18 noon ET

American Airlines and Hawaiian Airlines issued travel advisories to customers flying to or from Hawaii. Both are waiving reservation change fees as the hurricane approaches.

What to expect

Tropical-storm-force winds – 39-73 mph – and rain could arrive at the Big Island and Maui County late Wednesday and early Thursday, and at the other islands Thursday or Friday.

Hurricane winds (74 mph and higher) could hit the Big Island and Maui County on Thursday.

Hurricane Lane is shown in a satellite image from Wednesday morning.

In addition to strong winds, the primary threats will be rough surf, coastal erosion and heavy rainfall, even if the center of the storm does not move directly over the islands.

Through Saturday, 10-15 inches of rain are generally expected, with isolated amounts greater than 20 inches, the Central Pacific Hurricane Center said.

The downpours could lead to landslides and flooding.

Hurricane Lane is a rare threat for Hawaii

Hurricanes rarely make landfall in Hawaii, as the Central Pacific does not see as many storms as the Atlantic or Eastern Pacific, and the Hawaiian Islands present a small target in the vast Pacific Ocean.

Only two hurricanes and two tropical storms have made landfall in Hawaii since 1959:

• Hurricane Dot, in 1959

• Hurricane Iniki, in 1992

Tropical Storm Iselle, in 2014

Tropical Storm Darby, in 2016

Even close calls are somewhat rare, with Hawaii getting a named storm within 60 miles of its coastline about once every four years on average.

Lane represented another kind of rarity: It was a Category 5 storm late Tuesday before weakening Wednesday morning.

As such, this was only the second time in recorded history that a Category 5 hurricane came within 350 miles of the state – the first one being Hurricane John in 1994 – the National Weather Service said.

As you may have heard, Hawaii has been experiencing a volcanic eruption for much of the summer. Mount Kilauea began producing lava flows in early May and portions of the southeastern coastline of the Big Island have been transformed by the lava flows which covered over 13 square miles (35 square kilometers).

Fortunately the eruptive activity of Kilauea has “paused,” with no new lava flows since August 9, according to the Hawaiian Volcano Observatory.

Since there is not much lava reaching the ocean anymore, the hurricane shouldn’t have too much of an impact on the volcano region, according to Denison University Geophysicist Erik Klemetti.

CNN’s Steve Almasy, Keith Allen and Joe Sutton contributed to this report.