Lane's maximum sustained winds were about 155 mph, the National Weather Service said, which will slowly weaken over the next 48 hours.
The forecast puts the storm very close to the islands, with a direct landfall possible later this week.
The National Weather Service says that Hurricane Lane headed toward Hawaii has been is now a Category 4 hurricane and that some weakening of the storm is forecast over the next two days.
Lane is expected to take a northwest turn toward Hawaii Tuesday or Wednesday.
The storm had intensified slightly since the last report, with maximum sustained winds of 125 miles per hour with stronger gusts, traveling west at 14 miles per hour.
Landfalling hurricanes are very rare in Hawaii, as the Central Pacific does not normally see as many storms as the Atlantic or Eastern Pacific, and the Hawaiian Islands present a very small target in the vast Pacific Ocean.
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.
"Lane is forecast to move dangerously close to the main Hawaiian Islands as a hurricane Thursday through Saturday, potentially bringing damaging winds and life-threatening flash flooding from heavy rainfall", the Central Pacific Hurricane Center said, in its latest update.
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The U.S. Navy is moving its ships and submarines out of Hawaii as Hurricane Lane bears down on the state. Torrential rains associated with Lane is expected to affect portions of the state late Wednesday into the weekend.
In this scenario, 10 to 15 inches of rain would be possible over the island chain, with 20 inches or more not out of the question in the mountains.
Large swells generated by Lane will impact the Hawaiian Islands this week and they will produce "large and unsafe surf" and strong currents.
The storm may bring torrential rain, with the potential for "major flash flooding, landslides and mudslides".
State offices on Hawaii island and Maui will be closed Wednesday through Friday.
Meanwhile the weather service issued a high-surf advisory at 6 a.m. today to expire at 6 p.m. Tuesday, with 5- to 8-foot surf forecast for east-facing shores of the Big Island and Maui. "Even if the center of Lane were to remain offshore, it is important to remember that impacts from a hurricane can extend well away from the center".
It's one of only two recorded Category 5 hurricanes to pass within 350 miles of the Big Island's South Point.
The Latest on Hurricane Lane.