Hurricane Madeline is expected to pass near Hawaii midweek, US weather forecasters said Monday, threatening dangerous flooding and disruptions to a planned visit by President Barack Obama and other dignitaries.

Currently a Category Three hurricane, Madeline is expected to pass "dangerously close" to Hawaii's Big Island on Wednesday, carrying heavy rain and strong winds, the US National Weather Service said.

The hurricane was some 575 miles (925 kilometers) east of Hilo, Hawaii at 0300 GMT Tuesday.

The storm has maximum sustained winds of 125 miles per hour, and was moving toward west-northwest at around 10 miles per hour.

Madeline was expected to begin turning gradually to the west, then move west-southwest Tuesday night into Wednesday.

It is expected to dump five to 10 inches (12.7 to 25.4 centimeters) of rain on Hawaii, with some areas receiving up to 15 inches.

"This rainfall may lead to dangerous flash floods and mudslides," the NWS Central Pacific Hurricane Center said.

Madeline's current path in the central Pacific could also coincide with Obama's planned visit to Hawaii to kick off the World Conservation Congress, a major meeting of thousands of delegates, including heads of state, scientists and policy makers.

The International Union for the Conservation of Nature stages the World Conservation Congress every four years at a different location around the globe.

It is set to take place from Thursday to next Saturday.

Obama is scheduled to address the gathering on its opening day.

He is also expected to travel to Midway Atoll, inside a newly named protected area, where the president burnished his environmental bona fides last week by establishing the world's largest marine reserve, home to thousands of rare sea creatures in the northwestern Hawaiian islands.

Meanwhile, another hurricane in the Atlantic, Gaston, was downgraded to a Category Two storm, US weather trackers said.

A Category Three hurricane earlier on Monday, Gaston was the first major hurricane of the Atlantic season.

The storm was packing top sustained winds of 105 miles per hour as of 0300 GMT Tuesday, around 600 miles east of Bermuda, the Miami-based National Hurricane Center said.

It was moving to the northeast at six miles per hour.

The storm was not an immediate threat to land, and was expected to remain near its current strength, picking up speed as it travels toward the northeast over the next couple of days, forecasters said.