Adhering to early forecasts, a weaker, slower Hurricane Hilda continued to move west-northwest toward Hawaii on Sunday.

The storm, which hit peak intensity Saturday as a Category 4 hurricane with 135 mph winds, was downgraded to a Category 2 hurricane Sunday.

As of 5 p.m. Hilda was 545 miles east-southeast of Hilo and 760 miles east-southeast of Honolulu, moving west- northwest at 8 mph, according to the Central Pacific Hurricane Center on Oahu. Maximum sustained winds were 100 mph.

A relatively compact hurricane, Hilda’s hurricane-force winds of 74 mph or more extend just 25 miles from the center, and its tropical storm-force winds of 39 mph or more extend 70 miles out.

“It’s still far enough away that there’s a lot of uncertainty (in Hilda’s path),” said Derek Wroe, a forecaster with the National Weather Service in Honolulu.

The storm is expected to weaken significantly Monday and Tuesday, according to the center.

As they did with the former Hurricane Guillermo, which had a close encounter with the islands last week, Air Force Reserve hurricane hunter airplanes were scheduled to begin flying missions into Hilda on Sunday evening, hurricane center forecasters said.

Hilda’s immediate effect on the islands will be high surf along the east and southeast shores of the main Hawaiian Islands.

A high-surf advisory for east-facing shores of the Big Island and Maui is in effect through 6 a.m. Wednesday, according to the weather service.

The recent hurricane activity in Hawaii waters coincides with the publication of a new study that suggests that areas near fringing reefs may be more likely to experience tsunamilike conditions during major storms. Fringing reefs are common in Hawaii.

By examining the impact of Typhoon Haiyan on the reef-protected town of Hernani in the Philippines, Tohoku University researchers Volker Roeber and Jeremy Bricker (a former University of Hawaii postgraduate researcher) found that the short wave-breaking zone found with fringing reefs can contribute to the formation of large, tsunamilike waves capable of inflicting severe damage and high casualties.

The findings were published in the Aug. 6 edition of the journal Nature Communications.