Hurricane Guillermo has entered the Central Pacific with sustained maximum winds of 105 mph and is expected to weaken into a tropical storm that threatens the Hawaiian islands by the middle of the week.

At 11 p.m. Saturday, Guillermo was about 925 miles east-southeast of Hilo, and 1,135 miles east-southeast of Honolulu, moving west-northwest 14 mph, according to the Central Pacific Hurricane Center. Hurricane-force winds extend up to 30 miles from the center and tropical storm-force winds of 39 mph or more extend up to 140 miles, forecasters said. 

The Category 2 hurricane has prompted a high-surf advisory for the eastern shores of Oahu, Hawaii island, Kauai and Maui from noon Sunday through 6 p.m. Thursday. Forecasters warned that the surf will become life-threatening on Monday for eastern shores.

The latest five-day forecast has Guillermo as a tropical storm as it skirts just north of the Hawaiian islands Wednesday and Thursday.

“I would encourage people now to pick up some extra water, nonperishable goods, some things you would need in case the system is stronger than what is currently anticipated,” said Jon Jelsema, a senior forecaster with the Central Pacific Hurricane Center. “It certainly doesn’t hurt to have preparations in place … If it’s going to make a direct impact, there’s going to be stuff flying off the shelves and it might be too late … Even if you don’t use the supplies, it’s a long hurricane season.” 

Moderate to fresh tradewinds will continue through Monday, then weaken by Tuesday as Guillermo disrupts the flow, the National Weather Service said. 

Showers will increase as remnant moisture associated with former Tropical Depression 8E reaches the islands overnight and Sunday, with best chances of rain over windward and southeastern portions of the Big Island. 

The forecast for this week will be highly dependent on the eventual track of Guillermo, the agency said, but wet weather can be expected across the islands Tuesday night through Thursday night. A small craft advisory remains in effect for the waters south of Maui and Hawaii island until 6 p.m. Sunday, with east winds of 23 to 29 mph and seas of seven to 11 feet. 

In May, the Central Pacific Hurricane Center said there is a 70 percent chance of a busier-than-usual hurricane season, with five to eight storms. The normal season has four or five storms. 

Driving the activity in large measure is a persistent El Nino, associated with higher-than-normal sea surface temperatures in the eastern tropical Pacific. 

The hurricane season in the North Pacific lasts from June 1 to November 30. Two of Hawaii’s most destructive hurricanes, Iwa in 1982 and Iniki in 1992, came late in the season. 

The center warns that hurricanes not only pack high winds, but can also cause torrential rains that lead to flash flooding and abnormally high waves and storm surge. Each of these alone can pose a serious threat to life and property, the center said. 

Iniki’s high waves and storm surge, for instance, devastated the south shore of Kauai to elevations over 20 feet above sea level.

Meanwhile Friday, high temperatures tied records in Lihue and Kahului. The high in Lihue was 88 degrees, tying the record set for that date in 2008; the high in Kahului was 92, tying the record set in 1997.