HONOLULU -- Hurricane Darby in the Central Pacific is expected to weaken over the next two days as it moves south of Hawaii's Big Island.
Darby, which was about 870 miles (1,400 kilometers) southeast of Hilo on Thursday, will weaken into a tropical storm as it moves south of the state on Saturday.
Forecasters said the storm, which had about 100 mph (155 kph) winds on Thursday, will rapidly lose power over the next 48 hours before becoming a post-tropical cyclone by Sunday.
There is no expected impact on land.
The National Weather Service said Darby was a small storm with hurricane-force winds extending 15 miles (24 kilometers) from the cyclone's eye and tropical storm-force winds extending up to 45 miles (72 kilometers) out.
The annual National Oceanic and Atmospheric Administration outlook predicted between two and four storms in the region for the year with a 60% chance of a below-average season.
The Central Pacific sees about four or five tropical cyclones on average annually and its season goes from June 1 until the end of November.
Officials said below-average sea temperatures associated with La Niña east of Hawaii are a factor.
La Niña is a natural cooling of parts of the equatorial Pacific that alters weather patterns around the globe. The opposite El Niño pattern creates above average ocean temperatures and has been present during some of the most active Pacific hurricane seasons, including in 2015 when there were 16 storms in the region.