Weather update #1: Tropical storm southeast of Hawaiian Islands strengthens to hurricane

5 a.m. update Monday: Tropical Storm Iona quickly strengthened into a hurricane.

As of 5 a.m., the center of Hurricane Iona was 895 miles southeast of Honolulu, moving west at 10 mph, according to the National Hurricane Center.

This motion is expected to continue with a gradual increase in forward speed during the next couple of days.

Maximum sustained winds have increased to near 75 mph with higher gusts. Additional strengthening is forecast over the next day or two. Gradual weakening is expected to begin around midweek.

According to forecasters, hurricane-force winds extend outward up to 15 miles from the center and tropical-storm-force winds extend outward up to 70 miles.

Big Island Now will provide hurricane updates as more information develops.

Original post: A tropical depression One-C, has upgraded to a tropical storm and is now 960 miles southeast of Honolulu.

According to the National Weather Service in Honolulu, Tropical Storm Iona is moving west with maximum sustained winds near 40 mph with higher gusts. Steady strengthening is forecast during the next couple of days.

Tropical storm force winds extend outward up to 35 miles from the center.

A low-pressure area has also formed east-southeast of the Hawaiian Islands. While the associated thunderstorm activity is currently disorganized, gradual development of this system is possible during the next couple of days while it moves generally westward at 10 mph.

According to the weather forecasters, the chances it will form into a cyclone over the next 48 hours are 40%.