Erin is a large hurricane and is expected to grow "substantially in size" as it moves over the western Atlantic this week, according to the Hurricane Center. Hurricane-force winds extend outward up to 80 miles from the center, and tropical-storm-force winds extend outward up to 205 miles.

Tropical Storm Keli, meanwhile, was located about 795 miles southeast of Honolulu with maximum sustained winds near 40 mph and higher gusts. Keli was moving west at 15 mph and is expected to maintain that general motion over the next couple of days.

HONOLULU (AP) — Iona strengthened to a Category 3 hurricane several hundred miles south-southeast of Hawaii, but poses no threat to the islands, forecasters said Tuesday. Iona is one of two major weather systems in the central Pacific Ocean. This ...

Erin is a category 3 major hurricane with winds of 115 mph and is located approximately 750 miles south-southeast of Cape Hatteras as of Tuesday morning.

A hurricane's category only measures wind speed, not how far those winds extend from the center. The size of a storm's wind field is crucial for predicting storm surge and overall reach.

Hurricane Erin is pelting parts of the Caribbean and is forecast to create dangerous surf and rip currents along the U.S. East Coast this week.