Hurricane Erin is now a Category 4 storm, rapidly intensifying overnight into early Saturday morning as it moves closer to the U.S. East Coast with sustained winds up to 155 mph.

SAN JUAN, Puerto Rico (AP) — Hurricane Erin exploded in strength to a Category 5 storm in the Caribbean on Saturday, rapidly powering up from a tropical storm in a single day, the National Hurricane Center said. While the compact hurricane’s center wasn’t expected to hit land, it threatened to dump flooding rains as it continued to grow larger.

While a Gulf disturbance that moved into Texas on Friday seems to have run its course, Hurricane Erin in the western Atlantic intensifies.