The storm will remain a major hurricane through the middle of the week, according to the National Hurricane Center.

Royal Caribbean's Vision of the Seas made an unplanned stop in Port Canaveral due to Hurricane Erin. FOX 35's Matt Trezza learned that passengers were informed of the itinerary change just days before docking.

Storms that ramp up so quickly complicate forecasting and make it harder for government agencies to plan for emergencies. Hurricane Erick, a Pacific storm that made landfall June 19 in Oaxaca, Mexico, also strengthened rapidly, doubling in intensity in less than a day.

As of 5 a.m. on Sunday, Hurricane Erin has weakened back to a Category 3 storm but has grown larger, the National Hurricane Center said.

Hurricane Erin, after strengthening into a Category 5 storm early Saturday, weakened to Category 3 by Sunday morning and has taken a track slightly more south than originally forecast, the National Hurricane Center said.

Even when they don't brush the coast or make landfall, such storms can be deadly and cause millions of dollars of damage. Erin is expected to remain hundreds of miles offshore, according to the National Hurricane Center,