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

While Erin is expected to take a northward turn in the Atlantic, a new system off the coast of Africa has the National Hurricane Center's attention.

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.

Hurricane Erin weakened to a Category 3 storm with maximum sustained winds of 125 mph as its outer bands pounded the Virgin Islands and Puerto Rico with gusty winds and heavy rains early Sunday.

Hurricane Erin restrengthened into a Category 4 storm late Sunday, with forecasters warning it is expected to intensify and grow in size in the coming days as it lashes Caribbean

Tropical Storm Erin is likely to become Hurricane Erin shortly. It's now tracking over ocean water that's in the low 80s, and the dry and dusty air that has had a stranglehold on the circulation is dissipating.

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,