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

Hurricane Erin is a sprawling Category 4 storm churning in the Atlantic Monday after exploding in strength at a historic rate this weekend. The storm’s enormous footprint is becoming the biggest concern.

The outer bands of powerful Hurricane Erin lashed Puerto Rico, and the storm is approaching the Bahamas next. What can the mainland U.S. expect?

Additional strengthening is expected as the storm is forecast to “remain a large and dangerous major hurricane through the middle of this week,” the National Hurricane Center said.

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.

Forecasters said Erin should begin to slowly weaken as it increased wind shear. However, it's predicted to remain a major hurricane until late next week.

Hurricane Erin has been downgraded to a Category 3 hurricane. A tropical storm warning is in effect for the Turks and Caicos Islands as winds and heavy rains continue to lash the Virgin Islands and Puerto Rico.