The monster storm intensified to a Category 4 with 140 mph (225 kph) maximum sustained winds early Monday while it started to lash the Turks and Caicos Islands and the southeast Bahamas, according to the U.S. National Hurricane Center in Miami.

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 is expected to grow in size and strength as it moves north through the Atlantic this week. Forecasters expect it to pass well offshore of North Carolina on Wednesday and Thursday, but say it likely will cause coastal flooding and erosion, along with dangerous rip currents. National Hurricane Center

Erin strengthened again Monday as it began pelting part of the Caribbean with rain and wind before it’s expected to create dangerous surf and rip currents along the U.S. East Coast this week.