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

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?

Hurricane Erin has been downgraded to a Category 3 hurricane but is gaining in size and raising the risk of life-threatening surf later this week along the U.S.

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

Hurricane Erin has weakened slightly to a Category 4 storm while positioned northeast of Puerto Rico and is on course to brush along the U.S. East Coast.

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.

While Erin won't hit the U.S. directly, the storm's biggest impact on the East Coast will be along the Outer Banks of North Carolina, where coastal flood watches, tropical storm watches and storm surge watches are in effect. The storm surge could be as high as 4 feet.

Implications for the Leeward Islands: Residents and visitors in St. Thomas, St. John, St. Croix, Puerto Rico and the northern Leeward Islands should monitor this system throughout the week. Even if the wave remains weak, increased moisture could bring showers, gusty winds and higher seas toward the end of the week.

Tropical Storm Erin is approaching Puerto Rico and the Virgin Islands, bringing heavy rains that could cause flooding and landslides

Tropical Storm Erin making its way across the Atlantic Ocean. What to consider for your Myrtle Beach vacation. August, September and October are the most active months of hurricane season.

Bill Kelly has the latest NEXT Weather forecast for the Philadelphia region on Tuesday night.