The storm has already prompted evacuation orders on North Carolina's Outer Banks and warnings about dangerous rip currents and swells along the East Coast.

The Ocean City Beach Patrol has closed the ocean to swimming, wading and surfing Tuesday as tropical storm activity off the coast brings dangerous conditions to the resort town.

Two more tropical systems trail Hurricane Erin, which is following a projected course that brushes past the East Coast without making landfall.

While Tropical Rainstorm Erin continues to generate rough surf and coastal hazards, AccuWeather meteorologists are monitoring additional tropical waves near the region where Erin initially formed earlier this month.

Forecasts nudge Erin's likely path to the west, increasing the risks at U.S. beaches. Experts say the storm's massive size, rather than windspeed, is what makes it a threat.

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

Most of Erin’s intensification occurred during a 12- to 15-hour window overnight, according to Dan Pydynowski, a meteorologist at AccuWeather. By 5 p.m. Friday, Erin’s winds had remained only 75 mph.

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.