Hurricane Irene, already a 120-mph powerhouse with tropical storm winds 230 miles from its center, was turning toward North Carolina's Outer Banks late Wednesday en route to a very wet and potentially dangerous weekend encounter with Maryland's Eastern Shore.
Irene will likely produce periods of torrential rain when it arrives, with totals of 4 to 6 inches or more anywhere from Ocean City to Baltimore and the rest of Central and Southern Maryland, forecasters said.
"The margin of error is still quite large," said National Hurricane Center spokesman Dennis Feltgen. "Everyone from the Carolinas to New England needs to be paying attention to this."
The forecast calls for up to an inch of rain in Central Maryland today as a cold front approaches the region. That rain, which follows several weeks of thunderstorms, is unrelated to Irene. But it will increase the risk of flooding when Irene does arrive.
"The rain has saturated the ground, so if you're adding more water … the water has nowhere to go but up," with flooding, Feltgen said. "And it makes it much easier for trees to come down with the wind."
And with the downed trees come downed power lines. Public officials urged Marylanders to begin storm preparations, gather up the supplies needed to get them through extended power outages and monitor weather forecasts.
Ocean City officials also urged residents and visitors to secure loose objects, such as trash cans and lawn furniture. People were also making arrangements to protect their boats in the resort town.
The National Hurricane Center said late Wednesday that the center of the storm was about 200 miles southeast of Nassau in the Bahamas, moving to the northwest at 12 mph.
Top sustained winds were estimated at 120 mph, but forecasters expect Irene to strengthen further before reaching the Outer Banks, perhaps reaching Category 4 status, with top winds of 131 mph or higher.
Evacuations were under way in Ocracoke, the most exposed of the Outer Banks' barrier islands.
In the Bahamas, Irene was dropping 6 to 12 inches of rain, with a storm surge 7 to 11 feet above normal tides.
The island was as buttoned-down as possible, but those who did not leave faced "a really tough time," said NHC Director Bill Read.
Irene's rains were blamed for two deaths in the northeast Caribbean. A woman in Puerto Rico and a Haitian man in the Dominican Republic were swept away by floodwaters.
Although the latest forecast storm track takes Irene offshore as it passes the Outer Banks and Delmarva, the storm's effects would still be felt well inland, Feltgen said.
Irene is a big storm. Hurricane-force winds extended up to 60 miles from the storm's center, and tropical storm winds were found 230 miles out.
"Even though the center could stay 100 miles offshore, tropical storm impacts could be felt inland," Feltgen said. Asked if that could include Central and Southern Maryland, he said, "Absolutely."
Irene is forecast to be off the mouth of the Chesapeake Bay by 2 a.m. Sunday, and off Ocean City by 8 a.m.
Tropical storm conditions are possible Saturday through Sunday in Ocean City. In addition to the heavy rain, high winds and flooding, Feltgen said, those who elect to stay on the barrier islands should expect "beach erosion, rip currents and very heavy surf."
From Delmarva, the center of the forecast track would take Irene north, across eastern Long Island and into the center of New England.
The storm's path reminds forecasters of Hurricane Floyd, which passed over Ocean City in September 1999 on its way to New England.
The big difference, Feltgen said, was that Floyd was "dying a quick death. This one [Irene] may hold its hurricane strength all the way into New England."
Floyd was bad enough. Its wind and rain cut off power to almost half a million Marylanders, some for days. The slow return to normalcy prompted then-Gov. Parris N. Glendening to order utility regulators to investigate Baltimore Gas & Electric Co.'s emergency response plans.
More than 750 trees were toppled in Baltimore alone. Severe flooding struck Elkton, North East and Crisfield. Hundreds of roads were closed. There were sewage spills, and one death was attributed to the storm.
Glendening later sought federal disaster assistance for 11 counties.
Reuters contributed to this article.