KEY LARGO, Fla. — South Florida residents breathed a sigh of relief early today after Tropical Storm Ernesto confounded forecasters by lumbering ashore without the hurricane-strength winds that had once been feared.

Ernesto lost much of its punch crossing mountainous eastern Cuba. It made landfall late Tuesday on Plantation Key with 45-mph winds, far from the 74-mph threshold for a hurricane that Ernesto briefly met Sunday.

"Fortunately it didn't get too big," said David Rudduck of the American Red Cross. "It was the little train that couldn't."

Forecasters said Ernesto could weaken to a tropical depression later today, but rainbands could dump as much as 10 inches of rain in some spots along Florida's east coast.

At a bar in Key Largo, transplanted New Yorker Brian Lima nursed a beer while he watched the rain fall. "I've seen much worse rainstorms in New York," Lima said.

Ernesto was forecast to move up the middle of Florida and exit on the northeast coast by early Thursday before hitting the mainland again in Georgia or the Carolinas.

"How much strengthening occurs after Ernesto emerges into the Atlantic depends on how much of a cyclone is left," said senior hurricane specialist James Franklin.

A tropical storm warning was in effect from Bonita Beach, on Florida's west coast, around the peninsula and Keys and up the entire eastern length of Florida to Altamaha Sound, Ga., about halfway up that state's coast. A hurricane watch was in effect from the Savannah River, Ga., northward to Cape Fear, N.C.

"The best-laid plans can be disrupted by Mother Nature, in the event this storm were to stall out over the warm waters of the Gulf Stream and intensify," South Carolina Gov. Mark Sanford warned.

Some people, such as North Carolina forecaster Ryan Boyles, welcomed the possibility of a good soaking. "The ground is dry, the streams are low and the reservoirs are down," he said.

At 5 a.m., the center of the storm was about 45 miles west-southwest of Miami and moving north-northwest near 8 mph. Ernesto still had top sustained winds of 45 mph.

"This does not look like a catastrophic event, but we always want to be ready," Homeland Security Secretary Michael Chertoff said in Tallahassee. He attended Hurricane Katrina anniversary events earlier in the day in Louisiana and Mississippi.