Tropical storm Alberto weakened as it moved slowly toward Florida's coast today, although forecasters said it could still become the year's first hurricane before reaching shore.
The storm's center was still over the Gulf of Mexico at 2am EDT (7am Irish time), but heavy winds and rains were lashing Florida, where officials had ordered thousands of residents to evacuate barrier islands, flood plains and trailer parks.
At 2am, Alberto's center was about 140 km west-southwest of Cedar Key, on Florida's west coast, and moving northeast near 17 kph, the US National Hurricane Center said.
Its maximum sustained winds had slowed to near 105 kph, below the 119 kph threshold at which tropical storms become hurricanes.
But forecasters said it could still strengthen before its center moved over Florida later today and a hurricane warning remained in effect for much of the state's west coast.
"This is still strong enough to cause some significant damage," US National Hurricane Center director Max Mayfield told CNN.
"We don't want to overdo this but we sure don't want to underdo it either." Florida Governor Jeb Bush declared a state of emergency even though the most likely area of landfall was sparsely populated swampland and farming country, with no big cities like New Orleans, devastated in August by Hurricane Katrina.
Florida officials said 26 shelters in 16 counties had been opened for evacuees. "This is a serious storm and we are taking it seriously," Mr Bush said. "We're not dealing with large numbers of people. But given the storm surge we anticipate and given the velocity of these winds, I hope people aren't being defiant."