Tropical Storm Colin was poised to make landfall on Florida's Gulf Coast Monday night, bringing 50 mph winds, torrential rain, flooding across the state and possible tornadoes.
In an 11:00 p.m. ET statement, the National Hurricane Center said the storm's center was 70 miles from the state's Big Bend region, on the Gulf Coast, and was expected to dump as much as 10 inches of rain in parts of Florida, Georgia and the Carolinas through Tuesday.
Earlier, Florida Gov. Rick Scott declared a state of emergency in 34 counties, saying on Twitter: "Every Florida family and visitor needs to prepare now."
With the possibility of 12-foot waves, the Coast Guard urged boaters to stay out of the water until Tuesday, NBC Miami reported, and under the state of emergency, 6,000 National Guard soldiers were ready to be deployed, the governor said in a statement Monday.
Nine counties closed or postponed classes, after-school activities and, at two Tampa-area schools, graduation ceremonies. Several colleges also closed early, and one Gulf Coast county issued voluntary evacuations for residents living in low-lying areas, the Weather Channel reported.
Amid worsening winds, officials also closed the Sunshine Skyway Bridge spanning Tampa Bay.
"On the forecast track, the center of Colin will move onshore in the Florida Big Bend area shortly, then move across northern Florida and southeaster Georgia through early Tuesday morning, and move near or over the southeaster coast of the United States Tuesday," the National Hurricane Center said in the statement. "However, it's important to note that the strongest winds and heaviest rains are well removed from the center."
The Tampa Bay area was among the hardest hit. As of 11:00 p.m. ET, more than 4,000 Tampa Electric customers were without power. Earlier in the day, police chased drifting boats that had been knocked free by powerful waves, NBC affiliate WFLA reported, and officials there worried about the surging tide obliterating an erosion control project.
Just north, in Manatee County, coastal homeowners nervously watched docks disappear under a rising canal.
"The water is not supposed to be this high," Gail Greenfelder, of Anna Maria Island, told the station, adding: "It's actually a bit sobering because we're thinking about this is only [as] a tropical storm and what if we get a hurricane?"
By early Monday afternoon, photos taken in a community near St. Petersburg showed streets already deluged with water.
Flash floods pose the greatest threat, with the worst of the storm scheduled to come on late Tuesday, flooding could cause severe trouble for residents when local waterways already filled with rain are combined with the high tide.
Colin is the latest in a series of severe weather events across the country, from record-breaking heat in the West to flooding in Texas and storms that are expected to cause problems in the nation's capital and mid-Atlantic region.
Although the 2016 Atlantic hurricane season began five days ago, Colin is the third storm of the year.