Tropical Storm Hermine strengthened over the Gulf of Mexico early Thursday, and forecasters said they expected it to hit Florida with hurricane-force winds and a dangerous storm surge.
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If Hermine makes landfall as a category one hurricane, as expected, it will be the first in Florida in 11 years, since Hurricane Wilma struck the sunshine state in 2005.
The storm churned over warm Gulf waters, packing 60 mph winds that extended for some 125 miles, as forecasters issued a hurricane watch for a section of Florida's Gulf Coast that stretched from the northern outskirts of Tampa to the coastal area south of Pensacola.
Dangerous rip currents, high seas and minor coastal flooding threaten an even larger area of Florida's coast.
Dozens of Tampa-area schools and government offices announced closures on Wednesday night as the city braced for the storm's impact on Thursday.
The National Hurricane Center is expecting winds of 74 mph or greater when the storm makes landfall on Thursday night.
Although the full force of the storm isn't expected to reach land until after nightfall, tropical winds will begin gusting up to 40 mph Thursday afternoon, complicating any last-minute storm planning.
"Preparations to protect life and property should be rushed to completion," the forecast said.
In addition to the hurricane-force winds, forecasters said the storm could bring "life-threatening inundation within the next 36 hours along the Gulf coast of Florida."
Storm surges may reach as high as 7 feet, while the region will be blanketed with 5 to 10 inches of rain, with maximum amounts of as much as 20 inches falling in isolated areas.
Also, the system will increase the risk of tornadoes near the central Florida coast.
"The tornado risk will increase through Thursday and spread into north Florida and southeast Georgia," the Hurricane Center said.