The Florida Keys will begin to see some rain from the outer bands of this depression late Sunday and into Monday with totals reaching 2 to 4 inches.
Wind gusts in central North Carolina could reach 40 miles per hour.
A hurricane center graphic showed the disturbance gaining storm-level winds of over 39 miles per hour on Monday and maintaining those speeds as it potentially hits the Florida coast east of Pensacola on Wednesday. The storm was about 140 miles (230 kilometers) south-southwest of the western tip of Cuba as of Sunday evening.
An Air Force hurricane hunter airplane was sent into the storm to investigate, the hurricane center said.
Tropical Storm Michael is expected to make landfall this week across the Florida Panhandle before moving up into Georgia and the Carolinas, dropping up to 3 inches of rain in parts of the Triangle late Wednesday into Thursday.
By declaring this state of emergency, Governor Scott is ensuring that state and local government has ample time, resources and flexibility to get prepared for this storm. Michael could become a hurricane by Tuesday night or Wednesday, the NHC said in a Sunday afternoon advisory.
Residents of Florida's Panhandle frantically filled sandbags, boarded up homes and secured boats Monday as they anxiously awaited Hurricane Michael, which forecasters warned could smash into the state's Gulf Coast as a risky major hurricane within days.
Scott also activated 500 members of the Florida National Guard ahead of the storm.
The "risk of unsafe storm surge, rainfall, and wind impacts continues to increase", the National Hurricane Center warned Sunday. The Hurricane Center's statement said interests along the northeastern and central U.S. Gulf Coast should monitor the progress of the depression.
Broad low pressure, centered to the south and east of the Yucatan as of Saturday morning, will gradually work northward into the Gulf of the Mexico through Sunday and into Monday.
Tropical storm warnings are in effect for Mexico's Yucatan Peninsula, including Cancun, and western Cuba, where tropical storm conditions will develop overnight. The National Hurricane Center is forecasting a high probability of tropical development at 100%.
Scott has suspended his U.S. Senate campaign for the "next few days" to oversee response to Michael, CNN reported Sunday night.