The warning is to be issued for the smallest area possible, and be valid for times of two hours or less, though some warnings have been issued for three hours. Showers and storms are expected to stick around through Friday, with some sunny conditions returning for the weekend.
State officials issued disaster declarations in Alabama and Georgia and the storm is also expected to bring heavy rainfall to North and SC. It is expected to weaken as it moves up into the southeastern United States.
The National Weather Service out of Tallahassee has posted a map showing a projected landfall at 1pm EST on Wednesday, along with current imagery of the storm's path. The risk of life-threatening storm surge, flooding rains, and risky winds are increasing for the northeastern Gulf Coast. A north-northwestward to northward motion is expected through tonight, followed by a northeastward motion on Wednesday and Thursday.
Ken Graham, director of the Miami-based National Hurricane Center, said Michael is "unfortunately, a historical and incredibly risky and life-threatening situation".
Forecasters said Michael's tropical-storm-force winds stretched 370 miles across, with hurricane-strength winds extending up to 35 miles from the center.
Hurricane-force winds extended up to 45 miles (75 kilometres) from Michael's centre at the height of the storm.
Hurricane Michael is now an extremely risky Category 4 hurricane as it barrels toward the northeastern Gulf Coast.
A fast and furious Hurricane Michael sped toward the Florida Panhandle on Tuesday with 120 miles per hour winds and a potential storm surge of 13 feet, giving tens of thousands of people precious little time to get out or board up.
Tropical Storm Michael Will Become a Hurricane Monday
In Alabama, Troy University and Wallace Community College in the southeastern part of the state canceled Wednesday classes. Maximum sustained winds have climbed to 90 miles per hour and the central pressure remains at 970 millibars.
During a news conference on Tuesday, Florida Gov. Rick Scott warned Michael is a "massive storm" that could bring "total devastation" to parts of the state. The minimum central pressure recently measured by the reconnaissance aircraft was 947 mb (27.97 inches).
Previous year saw a string of catastrophic storms batter the western Atlantic - including Irma, Maria and Harvey, which caused a record-equaling $125 billion in damage when it flooded the Houston metropolitan area.
King tides, the highest tides of the year, also could be a factor in water levels and they will be monitored.
The most powerful hurricane on record to hit Florida's Panhandle left wide destruction and wasn't almost finished Thursday as it crossed Georgia toward the Carolinas, still reeling from epic flooding in Hurricane Florence.
"The state is mobilizing all available resources to ensure public safety ahead of Hurricane Michael", Deal said. Jacksonville will experience tropical downpours and storms by Wednesday evening as the system makes landfall. This rainfall could lead to life threatening flash floods. Forecasters said it would unleash damaging wind and rain all the way into the Carolinas, which are still recovering from Hurricane Florence's epic flooding. Florida Peninsula, eastern Mid Atlantic, southern New England coast...1-3 inches. It's expected to send life-threatening surges of ocean water into coastal areas along the Gulf, from Pensacola around the coast to Tampa.
NEXT ADVISORY ----- Next intermediate advisory at 700 PM CDT.