The surge, or the rise in sea water above normally dry land along the coast, could reach at least 2.4m to 3.6m in the hardest-hit areas, inundating roads, homes and businesses.
"On the forecast track, the core of Michael will move across central and eastern Georgia this morning, and then over southern and central SC later today".
Michael will move northeastward across the southeastern USA through Thursday night, and then move off the Mid-Atlantic coast away from the United States on Friday.
A man was killed by a tree that crashed into his home in Gadsden County, Florida on Wednesday, as Hurricane Michael plowed into Alabama and Georgia, leaving behind a path of destruction in the Panhandle.
Just a few miles to the east of Panama City Beach lies the tourist town of Mexico Beach, which took a direct hit. On Twitter, the National Weather Service said, in all caps, "THIS IS A WORST CASE SCENARIO".
Michael is continuing to strengthen as its minimum central pressure has dropped to 919 millibars. I urge all Floridians in the Panhandle to continue sheltering in place, and listening to local authorities.
National Hurricane Center Meteorologist Dennis Feltgen said: "We are in new territory".
Up the coast in Pensacola, the water temperature is 82 degrees Fahrenheit (28 degrees Celsius) - 8 degrees Fahrenheit (4.4 degrees Celsius) higher than normal for this time of year. And so far, Hurricane Michael's pressure ranks as the third-lowest for any hurricane to strike the US mainland, at 919 millibars.
Mike Thomas, the mayor of Panama City Beach, a resort west of Panama City, said he expected there would be casualties and that emergency personnel would not go out when winds get over 80km/h. She spoke from the parking lot of a wrecked gas station in Walton County, tilting the camera to show the damage around her.
Michael hit Florida with wind speeds of 155 miles per hour (250 kilometers per hour), placing it nearly into Category 5 scale, which starts at 157 mph. "This is going to have structure-damaging winds along the coast and hurricane force winds inland".
According to an 11:30 a.m. advisory from the National Hurricane Center, the storm with the potential to create a catastrophic event across Northwest Florida, had winds measured at 150 miles per hour based on data from Air Force Reserve Hurricane Hunter aircraft.
Meteorologists offered stark warnings ahead of Wednesday's landfall. "The historical record, going back to 1851, finds no Category 4 hurricane ever hitting the Florida panhandle".
The lower the air pressure, the less air molecules there are.
A prediction of peak gusts in S.C. shows 45 miles per hour winds impacting Aiken, only slightly weakening to 40 miles per hour when they reach Columbia, according to the NWS.
The storm made landfall northwest of Mexico Beach around noon on Wednesday, with an eye so clear and wide it could easily be seen from space.