(RNN) - Florida Gov. Rick Scott pleaded to residents to take shelter Hurricane Michael took aim at the Florida Panhandle Wednesday.
Maximum sustained winds were near 150 miles an hour as the monstrous storm quickly approached landfall. A Category 5 storm has sustained winds of 156 mph.
"We expect conditions across the panhandle to deteriorate rapidly," Scott said. "The storm is here, it's not safe to travel across the Panhandle. If you are in a coastal area, do not leave you house. The time to evacuate has come and gone."
The storm strengthened to a Category 4 hurricane early Wednesday, giving it the potential to be the first hurricane of that category or higher to make landfall in the Florida Panhandle, likely near Panama City.
In contrast, Hurricane Katrina made landfall in Southeast Florida on Aug. 25, 2005, as a Category 1 hurricane with winds of 80 mph. The storm moved west across south Florida and into the Gulf of Mexico where it intensified into a Category 5.
Katrina eventually weakened to a Category 3 (sustained winds of 125 mph) before making landfall in southeast Louisiana and the Mississippi Gulf Coast, devastating large portions of New Orleans in the process.
Just a few weeks ago, Hurricane Florence made landfall on Sept. 14 near Wrightsville Beach, NC. The storm had maximum sustained winds of 90 mph, the National Hurricane Center said.
The hurricane, which has maximum-sustained winds of 150 mph, could strengthen even further, hours before its forecast landfall Wednesday afternoon, according to the National Hurricane Center. Officials worry the storm surge could be deadly, reaching 14 feet in some areas.
"The situation is about to get serious in parts of Bay, Gulf, and Franklin county," the National Weather Service in Tallahassee tweeted at 11:19 a.m. ET. "We've issued our first ever Extreme Wind Warning. This means wind gusts in excess of 130 MPH are expected as #HurricaneMichael makes landfall in the next few hours. Shelter in place IMMEDIATELY."
Scott said in a tweet that "the time for evacuating along the coast has come and gone."
He announced Tuesday that 54 shelters were opening across the state in preparation.
In Tallahassee, police warned residents to get inside and stay there.
"Do not get out and drive in the storm," Tallahassee Police tweeted. "Stay inside after the storm has passed so we can evaluate the safety of our community and identify hazards."
In nearby Walton County, emergency management suspended its services as the storm approached.
NHC Director Ken Graham said Apalachicola County is already seeing powerful winds. He warned a storm of this magnitude could potentially knock power out for weeks in areas.
Graham warned Michael is expected to stay a hurricane as it goes into central Georgia overnight. Storm surges could be seen as far south as the Tampa-St. Petersburg area.
In its 12 p.m. ET update, the NHC said Michael was located 40 miles south of Panama City, FL, and was moving north at 14 mph. Tropical storm winds extend out 185 miles from the center of the storm.
Residents of 13 Florida counties along the Panhandle and the west coast have been issued mandatory evacuation orders. Nine other counties have been issued voluntary or phased evacuation orders.
The evacuation orders affect at least 2 million people, CNN reports.
Many businesses in Panama City Beach, FL, were reportedly shuttered Tuesday evening as Michael neared.
Mandatory evacuations have been ordered for the following Florida counties: Bay, Citrus, Dixie, Franklin, Gadsden, Gulf, Jackson, Jefferson, Levy, Okaloosa, Taylor, Wakulla and Walton.
Voluntary or phased evacuations have been issued for these Florida counties: Calhoun, Hernando, Leon, Liberty, Madison, Pasco, Santa Rosa, Washington and Escambia.
Those in mobile homes or other weak structures in particular were urged to leave. Tolls were suspended in order to help people evacuate.
Residents stocked up on food, water and gasoline. Some gas stations in the Panhandle ran out of fuel Tuesday as demand surged, WKMG reported. Officials from AAA said fuel trucks were operating nonstop to keep the stations supplied.
By Monday morning, generators were sold out in many Tallahassee-area stores, according to the Tallahassee Democrat.
Michael is expected to produce a life-threatening storm surge for much of Florida and potentially Alabama's coastlines. More than 325 miles of coastline from Mobile, AL, through the Florida Panhandle and Big Bend area are threatened, according to the National Weather Service.
Water levels began rising Tuesday.
A storm surge warning is in effect from the Okaloosa-Walton County line to the Anclote River in Florida, and a storm surge watch is in effect for the Anclote River to Anna Maria Island, including Tampa Bay.
Tropical storm-force winds extend up to 175 miles outward from the storm's center, and hurricane-force winds extend outward up to 45 miles from the center.
After making landfall, Michael is expected to cut a path across the Southeast through Thursday night before heading north-eastward.
Widespread power outages, major tree damage and structural damage are expected in the Panhandle, with some of this damage extending as far as parts of northern Georgia and North and South Carolina, the Weather Channel reports.
These states may also see tornadoes spawn Wednesday into Thursday.
The Carolinas are still recovering from Hurricane Florence, which hit the states with devastating rain and flooding in September.
President Donald Trump approved an emergency declaration for Florida Tuesday, meaning federal aid will be available to the state to assist in hurricane recovery.
Scott first declared a state of emergency Sunday, then expanded it the next day to include 35 counties.
"Hurricane Michael is forecast to be the most destructive storm to hit the Florida Panhandle in decades," Scott said. "You cannot hide from storm surge, so get out if an evacuation is ordered."
The governors of Alabama and Georgia also declared states of emergency because of the expected effects of the storm on those states.
Heavy rainfall could produce life-threatening flash flooding from the Florida Panhandle and Big Bend region into parts of Georgia, the Carolinas and southeast Virginia.
About 3.7 million people are under hurricane warnings across Florida, Alabama and Georgia, while tropical storm warnings cover 8.5 million people in several states, according to CNN.
A hurricane warning has been issued from the Alabama-Florida border to the Suwannee River.
Tropical storm warnings have been issued from the Alabama-Florida border to the Mississippi-Alabama border, from the Suwanee River to the Chassahowitzka River in Florida and from north of Fernandina Beach, FL, to Surf City, NC.
A tropical storm watch is in effect along the southeastern coast of the U.S. and beyond, from the Chassahowitzka River to Anna Maria Island in Florida, including Tampa Bay, the Mississippi-Alabama border to the mouth of the Pearl River, Surf City, NC, to Duck, NC, and for the Pamlico and Albemarle Sounds.
The Florida Panhandle and Big Bend areas, in addition to southern portions of Alabama and Georgia, are expected to receive as much as 12 inches of rain through Friday.
The rest of Georgia, the Carolinas and southern Virginia are expected to receive as much as 8 inches.
These rains could bring life-threatening flash flooding.
The Florida Peninsula, eastern mid-Atlantic and southern New England coast could see as much as 3 inches of rain.
Michael is expected to weaken after making landfall and as it moves across the Southeast before reaching Virginia and Maryland Thursday night or Friday. Forecasters expect Michael to re-emerge over water and head away from the U.S. on Friday.
The last major hurricane to hit northwest Florida was in 2005, when Hurricane Dennis made landfall at Santa Rosa Island, FL, as a Category 3 storm, the Northwest Florida Daily News reported.
The seventh hurricane and second major hurricane of the 2018 Atlantic hurricane season, Michael formed near Mexico's Yucatan Peninsula on Sunday.
Michael brought heavy rains to western Cuba as it moved through the area Monday. At least 13 people in Central America died as a result of the storm's rain and flooding over the weekend, Al Jazeera reported.
Florence, the first major hurricane of the season, made landfall as a Category 1 storm the morning of Sept. 14 at Wrightsville Beach, NC.
It left at least 51 people dead across North Carolina, South Carolina and Virginia, according to Reuters. The amount of damage, particularly from flooding associated with the storm, is expected to reach 11 figures.
Meanwhile, Hurricane Leslie continues moving through the middle of the Atlantic.
The NHC announced in its 11 a.m. ET update that Hurricane Leslie was 1,130 miles southwest of the Azores, moving to the south at 10 mph. It's expected to travel south before turning to the east-northeast Wednesday night.
The storm has maximum sustained winds of 75 mph. There are no coastal watches or warnings in effect for Leslie.
In addition, Tropical Storm Nadine, the 14th named storm of the hurricane season, is strengthening, as of the 11 a.m. ET update.
Nadine is moving at 7 mph, with maximum-sustained winds of 65 mph.
It was located about 505 miles west-southwest of the Cabo Verde Island, an archipelago nation off the African coast. No coastal watches or warnings have been issued for Nadine.
The storm is expected to begin weakening Thursday.
Tropical Storm Nadine formed Tuesday morning.