Hurricane Michael, an extremely dangerous storm that shot up the Gulf Coast this week, made landfall Wednesday afternoon over the Florida Panhandle as one of the most powerful hurricanes on record to ever hit the U.S.

Authorities emphatically warned locals still in the area to hunker down as the major Category 4 storm encroached.

"THIS IS A WORST CASE SCENARIO for the Florida Panhandle!! Listen to your local emergency officials. Stay Inside & Survive!" National Weather Service Director Louis Uccellini said with landfall imminent.

Landfall of the storm's eyewall occurred just after 1:30 p.m. ET, just northwest of Miami Beach, about a two hour's drive from the state capital of Tallahassee.

Meteorologist onlookers have noted the extreme low pressure of the system, denoting a powerful hurricane. Stu Ostro of the Weather Channel tweeted: It's getting real -- and surreal -- as the eyewall of one of the strongest hurricanes on record to hit the U.S. moves onshore."

With a central pressure at 919 millibars just before landfall, the storm was stronger than Hurricanes Andrew and Katrina when they made landfall. Meteorologists said that Michael was the third-most powerful storm on record to strike the U.S. in terms of pressure, behind only the Labor Day hurricane in 1935 and Camille in 1969. In terms of wind speed, Michael is the strongest storm to hit the continental U.S. since Andrew in 1992.

A Category 4 hurricane, which according to the Saffir-Simpson Hurricane Wind Scale is capable of "catastrophic" damage, hasn't made landfall over the continental U.S. since 1954.

Republican Florida Gov. Rick Scott declared a state of emergency over the weekend and ordered mandatory evacuations in counties along the panhandle. By Wednesday morning, Scott said the time to evacuate had "come and gone" and any stragglers would need to seek refuge.

"First responders will not be able to come out in the middle of the storm. If you chose to stay in an evacuation zone, you must SEEK REFUGE IMMEDIATELY," he tweeted.

At least 2 million people had been pressed to evacuate, while 4 million people were under hurricane warnings.

President Trump declared a state of emergency for Florida on Tuesday, unlocking federal resources, and has tweeted that the government is ready to help.

The National Hurricane Center reported Wednesday afternoon that Michael had sustained maximum winds of 155 miles per hour, making it a "major" Category 4 storm (2 mph short of Category 5), with the potential for stronger wind gusts. Ahead of landfall, heavy rain, storm surge, and strong winds were already lashing out at Florida and nearby states.

The rapid strengthening of Michael caught some forecasters by surprise this week, as it only had become a hurricane Monday.

The hurricane-force danger will remain even after landfall. "Although steady weakening is predicted once the hurricane moves inland, the core of Michael will bring hurricane-force winds well inland over the Florida Panhandle, southeastern Alabama, and southwest Georgia," the National Hurricane Center said in a discussion post.

Meanwhile life-threatening storm surges could reach up to 13 feet in some areas and the potential for flooding will be a lingering issue afterwards.

In Florida's Gulf Coast, Michael threatens as much as $13.4 billion, according to property analytics service CoreLogic.

The latest hurricane to hit the U.S. comes a little more than a month after Hurricane Florence made landfall over the Carolinas and caused an immense amount of devastation with a deluge of rain and flooding.