The National Weather Service issued a stern warning Friday afternoon to Key West residents that with the coming of Hurricane Irma they need to evacuate because "this is as real as it gets."

"Nowhere in the Florida Keys will be safe," the NWS Key West account said in a tweet in all caps. "You still have time to evacuate."

The tweet featured the latest statistics on the Category 4 storm, still ripping its way through the Caribbean and expected to make a direct hit on the Keys. As of 5 p.m. Eastern, Irma has 155 miles-per-hour sustained winds, just below the 157 mph threshold for a Category 5 storm.

Both are deemed "catastrophic" by the Saffir-Simpson Hurricane Wind Scale, which is used by the National Hurricane Center.

As residents of the Florida Keys were ordered to evacuate, Key West Mayor Craig Cates said this week "we're preparing for the worst." He said in a recent PBS interview that the Key West, which is at the end of a string of islands, or "Keys," extending from the southern tip of the Florida peninsula, haven't been hit by a hurricane in 11 years despite a couple close calls.

"But, before that, I think we were hit three times in one year. So, yes, we're definitely prepared for it," he said.

The NHC also issued its first official hurricane warnings for Florida late Thursday -- in South Florida and the Florida Keys -- as well as storm surge warnings which come with the "danger of life-threatening inundation from rising water moving inland from the coastline." NHC said the Keys face the threat of a storm surge of 5-10 feet. Hurricane conditions are expected in South Florida and the Keys by late Saturday, according to the latest advisory.

Florida Gov. Rick Scott said on Friday that all Floridians should be ready to evacuate as the state braces for Hurricane Irma, even if they are not in an evacuation zone. "We can expect additional evacuations as this storm continues to come up through the state," Scott said during a news conference. "I cannot stress this enough, do not ignore any evacuation orders. All Floridians should be prepared to evacuate."

He later urged all people in the Keys to "get out now."

National Weather Service Miami-South Florida meteorologist Andrew Hagen told the Washington Examiner that weather models expect Irma to be a Category 4 when it makes landfall, and though factors like land interaction and increasing wind shear will weaken the storm as it heads north, it will likely be at least a Category 1 hurricane when it gets near the Florida-Georgia line Monday morning.

President Trump has approved emergency declarations for Florida, South Carolina, Georgia, Puerto Rico and the Virgin Islands.

At least 23 deaths have reportedly been tied to Irma, and there has been reports of widespread damage and power outages due to wind and rain in islands along its path, including Cuba, the Bahamas, Barbuda, Puerto Rico, the Dominican Republic, Turks and Caicos, and St. Martin.