Updated 5:00 pm EDT

People across Florida were given notice Sunday that Hurricane Milton is expected to intensify rapidly into a major hurricane before slamming midweek into the storm-ravaged Gulf Coast.

While forecast models vary widely, the most likely path suggests Milton could make landfall Wednesday in the Tampa Bay area and remain a hurricane as it moves across central Florida into the Atlantic Ocean, forecasters said. That would largely spare other southeastern states ravaged by Hurricane Helene, which caused catastrophic damage from Florida into the Appalachian mountains and a death toll that rose Sunday to 230 people.

Florida’s governor, Ron DeSantis, said Sunday that while it remains to be seen just where Milton will strike, it’s clear that Florida is going to be hit hard — “I don’t think there’s any scenario where we don’t have major impacts at this point.”

“You have time to prepare — all day today, all day Monday, probably all day Tuesday to be sure your hurricane preparedness plan is in place,” the governor said. “If you’re on that west coast of Florida, barrier islands, just assume you’ll be asked to leave.”

The St. Petersburg-Tampa Bay area is still cleaning up extensive damage from Helene and its powerful storm surge. Twelve people perished as Helene swamped the coast, with the worst damage along the narrow, 20-mile string of barrier islands that stretch from St. Petersburg to Clearwater.

Mr. DeSantis expanded his state of emergency declaration Sunday to 51 counties, and said Floridians should prepare for more power outages and disruption, making sure they have a week’s worth of food and water and are ready to hit the road. The Federal Emergency Management Agency, meanwhile, coordinated with the governor and briefed President Biden Sunday on how it has staged lifesaving resources.

“I highly encourage you to evacuate” if you’re in an evacuation zone, said Kevin Guthrie, executive director of the Florida Division of Emergency Management. “We are preparing … for the largest evacuation that we have seen, most likely since 2017, Hurricane Irma. “

The state has prepared emergency fuel sources and EV charging stations along evacuation routes, and “identified every possible location that can possibly house someone along those routes,” Mr. Guthrie said. People who live in homes built after Florida strengthened its codes in 2004, who don’t depend on constant electricity and who aren’t in evacuation zones, should probably avoid the roads, he said.

All classes and school activities in St. Petersburg’s Pinellas County preemptively closed Monday through Wednesday as Milton approached, and Tampa opened city garages for free so people could park their cars safe from the next floodwaters.

As many as 4,000 National Guard troops are helping state crews to remove debris, Mr. DeSantis said, and he directed that Florida crews dispatched to North Carolina in Helene’s aftermath return to the state to prepare for Milton.

“All available state assets … are being marshaled to help remove debris,” Mr. DeSantis said. “We’re going 24-7 … it’s all hands on deck.”

U.S. Air Force hurricane hunters confirmed that Milton was centered about 815 miles west-southwest of Tampa Sunday afternoon, with maximum sustained winds of 80 mph, the hurricane center said.

The hurricane center said Mexico’s Yucatan peninsula, the Florida Peninsula, the Florida Keys and the northwestern Bahamas should monitor the system’s progress. Heavy rainfall was expected Sunday ahead of the storm itself, and will likely then combine with Milton’s rainfall to flood waterways and streets in Florida, where forecasters said up to a foot of rain could fall in places through Wednesday night.