Milton rapidly strengthened in the Gulf of Mexico on Monday and was forecast to become a Category 5 storm on a path toward Florida, threatening a dangerous storm surge in Tampa Bay and setting the stage for potential mass evacuations less than two weeks after a catastrophic Hurricane Helene swamped the coastline.

A hurricane warning was issued for parts of Mexico's Yucatan state, and much of Florida's west coast was under hurricane and storm surge watches. Florida's Lake Okeechobee, which often floods during intense storms, was also under a hurricane watch.

"This is the real deal here with Milton," Tampa Mayor Jane Castor said at a news conference. "If you want to take on Mother Nature, she wins 100 per cent of the time."

Milton was a Category 4 storm with maximum sustained winds of 250 km/h Monday morning over the southern Gulf of Mexico, the National Hurricane Center said. It was forecast to become a Category 5 storm later Monday with winds greater than 250 km/h and become a large hurricane over the eastern Gulf.

Its centre could come ashore Wednesday in the Tampa Bay area, and it could remain a hurricane as it moves across central Florida toward the Atlantic Ocean. That would largely spare other states ravaged by Helene, which killed at least 230 people on its path from Florida to the Appalachian Mountains.

Forecasters warned of a possible storm surge of 2.4 to 3.6 metres in Tampa Bay and said flash and river flooding could result from 13 to 25 centimetres of rain in mainland Florida and the Keys, with as much as 38 centimetres in places.

The Tampa Bay area is still cleaning up extensive damage from Helene and its powerful surge. Twelve people perished, with the worst damage along a 32-kilometre string of barrier islands from St. Petersburg to Clearwater.

WATCH | Milton hurdles toward Florida: 

Hurricane Milton strengthens to Category 4 as it closes in on Florida's west coast

Floridians in the path of Hurricane Milton have a fresh warning: hunker down, or get out. The storm is now a dangerous Category 4 as it roars towards Florida's west coast. The CBC's Marianne Dimain has more.

No time for red tape: DeSantis

Florida Gov. Ron DeSantis said Monday that it was imperative that messes from Helene be cleaned up ahead of Milton's arrival so they don't become dangerous flying projectiles. More than 300 vehicles picked up debris Sunday but encountered a locked landfill gate when they tried to drop it off. State troopers used a rope tied to a pickup truck and busted it open, DeSantis said.

"We don't have time for bureaucracy and red tape," DeSantis said. "We have to get the job done."

About seven million people were urged to evacuate Florida in 2017 as Hurricane Irma bore down. The exodus jammed freeways, led to long lines at gas stations and left evacuees in some cases vowing never to evacuate again.

Building on lessons learned during Irma and other previous storms, Florida is staging emergency fuel for gas vehicles and charging stations for electric vehicles along evacuation routes, Kevin Guthrie, executive director of the Florida Division of Emergency Management, said Sunday.

"We are preparing ... for the largest evacuation that we have seen, most likely since 2017, Hurricane Irma," Guthrie said. 

Milton's centre was about 240 kilometres west of Progreso, Mexico, and about 1,185 kilometres southwest of Tampa on Monday morning, moving east-southeast at 13 km/h, according to the hurricane centre.

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. 

Evacuations, closures, cancellations

On beaches in the St. Pete Beach area, where Helene's storm surge flooded homes and businesses, lifeguards removed beach chairs and other items Monday that could become projectiles in hurricane winds. Schools including the University of Central Florida in Orlando announced they would close in the middle of the week, and Walt Disney World said it was monitoring the hurricane but operating normally for the time being. 

All road tolls were suspended in western central Florida. The St. Pete-Clearwater International Airport said it would close after the last flight Tuesday. Hillsborough County, home to Tampa, ordered evacuations for all mobile and manufactured homes by Tuesday night.

All classes and school activities in Pinellas County, home to St. Petersburg, closed pre-emptively Monday through Wednesday. Officials in Tampa freed all city garages to residents hoping to protect their cars from flooding, including electric vehicles. The vehicles must be left on the third floor or higher in each garage.

The coastal Mexican state of Yucatan announced it was cancelling classes in most towns and cities along the coast, after forecasters predicted Milton would brush the northern part of the state. The cancellations included its most heavily populated Gulf coast cities, like Progreso; the capital, Merida; and the natural protected area of Celestun, known for its flamingoes.

It has been two decades since so many storms crisscrossed Florida in such a short period of time. In 2004, an unprecedented five storms struck Florida within six weeks, including three hurricanes that pummeled central Florida.

Although Tampa hasn't been hit directly by a hurricane in over a century, other parts of Florida's Gulf Coast are recovering from such storms in the past two years. The Fort Myers area in southwest Florida is still rebuilding from Hurricane Ian, which caused $112 billion US in damage in 2022. Three hurricanes have thrashed Florida's Big Bend region in just 13 months, including Helene.

WATCH | Helene cleanup continues: 

Florida braces for another storm as it cleans up from Hurricane Helene

As the cleanup continues from Hurricane Helene, Florida braces for another storm expected to make landfall later this week.

Milton is a bit atypical since it formed so far west and is expected to cross the entire southern Gulf, according to Daniel Brown, a hurricane specialist at the centre.

"It's not uncommon to get a hurricane threat in October along the west coast of Florida, but forming all the way in the southwest Gulf and then striking Florida is a little bit more unusual," Brown said. Most storms that form in October and hit Florida come from the Caribbean, not the southwestern Gulf, he said.