Tropical Weather Latest: Helene makes landfall as a Category 4 hurricane in northwestern Florida

Fast-moving Hurricane Helene made landfall in the Big Bend area of Florida's northwestern coast as a Category 4 storm Thursday evening, threatening a “catastrophic” storm surge as well as damaging winds, rains and flash floods hundreds of miles inland across much of the southeastern U.S., forecasters said.

Authorities in Georgia reported two people killed in a possible tornado in south Georgia as the storm approached, and Florida Gov. Ron DeSantis said one person died while driving on Interstate 4 when a sign fell onto their car.

The storm knocked out power to over 1 million homes and businesses in Florida as it approached and came ashore.

States of emergency were declared in Florida, Georgia, the Carolinas, Virginia and Alabama.

In the Pacific, former Hurricane John strengthened Thursday morning back into a hurricane as it threatened areas of Mexico’s western coast with flash flooding and mudslides. It was then downgraded to a tropical storm as it crept along the coast of the Mexican state of Michoacan..

Meanwhile, Tropical Storm Isaac formed Wednesday in the Atlantic Ocean and was expected to strengthen as it moves east away from the U.S., possibly becoming a hurricane by the end of the week, forecasters said.

Follow AP’s coverage of tropical weather at https://apnews.com/hub/hurricanes.

Here's the latest:

1 person dies in Florida while driving on Interstate 4, governor says

Florida Gov. Ron DeSantis said there was a report of one person dying when a sign fell onto their car as they were driving on Interstate 4 in Tampa.

“It just shows you that it’s very dangerous conditions out there. You need to be, right now, just hunkering down,” he said at a news conference late Thursday.

DeSantis said more fatalities were possible as the storm advances and that 3,500 National Guardsmen were standing by to help respond.

“When Floridians wake up tomorrow morning, we’re going to be waking up to a state where, very likely, there’s been additional loss of life. And certainly, there’s going to be loss of property,” he said. “You’re going to have people that are going to lose their homes because of this storm. So please keep those folks in mind, keep them in your prayers.”

Helene makes landfall in northwestern Florida

Hurricane Helene made landfall Thursday in northwestern Florida as a Category 4 storm as forecasters warned of “catastrophic” flooding along the Gulf Coast.

The National Hurricane Center in Miami said Helene roared ashore around 11:10 p.m. EDT near the Perry, Florida, in the Big Bend area of the state's Gulf Coast. It had maximum sustained winds of 140 mph (225 kph).

Officials have forecast storm surges of up to 20 feet (6 meters) and warned they could be particularly “catastrophic and unsurvivable” in Florida’s Apalachee Bay.

Hurricane warnings and flash flood warnings extended far beyond the coast up into northern Georgia and western North Carolina.

Power outages continue to rise in Florida

As of 11 p.m. EDT, more than 885,000 customers in Florida were without power, according to tracking site poweroutage.us.

The site’s map showed multiple counties in Florida’s Big Bend area — where Helene is expected to make landfall — where a majority of customers did not have power.

John is no longer a hurricane. The tropical storm is moving slowly along Mexico’s coast

John was downgraded to a tropical storm Thursday evening as the slow-moving storm crept along the coast of the Mexican state of Michoacan, the U.S. National Hurricane Center said.

The former hurricane was sustaining wind speeds of 70 mph (110 kph) and still threatened coastal areas with severe flash flooding, the center said.

John initially hit Mexico late Monday when it made landfall as a Category 3 hurricane in Acapulco on the country’s southern Pacific coast. It blew tin roofs off houses, triggered mudslides and toppled scores of trees. After weakening inland, it reemerged over the ocean, reforming as a tropical storm Wednesday and strengthening back into a hurricane Thursday.

The hurricane center said the storm is expected to weaken Thursday night and into Friday.

2 killed in Georgia in possible tornado as storms from Hurricane Helene hit

Two people have died after a possible tornado struck a mobile home in south Georgia on Thursday night, Wheeler County Sheriff Randy Rigdon told WMAZ-TV.

The damage was reported as heavy thunderstorms from Hurricane Helene raked much of the state. Wheeler County is about 70 miles (113 kilometers) southeast of Macon.

Tropical Storm Isaac will likely become a hurricane soon, forecasters say

Tropical Storm Isaac in the mid-Atlantic Ocean strengthened Thursday night and was expected to become a hurricane soon, the U.S. National Hurricane Center said.

The storm was moving east away from the U.S. at 12 mph (19 kph) and was 910 miles (1,470 kilometers) northeast of Bermuda. Its maximum wind speeds were 65 mph (100 kph).

There were no coastal watches or warnings associated with the storm, but the hurricane center said Bermuda was experiencing swells that could lead to life-threatening rip currents.

Helene’s turbulent eyewall begins to move ashore

Hurricane Helene’s eyewall has begun moving ashore in the Big Bend area of Florida’s northwestern coast, the U.S. National Hurricane Center said.

The Category 4 storm is expected to produce “catastrophic winds” in the area over the next few hours, the center said.

“This is an extremely dangerous and life-threatening situation,” the hurricane center said. “Persons should not leave their shelters and remain in place through the passage of these life-threatening conditions.”

The center warned when the storm’s eye comes ashore, conditions will temporarily calm, but the eye’s other side will quickly arrive and produce hazardous winds again.

As of 10 p.m., the storm was 65 miles (105 kilometers) south of Tallahassee, Florida, with sustained winds of 140 mph (225 kph).

Power outages rapidly increase along Florida’s west coast

More than 500,000 homes and businesses had lost power in Florida as of 8:30 p.m., and that number is rising quickly, according to tracking site poweroutage.us.

Most outages were along the state's west coast, where Hurricane Helene was approaching. Duke Energy, a major energy provider serving west-central Florida and the Panhandle, and Florida Power & Light Company, the state's largest energy provider, were reporting over 150,000 outages each.

Tornado watch issued for much of Florida and southeastern Georgia

A tornado watch was issued late Thursday for much of Florida and southeastern Georgia, the National Weather Service in Tallahassee said.

Florida’s Gulf Coast, including Tampa and the Big Bend area, where Helene is expected to make landfall, were under the watch, as was the state’s Atlantic coast, including Orlando. The tornado watch will be in effect through early Friday morning.

Florida sees mass power outages ahead of Helene’s landfall

More than 340,000 homes and businesses were without power in Florida shortly as of 7:30 p.m. local time, according to tracking site poweroutage.us.

Among them were 120,000 customers of Duke Energy, a major energy provider serving west-central Florida and the Panhandle. The utility’s outage map showed most of its affected customers — some 105,000 — were concentrated in the Tampa area on the state’s Gulf Coast.

While Tampa is south of where Helene is expected to make landfall, the area was still under a storm surge warning and a tropical storm warning, with forecasters expecting dangerous surges of up to 15 feet (4.5 meters) and winds topping 40 mph (64 kph).