The remnants of Ian are charging up the East Coast on Saturday after making landfall as a Category 1 hurricane in South Carolina on Friday afternoon.
The monster storm made its first U.S. landfall on Wednesday on Florida's west coast as a powerful Category 4 hurricane, shredding homes with ferocious winds topping 150 mph. Florida's death toll has climbed to at least 81, according to information from local officials.
Ian strengthens once again, forecast to become hurricane on Monday
Tropical Storm Ian has strengthened with maximum sustained winds at 60 mph and is expected to get stronger throughout the night as atmospheric conditions become more favorable for the storm.
Ian is forecast to become a hurricane on Monday, becoming even more intense likely into Tuesday.
Tropical Storm Ian is seen near the coast of Cuba in this satellite image taken September 25, 2022.
National Oceanic and Atmospheric Administration (NOAA) via Reuters
Ian is moving to the northwest to the Northwest at 12 mph, with the center located 160 miles away from Grand Cayman.
Jamaica and the Cayman Islands are expected to experience heavy rain, a heavy surge and possible flash flooding over the next 24 hours.
-ABC News' Dan Peck
Sep 25, 2022, 5:45 PM EDT
Ian weakens slightly but will regain strength overnight
Tropical Storm Ian has weakened slightly, but it is expected to not only strengthen but rapidly intensify overnight as it travels over warm waters in the Caribbean.
As of 5 p.m. ET, the storm system had maximum sustained winds of 45 mph and was moving west-northwest at 12 mph, with the center located about 220 miles away from Grand Cayman.
Dry air ahead of the storm has delayed the strengthening trend so far. But the rapid intensification is expected to occur Monday into Tuesday as the system continues across the northwestern Caribbean and closes in on western Cuba.
Tropical Storm Ian is seen near the coast of Cuba in this satellite image taken September 25, 2022.
National Oceanic and Atmospheric Administration (NOAA) via Reuters
Over the next 24 hours, the outer bands will impact Jamaica and the Cayman Islands, bringing rounds of heavy rain, possible flash flooding and storm surge. Later Monday and into Monday night, Ian will be closing in on western Cuba and will likely bring significant wind and storm surge impacts to the region.
A hurricane warning is in effect for Grand Cayman and portions of western Cuba. A tropical storm watch has been issued for portions of western Cuba, as well as the lower Florida Keys, including Key West.
As of 5 p.m., the forecast track was nudged slightly eastward. Overall, the forecast guidance variability and uncertainty will remain high, and the track for where the storm will be from the middle to the end of the week will continue to shift over the next 24 to 48 hours.
-ABC News' Dan Peck
Sep 25, 2022, 2:58 PM EDT
Caribbean Islands to start experiencing effects from Ian by Monday
Caribbean islands such as Jamaica and Grand Cayman will start to experience the effects from the outer bands of Tropical Storm Ian within the next 24 hours, forecasts show. The islands will experience conditions such as heavy rain, possible flash flooding and storm surge.
The storm system will begin to rapidly intensify overnight into Monday before it closes in on western Cuba on Monday night.
As of 2 p.m., the sustained winds in the tropical storm remained at 50 mph as it moved west-northwest at 12 mph, the center about 265 miles away from Grand Cayman.
An ABC News weather graphic released at 11am Sunday morning shows a closer look at Tropical Storm Ian’s forecast path as it nears Florida as it develops into a hurricane, Sept. 25, 2022.
ABC News
Hurricane warnings are in effect for Grand Cayman and western Cuba, while tropical storm warnings and watches are in effect in other portions of both islands.
As a hurricane, Ian is expected to peak at a Category 4 before weakening slightly as it looks to make landfall on the west coast or panhandle of Florida in the coming days.
A "spaghetti model" weather graphic shows the wide range of possibilities for Tropical storm Ian’s track as it develops into a hurricane, ranging from the west coast of Florida to the Gulf Coast of Mississippi in an ABC News graphic released at 11am on Sept. 25, 2022.
ABC News
There is still some uncertainty to the track Ian will take once the system enters the Gulf of Mexico.
The center of the storm and the worst of the impacts could end up heading toward the western coast of Florida's peninsula, including the Tampa area. The other possible scenario has the storm moving more due north and bringing a possible landfall along the Florida peninsula, impacting cities like Panama City and Tallahassee with more direct effects.
The storm will begin to impact the Florida keys and the southern portions of the state by Tuesday night.
-ABC News' Dan Peck
Sep 25, 2022, 2:38 PM EDT
Gulf Coast, Tampa Bay area particularly vulnerable to hurricanes, expert says
Tropical Storm Ian is marching toward the Gulf Coast of the U.S., a region quite vulnerable to hurricanes.
The underwater geology of the Gulf of Mexico is what makes the Gulf Coast particularly unguarded to the massive influx of seawater, said Michael Brennan, acting deputy director of the National Hurricane Center, according to an article on Inside Science.
The symmetry of the Gulf of Mexico, with its shallow, sloping continental shelf, allows the storm surge to be pushed even higher onto land, Brennan told the outlet.
Shoppers walk to join a line stretching beyond the parking lot outside a retail warehouse as people rush to prepare for Tropical Storm Ian, in Kissimmee, Fla., Sept. 25, 2022.
Gregg Newton/AFP via Getty Images
Because the land around the Gulf Coasts is typically flat, that exacerbates the flooding even more and allows the storm surge to travel farther inland, Brennan said.
"Of all of the hazards of hurricanes --- winds, rain, storm surges –-- surges are what can cause the largest loss of life," Brennan told Inside Science.
The Tampa Bay-St. Petersburg area, one of the regions bracing for Ian, is especially vulnerable to storm surge flooding but has avoided a direct hit from a strong hurricane since 1921.
Editor's Note: This post has been updated to reflect proper attribution to Inside Science.