Tropical Storm Ian, which formed late Friday over the central Caribbean Sea, could threaten Florida as a major hurricane early next week after cutting across western Cuba, forecasters said.
The National Hurricane Center said that residents of the Florida peninsula and Florida Keys should prepare hurricane supplies by sunset on Monday. The storm could hit the peninsula as a Category 3 hurricane or higher, it said.
The storm was about 270 miles south-southeast of Jamaica’s capital, Kingston, at 2 p.m. Eastern on Saturday. It was headed west at 16 miles per hour and carried maximum winds of 45 m.p.h., the Hurricane Center said.
Ian was expected to move across the central Caribbean Sea on Saturday, then pass southwest of Jamaica and near or over the Cayman Islands on Sunday before approaching western Cuba on Monday. South Florida and the Florida Keys could see heavy rain as early as Monday, according to the center, and limited flooding was possible.
On Friday, Gov. Ron DeSantis of Florida declared a state of emergency for 24 counties ahead of the storm, including Broward, Miami-Dade and Palm Beach. Under the order, money would be freed up for protective measures and the National Guard would be activated, Mr. DeSantis said.
“This storm has the potential to strengthen into a major hurricane, and we encourage all Floridians to make their preparations,” he said in a statement.
Monroe County Emergency Management, which oversees Key West, said it would not be making any evacuation decisions as of Saturday morning, according to Kristen Livengood, a spokeswoman. County government offices were set to be open on Monday.
“Review your tropical cyclone preparedness plans now and ensure your emergency supply kit is well-stocked,” a post said. “If your plans include several days’ worth of preparedness actions, be sure to begin your actions as soon as possible.”
Crews in Tampa, on Florida’s west coast, began to remove debris and clear drains ahead of the potential storm, to prevent drainage issues and chances of flooding.
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Ian is expected to generate two to four inches of rain in parts of Haiti and the Dominican Republic, four to eight inches in Jamaica and the Cayman Islands, and six to 10 inches in western and central Cuba, the center said.
This rainfall could lead to flash flooding and mudslides in higher terrain areas, particularly in Jamaica and Cuba, forecasters said. Swells are likely to cause life-threatening surf and rip current conditions.
The government of the Cayman Islands upgraded its hurricane watch to a hurricane warning for Grand Cayman. A warning is usually issued 36 hours before the anticipated first occurrence of tropical-storm-force winds.
Jamaica, Little Cayman and Cayman Brac are now under a tropical storm watch, demonstrating expected activity within 48 hours.
Ian is the ninth named storm of the 2022 Atlantic hurricane season. A storm is given a name after it reaches wind speeds of at least 39 m.p.h.
Fiona, which formed on Sept. 15, strengthened into a major hurricane before being downgraded late Friday to a post-tropical cyclone. It made landfall in eastern Canada early Saturday, after days of lashing Bermuda, Puerto Rico and the eastern Dominican Republic.
Tropical Storm Gaston, which formed on Tuesday, was forecast to move near or over the Azores in the North Atlantic on Saturday morning.
And Tropical Storm Hermine formed in the Eastern Atlantic on Friday and was expected to bring heavy rains to the Canary Islands, causing flash flooding in some high-terrain areas, forecasters said.
The Atlantic hurricane season, which runs from June through November, had a relatively quiet start, with only three named storms before Sept. 1 and none during August, the first time that had happened since 1997. Storm activity picked up in early September with Danielle and Earl, which formed within a day of each other.
In early August, scientists at the National Oceanic and Atmospheric Administration issued an updated forecast for the rest of the season, which still called for an above-normal level of activity. In it, they predicted that the season — which runs through Nov. 30 — could see 14 to 20 named storms, with six to 10 turning into hurricanes with sustained winds of at least 74 m.p.h.
Three to five of those could strengthen into what NOAA calls major hurricanes — Category 3 or stronger — with winds of at least 111 m.p.h.
Last year, there were 21 named storms, after a record-breaking 30 in 2020. For the past two years, meteorologists have exhausted the list of names used to identify storms during the Atlantic hurricane season, an occurrence that has happened only one other time, in 2005.
The links between hurricanes and climate change have become clearer with each passing year. Data shows that hurricanes have become stronger worldwide during the past four decades. A warming planet can expect stronger hurricanes over time and a higher incidence of the most powerful storms, though the overall number of storms could drop because factors like stronger wind shear could keep weaker storms from forming.
Hurricanes are also becoming wetter because of increased water vapor in the warmer atmosphere; scientists have suggested storms like Hurricane Harvey in 2017 produced far more rain than they would have without the human effects on climate. Also, rising sea levels are contributing to higher storm surge — the most destructive element of tropical cyclones.