Tropical Storm Ian is expected to become a hurricane later today when its “significant strengthening” begins, but the National Hurricane Center is much less confident where along Florida’s Gulf coast the storm could make landfall, saying there is “significant uncertainty” with the longer range forecast. Florida Gov. Ron DeSantis said the storm will have “broad impacts throughout the state.”

In its 2 p .m. Sunday update, the National Hurricane Center said Tropical Storm Ian was still with maximum-sustained winds of 50 mph. The storm was located about 265 miles south-southeast of Grand Cayman and 540 miles southeast of the western top of Cuba, and it was moving to the west-northwest at 24 mph. Tropical-storm force winds extend 60 miles from Ian’s center.

A hurricane warning is in effect for Grand Cayman and for parts of Cuba.

The hurricane center said it has “relatively high confidence” in its short-term forecast that calls for Ian to make a gradual turn to the northwest later Sunday as it passes southwest of Jamaica, then moves west of the Cayman Islands on Monday and near or over western Cuba by early Tuesday.

“Ian is expected to become a hurricane by tonight or early Tuesday, and is forecast to reach major hurricane strength before it reaches western Cuba,” the NHC.

The storm is expected to have 120 mph winds in 36 hours and 130 mph winds in 60 hours.

It’s the forecast for Ian three to five days from now that’s problematic. Computer forecast models agree Ian will hit Florida but don’t agree on where. “There are still significant differences regarding the exact track of the storm, especially after 72 hours,” the NHC cautioned.

Two models, the UKMET and ECMWF, show the storm tracking east and making landfall in west-central Florida. Two other models, the GFS and HWRF, show the storm moving more west and take Ian into the central or western Florida panhandle. Earlier Sunday there was between 220-250 miles difference between the model tracks in the forecast for Day 4 and Day 5 for Ian, the NHC said.

The hurricane center’s current forecast track for the storm basically splits the difference between the different model sets with the NHC’s best guess.

“However, there is…