The storm is located about 265 miles (425 km) west of Fort Myers, Florida, packing maximum sustained winds of 40 miles per hour (65 km/h).

"Although the storm has strengthened slightly, we still expect Arlene to weaken soon due to increasing wind shear and dry air," the Miami-based weather forecaster said.

(Reporting by Ashitha Shivaprasad in Bengaluru; Editing by Chris Reese and Diane Craft)