Forecasters upgraded Helene to a tropical storm with expected growth to a strong hurricane in the second half of this week.

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Forecasters upgraded Helene to a tropical storm with expected growth to a strong hurricane in the second half of this week.

Tropical storm and hurricane watches were issued for parts of the lower Florida Keys, western Cuba and Mexico’s Yucatán peninsula Tuesday morning as forecasters elevated Potential Tropical Cyclone Nine to Tropical Storm Helene.

Helene formed in the northwestern Caribbean Sea, just south of the western tip of Cuba and is expected to reach hurricane strength, with wind strengths of 115 mph, by Wednesday. It’s trajectory as of midday Tuesday threatens the Florida panhandle, which forecasters say could be hit on Thursday.

Meteorologists say this system will be particularly big -- with a wide wind field. They expect the storm to move fast, meaning a huge inland swathe will endure the brunt of the storm and its predicted storm surge — or abnormal rise of water.

Florida Gov. Ron DeSantis announced the state is preparing for Helene, with thousands of linemen, search and rescue, and roadway clearing crews on the way.

This hurricane season, which stretches from June through November, has been abnormally quiet with the last such storm happening on August 12.

Matthew Rosencrans, the lead hurricane forecaster for the National Weather Service, told NPR earlier this month that the water in the Atlantic is warmer than usual, which helps storms develop into powerful forces. Rosencrans and other forecasters expect more storms could form in the coming weeks.