Tropical Storm Helene predicted to form today, strengthen into potential Category 3 by landfall

Tropical Storm Helene could form later today and it is forecast to strengthen into a major hurricane before it strikes Florida or the northern Gulf Coast later this week.

Interests along the U.S. Gulf Coast from Louisiana to Florida should monitor this situation closely, stay updated on how the forecast unfolds in the days ahead and have their hurricane plans ready to go.

If Tropical Storm Helene does strengthen into a hurricane, it will be the second hurricane to hit the southeast this month.

Watches and warnings issued:

Tropical alerts have been issued for portions of the Yucatan Peninsula, the Greater Antilles, and Florida.

T​his means tropical storm conditions are expected and hurricane conditions are possible in these areas within the next 36-48 hours.

Where it is right now: The storm is located about 120 miles west of Grand Cayman, with winds of 35 mph. Thunderstorms are gradually becoming more organized in this area, and strengthening is expected today.

The storm was dubbed Potential Tropical Cyclone Nine, a procedure NHC uses to issue watches and warnings ahead a tropical depression or storm forming, on Monday morning.

Here is the timeline:

-​ Tuesday: The storm is expected to near Cancún, Cozumel and western Cuba becoming a named storm, Helene, at either tropical storm or even Category 1 hurricane intensity. Locally heavy rain, strong wind gusts and storm surge flooding are possible in those areas. Parts of western Cuba could pick up 12 inches of rain or more.

-​ Wednesday: Helene could have some lingering impacts in Cancún, Cozumel and western Cuba, especially early. We then expect Helene to enter the southern Gulf of Mexico as a hurricane. Some high surf and outer rainbands could reach parts of Florida’s Gulf Coast from the Keys to the Panhandle.

-​ Thursday: Despite some remaining uncertainty in the forecast, Helene is forecast to make landfall as a major hurricane Thursday afternoon or evening. While computer forecast models suggest the most likely location for a landfall is somewhere from Florida’s Big Bend to the Panhandle, remember that hurricane impacts (surge, winds, rain) often happen far from the center.​ There are still a few computer ensemble model forecasts with tracks as far east as Florida’s West Coast and as far west as southeast Louisiana or Mississippi. So, everyone along the northern Gulf Coast from Louisiana to Florida should continue to monitor this forecast for any possible changes ahead.

-​ Friday: This system is most likely to push inland quickly with some lingering strong wind gusts and locally flooding rain over parts of the Southeast.

How strong could it become:

Helene is forecasted to reach major hurricane intensity in the Gulf ahead of landfall.

That’s because heat content is one favorable ingredient for intensification, and the map below shows there is plenty of deep, warm water in the northwest Caribbean Sea and parts of the Gulf of Mexico. In fact, Gulf of Mexico heat content is at record high levels for this time of year, according to University of Miami tropical scientist Brian McNoldy.

B​ut it’s not just warm water.

Forecast models suggest upper level winds could spread apart over Helene, which is favorable for strengthening, instead of shearing and tilting Helene’s circulation.

F​or those reasons, Helene could reach at least Category 3 intensity in the eastern Gulf of Mexico before landfall.