Tropical Storm Helene is expected to form in the western Caribbean Sea and could intensify into a strong 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.
Where it is right now: A broad area of low pressure is in the western Caribbean Sea. Thunderstorms are gradually becoming more organized in this area.
It's been dubbed Invest 97L, a convention used by the National Hurricane Center to identify features they are monitoring for future development.
The NHC also scheduled its first Hurricane Hunter mission to the western Caribbean Sea for this afternoon.
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Here is when a storm could form and where it could track:
- Monday-Tuesday: The latest computer forecast models suggest a tropical depression or storm could form as soon as late Monday or Tuesday. By late Tuesday, Helene could near Cancún, Cozumel and western Cuba as either a tropical storm or even a Category 1 hurricane. Locally heavy rain and strong wind gusts are possible in those areas.
- 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, most likely as a hurricane. Some high surf and outer rainbands could reach parts of Florida's Gulf Coast from the Keys to the Panhandle.
- Friday: This system is most likely to continue inland with weakening winds, but locally flooding rain over parts of the Southeast.
How strong could it become: Helene could become a formidably strong hurricane in the Gulf.
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 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.
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But it's not just warm water.
Some forecast models suggest upper level winds could spread apart over Helene, which is favorable for strengthening, instead of shearing and tilting Helene's circulation.
For those reasons, Helene could reach Category 3 intensity in the eastern Gulf of Mexico before landfall.
Rainfall potential: While it's too soon for specifics on other impacts - including storm surge and winds - we expect Helene to produce heavy rainfall generally along and to the east of its track.
The heaviest rain is expected Thursday into Friday in parts of the Southeast, but some bands of heavy rain could arrive as early as Wednesday. This rain could lead to flash flooding, especially where it combines with storm surge and over higher terrain.