Helene is now here, and is in the process of gathering strength as it gets ready to traverse the Gulf of Mexico waters on its way to a Florida landfall on Thursday.
Hurricane and tropical storm warnings have been issued for parts of Florida and Mexico, as well as a storm surge warning for Tampa Bay. Hurricane watches remain place for parts of Cuba. Residences should prepare quickly for impacts and heed evacuation orders.
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According the latest forecast from the U.S. National Hurricane Center (NHC), Helene is expected to become a hurricane on Wednesday morning. The storm is then forecast to rapidly strengthen over the eastern Gulf of Mexico and become a major hurricane on Thursday.
“On the forecast track, the centre of Helene will pass near the northeastern coast of the Yucatan Peninsula on Wednesday, move across the eastern Gulf of Mexico on Wednesday and Thursday, and reach the Big Bend coast of Florida late Thursday,” NHC said in Tuesday evening’s update.
If it becomes a major hurricane as projected, that means it will have undergone just 48 hours of rapid intensification over the extremely warm waters of the Gulf of Mexico.
A spectacularly perfect track will curve the storm in between Mexico and Cuba. That will allow the storm to continue growing its eye, without disruption to land. The track also takes the storm over the loop current, which funnels in very warm water northward into the Gulf of Mexico where the warmest waters are.
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Landfall is expected along the Florida Panhandle, anywhere from Tampa to Tallahassee, Fla. Time is now running out for residents to make appropriate impact plans, which could include flooding rains, and potentially life-threatening storm surge. Power outages will likely be counted in the millions of customers.
There will be higher residential impacts if the track shifts east towards Tampa. Current trajectory to Florida’s Big Bend region is in a much lower population, so there should be a lower cost of damages depending on its track.
A state of emergency has been declared for 41 Florida counties, including Lee, Collier, and Charlotte counties, as the state braces for the potential impacts of Helene.
Regions of southeastern Florida are being urged to prepare as Helene’s impacts will be exceptionally large and widespread. Significant power outages, and the threat of tornadoes will stretch far across the region.
“We already have nearly 18,000 linemen staged (and more en route), and are ready with search and rescue and roadway clearing crews,” shared Florida Gov. Ron DeSantis on X on Tuesday. “Stay tuned to local and state emergency recommendations and alerts. Get preparations in place now for the storm and heed evacuation directives, if issued, from local officials.”
Residents of Florida’s coastal areas will likely face evacuations.
(The Weather Network’s Mark Robinson will be live on location in Florida as Helene makes landfall)
Total rain accumulations of 100 to 200 mm are forecast over western Cuba and the Cayman Islands, with isolated totals possibly reaching 300 mm. Over the eastern Yucatan Peninsula, 100 to 150 mm rain is expected with isolated totals over 200 mm.
Over the southeastern U.S., the storm is expected to produce total rain accumulations of 100 to 200 mm of rainfall, isolated totals of 300 mm, bringing a risk of flooding, of which some could be considerable.
“This rainfall will likely result in areas of considerable flash and urban flooding, with areas of significant river flooding likely, including the risk of landslides in areas of steep terrain in the southern Appalachians,” the NHC warns.
Dangerous storm surge, and strong winds are also expected for portions of the northeastern Gulf Coast, including the Florida Panhandle and sections of Florida’s west coast.
“The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline,” says the NHC.
In places like Tampa Bay, storm surge could reach between 1.5-2.5 metres, while Florida’s Ochlockonee River could see storm surge as high as 3-4.5 metres. Some isolated areas could even see storm surge up to five metres high.
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Special attention needs to be paid to the storm surge in the Tampa Bay metro area, where the latest surge forecast highlights up to 2.5 metres for peak surge, which will cause significant damage if comes to fruition.
All models highlight Hurricane Helene will be well above average in terms of storm diameter, extending to more than 800 kilometres across. It’ll take up roughly half the size of the Gulf of Mexico, with impacts spreading in some cases to as much as 500 kilometres from the eye.
The largest hurricane diameter in history was Typhoon Tip in 1979, having a span exceeding 2,000 kilometres. Helene is forecast to be about 60 per cent larger than Hurricane Idalia, which caused $3.6 billion worth of damage. Even though Helene is forecast to have a diameter close to 800 kilometres, it’s half of what Hurricane Sandy’s width was in October 2012.
The peak of hurricane season occurred on Sept. 10, but we’re in the thick of the season through the middle of October, a period during which some of history’s most intense hurricanes have thrived and roared ashore.
It’s been an unusually and surprisingly quiet hurricane season across the Atlantic Ocean so far this year. Extremely warm sea surface temperatures and a budding La Niña led forecasters to expect a hyperactive season—the opposite has happened so far, with relatively few storms developing over the steamy ocean so far this year.
Despite the unexpected lull in activity this season, we could still see dangerous storms develop over the coming days and weeks. Coastal residents should closely monitor forecasts and have emergency preparedness kits ready to go long before a storm ever threatens land.
