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Will Hurricane Helene emerge like a monster from the Gulf?

2024-12-19 11:59:34 Stocks

The tropical system in the western Caribbean may not look like much yet, but don’t be fooled. History has shown the Gulf of Mexico can be a pressure cooker, turning systems like this one from wimpy windstorms to devastating monster storms almost overnight under the right conditions.

In this case, the hot stove is already on, with warmer than normal water across the Gulf expected to help boost the storm’s winds as much as 75 mph by Thursday morning.

That means the brewing system is likely to become Hurricane Helene on Wednesday, then see an increase in winds that makes it a Category Three hurricane with 115 mph or more as it approaches Florida’s Big Bend on Thursday, according to the National Hurricane Center Forecast.

Tuesday updates:Hurricane watch for Florida Gulf Coast

The storm is forecast to strengthen with potential explosive force in the Gulf. It’s called rapid intensification and it’s happened before. In fact, most of the worst hurricanes in history have experienced rapid intensification, Ken Graham, the National Weather Service director, has said in interviews with USA TODAY.

That includes two recent hurricanes in the Gulf of Mexico: Hurricane Michael, which struck near Mexico Beach in the Florida Panhandle in 2018, and Hurricane Ian, which hit Florida’s southwest coast in 2022.

The fierce official forecast for the Gulf storm is still below the increase some computer models predict. Hurricane experts say the higher-end forecasts for peak winds and low barometric pressure could materialize if the storm develops a classic tropical cyclone structure before it moves into the southern Gulf of Mexico.

Even though forecasting a rapid transition in storms has improved, accurately forecasting such radical events is still considered “the wild, wild west,” said David Roth, a meteorologist with the Weather Prediction Center.

What is rapid intensification?

A period during which wind speeds in a storm rapidly accelerate. The technical definition is an increase of least 35 mph in a 24-hour period, but storms can intensify more than that or continue to intensify over a longer period under the right conditions.

Rapid intensification typically occurs when a storm moves into or over warm water. Plentiful moisture and warmer water provide energy that helps hurricanes build the high cloud pillars that give them additional strength.  

Water temperature in the Gulf is at a record high for this time of year, according to Brian McNoldy, a senior research scientist at the University of Miami’s Rosenstiel School.

Wind shear is expected to be lower as the storm moves into the Gulf of Mexico, which reduces the risk that high cloud tops could be torn apart by opposing winds.

In June, Beryl took advantage of warm waters in the eastern Caribbean, becoming a Category 4 hurricane with winds of 130 mph. It had gained 95 mph in wind speeds in just 42.5 hours, beating out all but a few previous hurricanes.

Why is rapid intensification so dangerous?

Higher wind speeds that develop during rapid intensification have a two-fold impact on storms and make it more difficult to plan and enforce evacuations. During previous storms people in harm's way have gone to bed in the evening expecting a lower end hurricane and woke up in the morning to find themselves facing something else entirely.

Hurricane Otis in the eastern Pacific last summer saw its winds increase 110 mph in 24 hours, shocking the residents of Acapulco, Mexico.

The higher winds and lower pressure are more destructive on their own, but higher winds also push more water forward in storm surge, particularly in the Gulf of Mexico, where the continental shelf tends to increase the height of surging seawater as a storm makes landfall.

The west coast of Florida, including Tampa Bay, is particularly vulnerable to storm surge, Jamie Rohme, the hurricane center’s deputy director said Monday.

Which hurricanes have rapidly intensified?

Of the 10 hurricanes with 150 mph winds or greater that made landfall in the contiguous United States in just over 100 years, all but one of them exploded in force and power during rapid intensification.

Hurricane Ian in 2022 had two such bursts of rapidly intensifying winds, briefly reaching 155 mph before making landfall at Cayo Costa in Southwest Florida on Sept. 28, 2022.

Hurricane Andrew, the storm that devastated parts of Southwestern Miami Dade county in Florida in 1992 also rapidly intensified. Andrew increased from a minimal hurricane to 175 mph winds in just 36 hours, and its central pressure dropped 72 millibars, as it closed in on the Bahamas. Its winds were still 165 mph when it made landfall in Miami on Aug. 24.

In 2021, Hurricane Ida exploded in intensity as it approached the Louisiana coast. Its wind speeds increased from 85 mph to 150 mph in 20 hours, making it one of the fifth-strongest hurricanes to strike the U.S. mainland.

Are forecasters improving at forecasting rapid intensification?

Improvements in data collection through the work of hurricane hunters and developing technologies, such as the dropsondes and drones deployed by the aircraft, have provided more information to the computer models used in forecasting.

A decade ago, the National Hurricane Center wasn’t forecasting rapid intensification, but significant progress has occurred since then.

“We were pretty successful in Idalia,” the Center Director Michael Brennan told USA TODAY earlier this year.

However, like Roth, Brennan and others say forecasting rapid intensification is still challenging. Both Beryl and Otis surprised meteorologists with the degree to which they intensified.

Is climate change playing a role?

Many scientists say yes.

Tom Knutson, a senior scientist with NOAA’s Geophysical Fluid Dynamics Laboratory, has previously stated that although scientists remain unsure about the long-term overall impacts of warmer temperatures on tropical cyclones, rapid intensification is expected to increase in a warmer climate.

Some scientists say climate change already is reflected in the rapid intensification seen in recent hurricanes.

A new study published by Princeton University researchers in February concluded rapid intensification events are “already more hazardous than normal cyclones and future climate warming causes large increases in the likelihood of (rapid intensification) close to land.”

(This story was updated to correct a misspelling/typo.)

Dinah Voyles Pulver covers climate change and the environment for USA TODAY. She's been writing about hurricanes, tornadoes and violent weather for more than 30 years. Reach her at [email protected] or @dinahvp.

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