Isaac May Become Major Hurricane in Gulf

Tropical Storm Isaac could intensify into a major hurricane with winds exceeding 110 mph (177 kph) and threaten the U.S. Gulf Coast from Louisiana to Florida by the middle of next week — the seventh anniversary of devastating Hurricane Katrina.

Hurricane Isaac. Image courtesy NASA.

Meteorologists think Tampa, Florida — where the Republican National Convention will begin Monday — is less likely to feel the brunt of Isaac. The storm is more likely to take a more westerly path away from the Florida peninsula after it moves from the Caribbean Sea into the Gulf of Mexico, said Keith Blackwell, meteorologist at the University of South Alabama’s Coastal Weather Research Center in Mobile.

As of 5 p.m. today, the center of Tropical Storm Isaac was in the northeastern Caribbean Sea. It was moving west-northwest at about 16 mph (about 26 kph). Its strongest winds were about 40 mph (about 64 kph).

A tropical storm becomes a hurricane when its strongest winds reach 74 mph (about 119 kph). If its winds reach at least 111 mph (about 178 kph) it becomes a major hurricane.

When Isaac moves into the open water of the Gulf, it is likely to encounter conditions that are favorable for intensification, Blackwell said.

“Anywhere from Louisiana to northwest Florida could be at significant risk from this thing,” Blackwell said.

Hurricanes draw their strength from ocean water that has been heated to at least 80 degrees Fahrenheit (about 27 degrees Centigrade). The water temperature in much of the gulf is 86 degrees Fahrenheit (about 30 degrees Centigrade), making the water capable of fueling a major hurricane.

“The water temperature is as warm as a bathtub,” Blackwell said.

Should Isaac intensify into a major hurricane, it will be roaming the Gulf on the same date — August 29 — that Hurricane Katrina struck New Orleans in 2005.

Katrina became one of the most devastating storms in U.S. history, killing more than 1,800 people and causing about U.S. $81 billion in damage.

Still, Blackwell said it’s too early to know for certain whether Isaac will reach Category 3 status, which would make it a major hurricane.

Isaac’s path is likely to take it near the Florida Keys, where officials are pondering whether to order tourists to evacuate in advance of the storm. Isaac is expected to make its closest approach to the Keys late Sunday or early Monday.

But Isaac is not expected to be a major storm as it moves past the Keys. Andy Newman, media relations supervisor for the Monroe County Tourist Development Council, said it’s “highly unlikely” that emergency management officials will order residents to evacuate the low-lying islands that stretch for about 150 miles (240 kilometers) south of the Florida Peninsula.

But the Keys have thousands of tourists visiting every day, and officials might decide to order them to evacuate, Newman said.

Willie Drye has been writing about hurricanes and other topics for National Geographic News since 2003. Follow his blog, Drye Goods.

Changing Planet

Meet the Author
Willie Drye is an award-winning author and a contributing editor for National Geographic News. He and his wife live in Wilmington, North Carolina.