Four named storms in early July set record

Quiet hurricane seasons coincide with El Nino conditions in the Pacific. When Pacific water temperatures rise, it changes global wind patterns. High in the atmosphere, wind shear knocks down storms that arise in the Atlantic, preventing many from reaching wind speeds of at least 74 mph.

But in stormy years like 2005, Atlantic sea surface temperatures are warming above 81 degrees. Without much wind shear, humid westerly winds from Africa’s bulge grow stronger. The warmer ocean heats the air in a rising column, creating a center of moist low pressure.

Trade winds rush in toward this depression. Combined with the planet’s rotation, they spin clouds counterclockwise around this steamy core, or “eye” of the storm.

Gulf conditions
Conditions in the Gulf of Mexico can perpetuate these storms over days and hundreds of miles.

Normally, the Gulf consists of a thin layer of warm water that rides atop a foundation of cold seawater. When storms cross into the basin, the winds churn these layers and the colder water pulls the plug on the storm’s motor.

But sometimes, the large Loop Current spawns deep pockets of warm water called eddies that move east-to-west and cover up to 20 percent across the Gulf. If a hurricane happens to pass over one of these eddies, it acts like a shot of espresso and re-caffeinates the storm.

Louisiana state climatologist Barry Keim says surface temperatures in the Gulf are at least 81 degrees, adding to the dangerous conditions.

“This is going to be a big, bad storm,” Keim said of Hurricane Dennis. “The fuel for the storm is the energy of the evaporation off the Gulf surface. Warmer water means more fuel to feed the system.”

Could last 20 years or more
Experts believe the current hurricane surge is part of an obvious storm cycle.

Roughly from 1970-94, Atlantic hurricane activity in the United States was relatively mild.

But 1995-2004 is the most active 10 consecutive hurricane seasons on record, Gray says. The cycle of heightened activity could last another 20 years or more.

The trend is believed to be a consequence of natural salinity and temperature changes in the Atlantic’s deep current circulation that shift back and forth every 40-60 years.

Keim says the last year there were this many named storms early in the storm season was 1959, with the fourth named on July 7, 1959. In 1900, there were four storms by mid-July, but only one made landfall, Willoughby said.

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