A tropical storm advisory has been issued for parts of four southern U.S. states as tropical Tropical Storm Debby, the fourth storm of the 2012 Atlantic hurricane season, makes its way to the Gulf Coast bringing heavy rains and thunderstorms.

The U.S. National Hurricane Center on Sunday afternoon said the storm had maximum sustained winds of 95 kilometers per hour, and was expected to move northeast over the Gulf of Mexico over the next few days.

The storm is expected to make landfall on some of the low-lying coastal areas in Louisiana, prompting Governor Bobby Jindal to declare a state of emergency.

Tropical storm warnings also were issued for the Mississippi-Alabama border and parts of Florida.

Debby has forced the suspension of 8 percent of the region's oil and gas production.

Officials said nine production platforms and one drilling rig were evacuated. The reduced production is not expected to impact oil prices unless the storm strengthens and forces more production platforms to close.

This is the first time that four tropical storms have formed before July 1 during the Atlantic hurricane season, since record keeping began in 1851.