Storm Isaac 'on the Verge' of becoming Hurricane

Tropical Storm Isaac is "on the verge" of becoming a hurricane as it barrels towards New Orleans, forecasters said Tuesday, nearly seven years after Hurricane Katrina devastated the city.

"Isaac (is) on the verge of becoming a hurricane," the National Hurricane Center said in its 09:00 GMT advisory, adding that there was a "significant storm surge and freshwater flood threat to the northern Gulf coast."

The Miami-based NHC predicted the center of the storm would be over the Louisiana coast by late Tuesday or early Wednesday, saying "preparations to protect life and property should be rushed to completion."

Forecasters warned of a coastal storm surge of up to 3.6 meters in southeast Louisiana and Mississippi.

The storm is set to hit on the exact anniversary of Hurricane Katrina, which plowed into New Orleans on August 29, 2005, triggering one of the worst natural disasters in U.S. history, which killed some 1,800 people.

Isaac has already cast a pall over the U.S. Republican convention in Florida, which was forced to delay main events for one day and risks losing prime time media attention to the approaching storm.

As of 09:00 GMT, the storm was 205 kilometers southeast of the mouth of the Mississippi river, moving to the northwest at 12 miles per hour, according to the NHC.

The storm was packing gusts of wind of up to 70 miles per hour, just short of the 74 mph cut-off for a Category One hurricane on the Saffir-Simpson wind scale.