Tropical Storm Isaac Almost Certain to Become Hurricane

Nearby mayors have not ordered evacuations

Tropical storm Isaac is on the verge of becoming a hurricane and remains headed for a direct hit on New Orleans on Tuesday night.

The city and surrounding areas are bracing for impact, with Isaac expected to reach land overnight and threaten a wide region of the Gulf coast.

The National Hurricane Center warned that Isaac has the potential to cause flooding in Louisiana, Alabama, Mississippi and Florida through rising water levels of up to 12ft from storm surges and heavy, prolonged rainfall of up to 20in. Winds are expected to be far in excess of 70mph and there will be the threat of tornadoes.