Hurricane Isaac churning to US Gulf coast

Tropical Storm Isaac has now been upgraded to a category one hurricane and US President Barack Obama is warning residents in the path to heed evacuation warnings.

Obama has declared an emergency in Louisiana, allowing federal funds to be released to local authorities.

The storm is predicted to make landfall by tonight.

Isaac is expected to hit New Orleans seven years after the much stronger Hurricane Katrina struck.

Obama has urged all residents of the Gulf Coast to listen to local officials and follow their directions.

Meanwhile, the National Hurricane Centre says Isaac is also threatening heavy rainfall of as much as 20 inches in isolated spots, and could spark possible tornadoes along the northern Gulf Coast.