Tropical Storm Isaac 11 a.m. update: Isaac intensifying as it moves towards Louisiana

NEW ORLEANS - Isaac remains just under hurricane strength as it intensifies in a northwestward direction over the Gulf of Mexico.

A hurricane warning is in effect for the northern Gulf coast including New Orleans. Isaac is a significant storm surge and freshwater flood threat to the northern Gulf coast.

At 11 a.m., Isaac was moving toward the northwest near 10 mph. A northwestward motion at a slightly slower speed is expected over the next day or two.

The center of Isaac should reach the coastline of southeastern Louisiana as early as this evening.

Maximum sustained winds are near 70 mph with higher gusts. Isaac is expected to become a hurricane before landfall and slowly weaken after that.

Tropical storm force winds extend outward up to 185 miles from the center.