Tropical Storm Isaac is taking aim on the northern Gulf Coast. The National Hurricane Center is calling Isaac a significant storm and says surge and freshwater flood threat is expected. The 10 p.m. forecast from the Hurricane Center predicted that Isaac would arrive on the coast as a Category 1 storm, with maximum winds at 90 mph.
Isaac is a large tropical cyclone. A dangerous storm surge, heavy rainfall and strong winds extend well away from the center and are expected to affect a large portion of the northern Gulf Coast. The threat of heavy rainfall and flooding is also expected to spread inland over the lower Mississippi Valley region during the next few days.
The storm continues to have trouble organizing. Despite some strong bands of convection that may indicate the formation of an eyewall, dry air in the northeast quadrant of the storm appears to be limiting faster development of the storm. Winds and pressure have not increased significantly over the past several hours.
At 10 p.m., the center of Tropical Storm Isaac was near latitude 27.1 north, longitude 87.0 west. Isaac is moving toward the northwest near 10 mph. This general motion with some decrease in forward speed is expected during the next day or two.
On the forecast track, the center of Isaac will move over the central Gulf of Mexico tonight and approach the coast of southeastern Louisiana and Mississippi on Tuesday afternoon or Tuesday night.
Maximum sustained winds are near 70 mph, with higher gusts. Strengthening is forecast, and Isaac is expected to become a hurricane tonight or early Tuesday, and continue to strengthen until landfall occurs along the northern Gulf Coast.
Tropical storm-force winds extend outward up to 205 miles from the center. The latest minimum central pressure was 979 mb, 28.91 inches.