National Hurricane Center (Updated Maps): Isaac Nearly a Hurricane, Brings Coastal Flood Threat

Tropical Storm Isaac is on the verge of becoming a hurricane, the National Hurricane Center advised in its Tuesday morning warning.  Isaac is expected to reach hurricane status by the end of the day.

The storm has reached maximum sustained winds of 70 mph and is about 105 miles south-southeast of the mouth of the Mississippi River, the advisory said. Maximum sustained winds of 74 mph are needed to reach hurricane status.

The Miami-based center updated its hurricane warning for east of Morgan City, La. to the Alabama-Florida border, including New Orleans, Lake Pontchartrain and Lake Maurepas. A hurricane watch is also in effect for Intracoastal City to Morgan City, La.

Isaac is moving towards the northwest at about 7 mph, the center said. Reuters reports that this slow forward speed can bring higher rainfall totals. The Hurricane Center added that Isaac is expected to continue on its path with its center possibly reaching the Louisiana coast by Tuesday night or early Wednesday.

With expected rainfall of up to 20 inches and storm surge flooding of nearly 12 feet, Isaac will test the Gulf Coast states, in particular the city of New Orleans, on the seventh anniversary of Hurricane Katrina. Reuters reported that the U.S. Army Corps of Engineers built a $14.5 billion defense flood system designed to protect New Orleans following the devastation of Katrina in 2005.

National Hurricane Center director Rick Knabb told CNN, "Inland flooding historically has been responsible for a lot of fatalities in tropical storms and hurricanes coming ashore. It's not just going to be a coastal event."

Coastal community residents stocked up on food and water as the prepared for Isaac to make landfall, Reuters reported. While many residents began to evacuate New Orleans, some chose to ride out the storm, the report said.

The storm also affected the energy industry as offshore oil rigs and U.S. Gulf Coast refineries shut down. Reuters reports that prices for "international benchmark Brent crude were up 46 cents to $112.72 a barrel" on Tuesday.

Isaac, which could still cause tornadoes along the northern Gulf Coast today, spared Tampa, Fla. where the Republican National Convention is being held. Organizers were forced to rearrange the schedule to accommodate complications caused by the storm.

According to Reuters, Isaac killed at least 22 people in Haiti and the Dominican Republic and caused major flooding and damage to the area. 

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