Monday, August 27, 2012

Seven Years To The Day?
One New Orleans Levee, Then and Now

The repaired Industrial Canal Levee in the Lower Ninth Ward. Top image: As repaired in 2006, Bottom image: September 12, 2005. National Geographic Article, 10/8/2010 "In Katrina's Wake"

11:00 AM EDT 8/27/12 (Forecaster Jason M. and Mr. Foot) Tropical Storm Isaac is still battling dry air to its west, and maximum sustained winds remain at 65 mph as of the 11 AM NHC advisory. Strengthening is still expected later today, and the storm could reach hurricane strength by tonight if not sooner. What we know:
  • Isaac's current movement is towards the northwest at 14 mph. All those along the Louisiana and Mississippi coast are at risk for a direct hit late Tuesday into Wednesday. The date would be August 29, seven years to the day of Katrina's second landfall.
  • Tropical Storm to Hurricane force conditions could extend for a 24 hour period or greater in these areas.
IDEAS ON INTENSITY AND SPEED The storm may slow down some, which will prolong effects along the coast. The eventual intensity at landfall is still uncertain. The NHC is currently projecting it to be at category 1 intensity, but we cannot rule out Isaac being more intense. Even at Category 1 intensity, this will still be a high impact situation for southeastern Louisiana. Additional graphics and analysis imagery are available at our Tropical Zone on this website.


(This graphic shows the consensus track among several hurricane track models. As you can see, the highest confidence right now is for a landfall in LA)

NOT THE WORSE CASE SCENARIO? While Katrina was catastrophic by any measure, the real concern among some engineers and researchers is that Isaac represents a scenario that could rival a storm in the distant past that today would be even worse than Katrina. It was the 1812 Hurricane, uncovered through in-depth research by a Geographer at the University of South Carolina in this USC article. It is a study of history, culture, meteorology and geo-hazards all wrapped into one situation we hope does not repeat. 

Overnight satellite image of Isaac on 8/27/12
8 AM EDT 8/27/12 (Tropical Advisor Forrest) The 8 AM NHC update locates Isaac at 25.7N, 84.7 W or 360 miles SE of the Mississippi River, moving to the WNW at 14 MPH, with maximum sustained winds of 65 MPH and a central pressur
e of 988 mb. What we know:

  • The central pressure is slowly dropping, an indicator of strengthening, and Isaac is forecast to strengthen. 
  • Effects from Isaac will be felt throughout the Gulf region - rain and winds in FL, with a tornado watch posted for south and central FL - rising tides along the central Gulf coast. 
  • The NHC forecast has Isaac turning more to the NW and making landfall around the LA/MS border, but given the large size of this storm, a large area will be affected.



A HURRICANE WARNING is in effect for: East of Morgan City, LA to Destin, FL, including Lake Pontchartrain and Lake Maurepas. A Hurricane Watch is in effect for Intracoastal City to Morgan City, LA.




A TROPICAL STORM WARNING is in effect for the Florida peninsula from Ocean Reef southward on the East Coast and from Tarpon Springs southward on the west coast, including the Dry Tortugas and Florida Bay, East of Destin, FL to the Swanee River and from Intracoastal City to Morgan City, LA




PREPARE NOW. All preparations to protect life and property should be rushed to completion as safely as possible, as well as to heed local evacuation procedures. Areas south of I-10 and low lying areas from Alabama to LA are of particular concern for significant storm surge flooding likely to exceed 6 feet.

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