648 
 WTNT44 KNHC 290858
 TCDAT4
  
 HURRICANE ISAAC DISCUSSION NUMBER  33
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
 400 AM CDT WED AUG 29 2012
  
 AFTER REMAINING QUASI-STATIONARY FOR SEVERAL HOURS...AIRCRAFT AND
 RADAR DATA INDICATE THAT THE CENTER OF ISAAC MADE A SECOND LANDFALL
 NEAR PORT FOURCHON LOUISIANA AND IS BEGINNING TO MOVE INLAND OVER
 SOUTHEAST LOUISIANA.  OBSERVATIONS FROM THE HURRICANE HUNTER
 AIRCRAFT INDICATE THAT THE EYE IS OPEN OVER THE WESTERN PORTION OF
 THE CIRCULATION...AND THE RADAR PRESENTATION HAS BECOME MORE
 ASYMMETRIC OVER THE PAST COUPLE OF HOURS.  HOWEVER...THE RADAR
 REFLECTIVITIES INDICATE THAT CONVECTION HAS BECOME STRONGER OVER
 THE NORTHERN AND EASTERN PORTIONS OF THE CYCLONE...AND THE AIRCRAFT
 REPORTED THAT THE CENTRAL PRESSURE REMAINS QUITE LOW.  THE CURRENT
 INTENSITY IS HELD AT 70 KT...BUT WEAKENING IS IMMINENT NOW THAT THE
 CENTER HAS BEGUN TO MOVE OVER LAND.  FOR THE NEXT 24 HOURS OR
 SO...THE OFFICIAL INTENSITY FORECAST SHOWS A SOMEWHAT SLOWER RATE
 OF WEAKENING THAN THAT GIVEN BY THE INLAND DECAY MODEL DUE TO THE
 SWAMPY TERRAIN THAT THE SYSTEM WILL TRAVERSE. 
 
 SINCE THE SYSTEM HAS ONLY BEGUN TO MOVE RECENTLY...THE INITIAL
 MOTION IS AN UNCERTAIN 300/7.  ISAAC IS CURRENTLY MOVING THROUGH A
 WEAKNESS IN THE SUBTROPICAL RIDGE.  OVER THE NEXT FEW DAYS...A
 MID-LEVEL ANTICYLONE SHIFTS EASTWARD OVER THE CENTRAL AND EASTERN
 UNITED STATES.  AS A RESULT...ISAAC SHOULD GRADUALLY TURN TOWARD
 THE NORTH AND NORTHEAST DURING THE FORECAST PERIOD.  NEAR THE END
 OF THE PERIOD...POST-TROPICAL ISAAC SHOULD MOVE EAST-NORTHEASTWARD
 IN THE FLOW BETWEEN THE MID-LATITUDE WESTERLIES AND THE
 AFOREMENTIONED ANTICYLONE.  THE OFFICIAL TRACK FORECAST IS SIMILAR
 TO THE PREVIOUS ONE AND CLOSE TO THE MODEL CONSENSUS.
 
 SINCE THE SYSTEM IS LIKELY TO MOVE SLOWLY OVER THE NEXT 24 HOURS OR
 SO...THERE IS A CONTINUED THREAT OF FLOODING FROM HEAVY RAINS OVER
 THE NORTHERN GULF COAST AREA.
 
 NATIONAL OCEAN SERVICE TIDE GAUGES INDICATE THAT STORM SURGE HEIGHTS
 OF 6 TO 10 FEET ARE STILL OCCURRING ALONG PORTIONS OF THE COAST OF
 SOUTHEASTERN LOUISIANA AND MISSISSIPPI.  GIVEN THE LONG DURATION
 OF ONSHORE FLOW IN THESE AREAS...WATER LEVELS ARE EXPECTED TO REMAIN
 HIGH THROUGH TODAY.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  29/0900Z 29.2N  90.5W   70 KT  80 MPH...INLAND
  12H  29/1800Z 29.7N  91.1W   65 KT  75 MPH...INLAND
  24H  30/0600Z 30.5N  91.8W   50 KT  60 MPH...INLAND
  36H  30/1800Z 31.8N  92.8W   30 KT  35 MPH...INLAND
  48H  31/0600Z 33.6N  93.7W   25 KT  30 MPH...INLAND
  72H  01/0600Z 37.5N  93.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
  96H  02/0600Z 39.5N  90.0W   15 KT  15 MPH...POST-TROP/REMNT LOW
 120H  03/0600Z 40.5N  86.0W   15 KT  15 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER PASCH/ROBERTS