118 
 WTNT44 KNHC 291451
 TCDAT4
  
 HURRICANE ISAAC DISCUSSION NUMBER  34
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
 1000 AM CDT WED AUG 29 2012
  
 HURRICANE ISAAC IS INLAND OVER SOUTHEASTERN LOUISIANA NEAR HOUMA.
 THE CYCLONE HAS MAINTAINED AN IMPRESSIVE RADAR SIGNATURE...WHICH
 INCLUDES A RAGGED 40-NMI DIAMETER EYE. CURVED CONVECTIVE RAINBANDS
 HAVE INCREASED IN THE EASTERN SEMICIRCLE...AND DOPPLER RADAR
 VELOCITIES OF NEAR 80 KT OVER WATER SUPPORT KEEPING ISAAC AS A
 MINIMAL HURRICANE FOR THIS ADVISORY. SIMILAR DOPPLER VELOCITIES
 OVER LAND AND OVER LAKE PONTCHARTRAIN SUGGEST WIND GUSTS TO NEAR 80
 KT COULD OCCUR INLAND OVER SOUTHEASTERN LOUISIANA INTO THIS
 AFTERNOON. BY LATE THIS AFTERNOON OR EVENING...HOWEVER...ISAAC IS
 FORECAST TO WEAKEN TO A TROPICAL STORM...AND BECOME A TROPICAL
 DEPRESSION BY THURSDAY NIGHT.
 
 THE INITIAL MOTION ESTIMATE IS 310/5. ISAAC IS EXPECTED TO MOVE
 SLOWLY NORTHWESTWARD THROUGH A WEAKNESS IN THE SUBTROPICAL RIDGE
 FOR THE NEXT 24 HOURS...AND THEN TURN NORTH-NORTHWESTWARD AND
 NORTHWARD AROUND THE WESTERN PERIPHERY OF THE RIDGE BY 36 AND 48
 HOURS...RESPECTIVELY. BY 72 HOURS...ISAAC IS FORECAST TO BECOME A
 POST-TROPICAL REMNANT LOW PRESSURE SYSTEM THAT SHOULD MOVE
 NORTHEASTWARD TO EAST-NORTHEASTWARD WHEN IT WILL BE CAUGHT UP IN
 WEAK MID-LATITUDE WESTERLIES. THERE ARE CURRENTLY NO INDICATIONS IN
 ANY OF THE MODEL GUIDANCE SUGGESTING THAT ISAAC WILL TAP INTO ANY
 BAROCLINIC ENERGY SOURCES THAT COULD RESULT IN EXTRATROPICAL
 STRENGTHENING OVER THE CENTRAL UNITED STATES. THE OFFICIAL TRACK
 FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY TRACK AND IS JUST EAST
 OF THE MODEL CONSENSUS.
  
 SINCE ISAAC IS FORECAST TO MOVE SLOWLY OVER THE NEXT 24-36 HOURS...
 THERE WILL BE A PROLONGED THREAT OF FLOODING FROM HEAVY RAINS OVER
 THE NORTHERN GULF COAST AREA AND THE SOUTH-CENTRAL UNITED STATES.
  
 NATIONAL OCEAN SERVICE TIDE GAGES INDICATE THAT STORM SURGE HEIGHTS
 OF 6 TO 8 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.
  
 A SPECIAL THANKS TO THE CREWS OF THE AIR FORCE RESERVE AND NOAA
 HURRICANE HUNTERS WHO FLEW A TOTAL OF 34 HAZARDOUS MISSIONS INTO
 ISAAC...WHICH RESULTED IN AN IMPRESSIVE TOTAL OF 95 CENTER FIXES.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  29/1500Z 29.6N  90.7W   65 KT  75 MPH...INLAND
  12H  30/0000Z 30.2N  91.4W   55 KT  65 MPH...INLAND
  24H  30/1200Z 31.2N  92.2W   45 KT  50 MPH...INLAND
  36H  31/0000Z 32.8N  93.1W   30 KT  35 MPH...INLAND
  48H  31/1200Z 34.6N  93.5W   25 KT  30 MPH...INLAND
  72H  01/1200Z 38.0N  92.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
  96H  02/1200Z 40.0N  89.0W   15 KT  15 MPH...POST-TROP/REMNT LOW
 120H  03/1200Z 41.0N  85.0W   15 KT  15 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER STEWART