241 
 WTNT44 KNHC 270250
 TCDAT4
  
 TROPICAL STORM ISAAC DISCUSSION NUMBER  24
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
 1100 PM EDT SUN AUG 26 2012
  
 SATELLITE IMAGERY HAS SHOWN AN INCREASE IN THE AREA OF COLD CLOUD
 TOPS NEAR THE CENTER OF ISAAC.  HOWEVER...THERE HAS NOT BEEN ANY
 SIGNIFICANT CHANGE IN ORGANIZATION IN RADAR DATA FROM KEY WEST
 THIS EVENING. IN FACT...THE AIRCRAFT FIXES HAVE BEEN NEAR THE
 SOUTHEASTERN EDGE OF THE CONVECTIVE CLUSTER SEEN IN BOTH SATELLITE
 AND RADAR IMAGERY.  AN EARLIER SHIP OBSERVATION AND SFMR
 MEASUREMENTS OF 50-55 KT SUPPORTED INCREASING THE INTENSITY TO 55
 KT ON THE INTERMEDIATE ADVISORY.  SINCE THAT TIME...THE AIRCRAFT
 HAS NOT FOUND ANY STRONGER WINDS SO THE INITIAL WIND SPEED REMAINS
 UNCHANGED.  THE LARGE SCALE ENVIRONMENTAL FACTORS...WARM
 WATERS...AND A CONDUCIVE UPPER-AIR PATTERN FAVOR STRENGTHENING
 DURING THE NEXT COUPLE OF DAYS. HOWEVER...THE LACK OF AN INNER CORE
 AND LARGE WIND FIELD COULD CONTINUE TO BE IMPEDING FACTORS FOR
 SIGNIFICANT STRENGTHENING IN THE SHORT TERM.  THE NHC INTENSITY
 FORECAST SHOWS A GRADUAL INCREASE IN WIND SPEED DURING THE NEXT 12
 HOURS OR SO...FOLLOWED BY MORE STEADY STRENGTHENING.  THE OFFICIAL
 FORECAST IS CLOSE TO THE SHIPS/LGEM GUIDANCE AND THE INTENSITY
 CONSENSUS.
  
 AIRCRAFT AND RADAR CENTER FIXES INDICATE THAT ISAAC JOGGED WESTWARD
 AND SLOWED DOWN THIS EVENING.  HOWEVER...THE LONGER TERM MOTION IS
 285/12 KT.  THE MODELS SHOW ISAAC TURNING TOWARD THE NORTHWEST INTO
 A BREAK IN THE SUBTROPICAL RIDGE.  ALTHOUGH THE MODELS AGREE ON
 THIS TURN...THERE IS AN UNUSUALLY LARGE SPREAD IN THE TRACK GUIDANCE
 AFTER 24 HOURS.  THE SPREAD OF LANDFALL LOCATIONS ALONG THE NORTHERN
 GULF COAST RANGES FROM THE TEXAS/LOUISIANA BORDER EASTWARD TO THE
 ALABAMA/FLORIDA BORDER WITH THE HWRF...GFDL...AND GFS NEAR THE
 WESTERN EDGE AND THE UKMET AND ECMWF ALONG THE EASTERN EDGE OF THE
 ENVELOPE.  OVERALL...THE CONSENSUS HAS SHIFTED A LITTLE WESTWARD
 AND THE OFFICIAL FORECAST AS BEEN MOVED IN THAT DIRECTION.  THE NHC
 FORECAST IS BETWEEN THE ECMWF AND GFS ENSEMBLE MEANS AND NEAR THE
 HFIP MULTI-MODEL CONSENSUS.  BECAUSE OF THE VERY LARGE SPREAD IN
 THE GUIDANCE...THERE CONTINUES TO BE GREATER THAN USUAL TRACK
 FORECAST UNCERTAINTY.
  
 THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT
 FORECAST TRACK DUE TO FORECAST UNCERTAINTIES AND THE FACT THAT
 SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER.
   
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  27/0300Z 24.2N  82.9W   55 KT  65 MPH
  12H  27/1200Z 25.2N  84.8W   60 KT  70 MPH
  24H  28/0000Z 26.5N  86.7W   70 KT  80 MPH
  36H  28/1200Z 27.9N  88.3W   80 KT  90 MPH
  48H  29/0000Z 28.9N  89.3W   85 KT 100 MPH
  72H  30/0000Z 30.6N  90.3W   70 KT  80 MPH...INLAND
  96H  31/0000Z 33.0N  91.0W   30 KT  35 MPH...INLAND
 120H  01/0000Z 36.0N  91.0W   20 KT  25 MPH...INLAND
  
 $$
 FORECASTER BROWN