658 
 WTNT44 KNHC 262102
 TCDAT4
  
 TROPICAL STORM ISAAC DISCUSSION NUMBER  23
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
 500 PM EDT SUN AUG 26 2012
 
 ALTHOUGH SATELLITE AND RADAR IMAGES HAVE SUGGESTED THAT THE TROPICAL
 CYCLONE WAS BECOMING A LITTLE BETTER ORGANIZED...AN AIR FORCE
 HURRICANE HUNTER AIRCRAFT INVESTIGATING ISAAC THIS AFTERNOON HAVE
 FOUND THAT THERE HAS BEEN NO STRENGTHENING OF THE STORM. 
 FLIGHT-LEVEL AND SFMR-OBSERVED WINDS SUPPORT AN INTENSITY OF 50 KT. 
 THERE IS STILL A WELL-ESTABLISHED UPPER-LEVEL OUTFLOW PATTERN OVER
 THE SYSTEM...AND VERTICAL SHEAR SHOULD REMAIN FAIRLY LIGHT FOR THE
 NEXT COUPLE OF DAYS.  INTENSIFICATION STILL SEEMS LIKELY AS ISAAC
 MOVES OVER THE EASTERN GULF...AND POSSIBLY OVER THE HIGHER HEAT
 CONTENT OF THE LOOP CURRENT.  THE OFFICIAL INTENSITY FOREAST IS
 CLOSE TO THE LATEST LGEM GUIDANCE...AND NOT MUCH DIFFERENT FROM THE
 PREVIOUS NHC FORECAST.    
 
 ISAAC HAS MOVED A LITTLE TO THE LEFT OF PREVIOUS PROJECTIONS AND
 CENTER FIXES YIELD A 6- TO 12-HOUR AVERAGED MOTION OF 295/15.   THE
 TRACK FORECAST CONTINUES TO BE CHALLENGING.  THE DYNAMICAL MODELS
 SHOW THE TROPICAL STORM/HURRICANE GRADUALLY TURNING TO THE RIGHT
 AND HEADING FOR A BREAK IN THE SUBTROPICAL RIDGE.  HOWEVER...THERE
 ARE SUBSTANTIAL DIFFERENCES AMONG THE MOST RELIABLE MODELS AS TO
 WHERE ISAAC MIGHT CROSS THE NORTHERN GULF COAST.  THE U.K. MET.
 OFFICE AND ECMWF MODELS ARE ABOUT 300 N MI TO THE EAST OF THE GFS
 AT LANDFALL.  IT SHOULD BE NOTED THAT NEARLY ALL OF THE GFS ENSMEBLE  
 MEMBERS ARE EAST OF THE GFS CONTROL TRACK.  BECAUSE OF THE WIDE
 MODEL SPREAD...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.
 
 THE OFFICIAL FORECAST TRACK AND WIND RADII NECESSITATE THE ISSUANCE
 OF A HURRICANE WARNING FOR THE NORTHERN GULF COAST AT THIS TIME. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  26/2100Z 24.2N  82.3W   50 KT  60 MPH
  12H  27/0600Z 25.1N  83.9W   55 KT  65 MPH
  24H  27/1800Z 26.3N  85.9W   60 KT  70 MPH
  36H  28/0600Z 27.7N  87.6W   70 KT  80 MPH
  48H  28/1800Z 28.9N  88.5W   80 KT  90 MPH
  72H  29/1800Z 30.7N  89.5W   85 KT 100 MPH...INLAND
  96H  30/1800Z 32.5N  90.0W   30 KT  35 MPH...INLAND
 120H  31/1800Z 34.5N  90.0W   20 KT  25 MPH...INLAND
  
 $$
 FORECASTER PASCH