000 WTNT44 KNHC 261459 TCDAT4 TROPICAL STORM ISAAC DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 1100 AM EDT SUN AUG 26 2012 VISIBLE SATELLITE AND IMAGERY SUGGEST THAT THE TROPICAL CYCLONE IS GRADUALLY BECOMING BETTER ORGANIZED. THERE ARE INDICATIONS OF INNER CORE DEVELOPMENT WITH INCREASED CONVECTION NEAR AND OVER THE CENTER...AND A PARTIAL EYEWALL IS IN EVIDENCE ON RADAR IMAGERY. THE BANDING FEATURES HAVE BECOME MORE DISTINCT OVER THE NORTHERN AND EASTERN SEMICIRCLES OF THE CIRCULATION. THE CURRENT INTENSITY ESTIMATE IS HELD AT 55 KT PENDING OBSERVATIONS FROM AN AIR FORCE HURRICANE HUNTER AIRCRAFT THAT SHOULD BE IN THE CENTER SHORTLY. ISAAC CONTINUES TO EXHIBIT A WELL-DEFINED UPPER-LEVEL OUTFLOW PATTERN...AND GRADUAL STRENGTHENING IS LIKELY AS THE CYCLONE TRAVERSES THE EASTERN GULF OF MEXICO OVER THE NEXT COUPLE OF DAYS. THE OFFICIAL WIND SPEED FORECAST IS SIMILAR TO THE PREVIOUS NHC FORECAST AND IS ALSO CLOSE TO THE LATEST STATISTICAL-DYNAMICAL GUIDANCE. THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE... THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY 3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST. THROUGHOUT THE PERIOD...IT IS IMPORTANT NOT TO FOCUS ON THE EXACT FORECAST TRACK SINCE SIGNIFICANT HAZARDS EXTEND WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 23.9N 80.8W 55 KT 65 MPH 12H 27/0000Z 25.0N 82.7W 65 KT 75 MPH 24H 27/1200Z 26.1N 84.8W 70 KT 80 MPH 36H 28/0000Z 27.4N 86.4W 75 KT 85 MPH 48H 28/1200Z 28.5N 87.6W 80 KT 90 MPH 72H 29/1200Z 30.5N 89.0W 90 KT 105 MPH 96H 30/1200Z 32.5N 89.5W 30 KT 35 MPH...INLAND 120H 31/1200Z 34.5N 89.5W 20 KT 25 MPH...INLAND $$ FORECASTER PASCH/ROBERTS