000 WTPZ44 KNHC 190257 TCDEP4 TROPICAL STORM DORA DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042011 800 PM PDT MON JUL 18 2011 THE CLOUD PATTERN ASSOCIATED WITH DORA HAS CONTINUED TO IMPROVE IN ORGANIZATION THIS EVENING. THE CONVECTIVE BANDING HAS INCREASED SINCE THIS AFTERNOON...AND A CDO APPEARS TO BE FORMING. RECENT 37 GHZ SSMIS MICROWAVE IMAGES ALSO SHOW INCREASED INNER-CORE STRUCTURE WITH THE BEGINNINGS OF A LOW-LEVEL RING FEATURE. THE LATEST DVORAK T-NUMBERS FROM TAFB AND SAB ARE 3.0 AND 2.5... RESPECTIVELY...AND OBJECTIVE T-NUMBERS FROM UW-CIMSS ARE 3.0. THE ADVISORY INTENSITY OF 50 KT IS BASED ON THE TAFB AND OBJECTIVE DVORAK ESTIMATES AND THE IMPROVED ORGANIZATION. THE CYCLONE APPEARS TO BE IN A VERY FAVORABLE ENVIRONMENT FOR STRENGTHENING...WITH LOW VERTICAL SHEAR AND WARM SSTS. MYSTERIOUSLY...THE INTENSITY GUIDANCE DOES NOT STRENGTHEN DORA AS MUCH AS I WOULD EXPECT. THE SHIPS/LGEM GUIDANCE SHOWS A PEAK INTENSITY OF AROUND 90 KT IN 48-60 HOURS WHILE THE GFDL/HWRF ARE ONLY SLIGHTLY HIGHER. THE NHC FORECAST REMAINS ABOVE THE GUIDANCE DURING THE FIRST 24-36 AND IS IN CLOSEST AGREEMENT TO THE MORE AGGRESSIVE FLORIDA STATE SUPERENSEMBLE. AFTER 72 HOURS...DORA WILL BE APPROACHING COOLER WATER AND A MORE STABLE ENVIRONMENT. WEAKENING SHOULD COMMENCE BY THAT TIME. THE INITIAL MOTION REMAINS 280/12. THE LARGE HIGH PRESSURE RIDGE OVER THE CENTRAL UNITED STATES SHOULD KEEP DORA ON A WEST-NORTHWEST HEADING DURING THE NEXT COUPLE OF DAYS. DURING THAT TIME...THE TRACK GUIDANCE IS IN VERY GOOD AGREEMENT. BEYOND 72 HOURS...THE RIDGE IS FORECAST TO SLIDE EASTWARD AND WEAKEN...WHICH SHOULD CAUSE DORA TO SLOW DOWN AND BEGIN TO GAIN MORE LATITUDE. THE MODEL GUIDANCE HAS SHIFTED EASTWARD AT DAYS 3-5 WHICH REQUIRED A SMALL EASTWARD ADJUSTMENT TO THE OFFICIAL FORECAST. IT SHOULD BE NOTED THAT THE GFDL AND HWRF MODELS ARE ALONG THE RIGHT SIDE OF THE GUIDANCE ENVELOPE...BUT HAVE RECENTLY EXHIBITED A RIGHT-OF-TRACK BIAS FOR SYSTEMS SOUTH OF MEXICO. THEREFORE...THE OFFICIAL FORECAST REMAINS LEFT OF TVCN AND CLOSER TO THE GFS AND ECMWF SOLUTIONS. THE WIND RADII WERE ADJUSTED OUTWARD BASED A 0000 UTC SHIP OBSERVATION TO THE NORTHWEST OF THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 11.1N 94.1W 50 KT 60 MPH 12H 19/1200Z 11.6N 96.1W 60 KT 70 MPH 24H 20/0000Z 12.5N 98.9W 75 KT 85 MPH 36H 20/1200Z 13.6N 101.5W 90 KT 105 MPH 48H 21/0000Z 14.9N 103.8W 105 KT 120 MPH 72H 22/0000Z 17.3N 107.5W 105 KT 120 MPH 96H 23/0000Z 19.0N 110.0W 80 KT 90 MPH 120H 24/0000Z 21.0N 112.5W 55 KT 65 MPH $$ FORECASTER BROWN 000 WTPZ44 KNHC 190257 TCDEP4 TROPICAL STORM DORA DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042011 800 PM PDT MON JUL 18 2011 THE CLOUD PATTERN ASSOCIATED WITH DORA HAS CONTINUED TO IMPROVE IN ORGANIZATION THIS EVENING. THE CONVECTIVE BANDING HAS INCREASED SINCE THIS AFTERNOON...AND A CDO APPEARS TO BE FORMING. RECENT 37 GHZ SSMIS MICROWAVE IMAGES ALSO SHOW INCREASED INNER-CORE STRUCTURE WITH THE BEGINNINGS OF A LOW-LEVEL RING FEATURE. THE LATEST DVORAK T-NUMBERS FROM TAFB AND SAB ARE 3.0 AND 2.5... RESPECTIVELY...AND OBJECTIVE T-NUMBERS FROM UW-CIMSS ARE 3.0. THE ADVISORY INTENSITY OF 50 KT IS BASED ON THE TAFB AND OBJECTIVE DVORAK ESTIMATES AND THE IMPROVED ORGANIZATION. THE CYCLONE APPEARS TO BE IN A VERY FAVORABLE ENVIRONMENT FOR STRENGTHENING...WITH LOW VERTICAL SHEAR AND WARM SSTS. MYSTERIOUSLY...THE INTENSITY GUIDANCE DOES NOT STRENGTHEN DORA AS MUCH AS I WOULD EXPECT. THE SHIPS/LGEM GUIDANCE SHOWS A PEAK INTENSITY OF AROUND 90 KT IN 48-60 HOURS WHILE THE GFDL/HWRF ARE ONLY SLIGHTLY HIGHER. THE NHC FORECAST REMAINS ABOVE THE GUIDANCE DURING THE FIRST 24-36 AND IS IN CLOSEST AGREEMENT TO THE MORE AGGRESSIVE FLORIDA STATE SUPERENSEMBLE. AFTER 72 HOURS...DORA WILL BE APPROACHING COOLER WATER AND A MORE STABLE ENVIRONMENT. WEAKENING SHOULD COMMENCE BY THAT TIME. THE INITIAL MOTION REMAINS 280/12. THE LARGE HIGH PRESSURE RIDGE OVER THE CENTRAL UNITED STATES SHOULD KEEP DORA ON A WEST-NORTHWEST HEADING DURING THE NEXT COUPLE OF DAYS. DURING THAT TIME...THE TRACK GUIDANCE IS IN VERY GOOD AGREEMENT. BEYOND 72 HOURS...THE RIDGE IS FORECAST TO SLIDE EASTWARD AND WEAKEN...WHICH SHOULD CAUSE DORA TO SLOW DOWN AND BEGIN TO GAIN MORE LATITUDE. THE MODEL GUIDANCE HAS SHIFTED EASTWARD AT DAYS 3-5 WHICH REQUIRED A SMALL EASTWARD ADJUSTMENT TO THE OFFICIAL FORECAST. IT SHOULD BE NOTED THAT THE GFDL AND HWRF MODELS ARE ALONG THE RIGHT SIDE OF THE GUIDANCE ENVELOPE...BUT HAVE RECENTLY EXHIBITED A RIGHT-OF-TRACK BIAS FOR SYSTEMS SOUTH OF MEXICO. THEREFORE...THE OFFICIAL FORECAST REMAINS LEFT OF TVCN AND CLOSER TO THE GFS AND ECMWF SOLUTIONS. THE WIND RADII WERE ADJUSTED OUTWARD BASED A 0000 UTC SHIP OBSERVATION TO THE NORTHWEST OF THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 11.1N 94.1W 50 KT 60 MPH 12H 19/1200Z 11.6N 96.1W 60 KT 70 MPH 24H 20/0000Z 12.5N 98.9W 75 KT 85 MPH 36H 20/1200Z 13.6N 101.5W 90 KT 105 MPH 48H 21/0000Z 14.9N 103.8W 105 KT 120 MPH 72H 22/0000Z 17.3N 107.5W 105 KT 120 MPH 96H 23/0000Z 19.0N 110.0W 80 KT 90 MPH 120H 24/0000Z 21.0N 112.5W 55 KT 65 MPH $$ FORECASTER BROWN