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#56815 (Received by flhurricane at: 3:55 PM 14.Nov.2005) TCDAT2 TROPICAL DEPRESSION TWENTY-SEVEN DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 4 PM EST MON NOV 14 2005 THE SATELLITE PRESENTATION OF THE DEPRESSION HAS DETERIORATED SINCE THIS MORNING. THE LOW LEVEL CENTER IS EXPOSED AND MORE CLEARLY DISCERNIBLE. DEEP CONVECTION PERSISTS BUT ONLY ON THE EASTERN SIDE OF THE CIRCULATION DUE TO CONTINUING WESTERLY SHEAR. ESTIMATING THE INTENSITY VIA SATELLITE IMAGERY IS HIGHLY SENSITIVE TO THE CENTER POSITION... BUT THE DISTANCE OF THE EXPOSED SWIRL FROM THE CONVECTION PROVIDES CONFIDENCE THAT THE CYCLONE REMAINS A TROPICAL DEPRESSION. 18Z DVORAK T NUMBERS FROM TAFB AND SAB ARE 2.0... AND THE ADVISORY INTENSITY IS KEPT AT 30 KT. THE DEPRESSION CONTINUES WEST-NORTHWESTWARD AT ABOUT 290/7. A MID-TROPOSPHERIC RIDGE IS FORECAST BY THE DYNAMICAL MODELS TO PERSIST THROUGHOUT THE FIVE DAY FORECAST PERIOD OVER THE WESTERN ATLANTIC... ALTHOUGH IT WILL PROBABLY WEAKEN BEYOND DAY THREE AS A MID-LATITUDE TROUGH DEEPENS OVER THE EASTERN UNITED STATES. THIS PATTERN SHOULD FORCE THE CYCLONE ON A GENERAL WESTWARD TRACK... BUT LIKELY SLOW ENOUGH FOR IT TO STILL BE IN THE CARIBBEAN SEA IN FIVE DAYS. SOME DISAGREEMENT REMAINS ON THE LATITUDE AT WHICH THE CYCLONE WILL MOVE... DUE TO DIFFERENCES AMONG THE MODELS IN HOW STRONG THE CIRCULATION WILL BECOME. THE GFDL AND NOGAPS DEPICT A DEEPER SYSTEM AND ARE ON THE NORTH SIDE OF THE GUIDANCE ENVELOPE... WHILE THE GFS AND UKMET HAVE A WEAKER SYSTEM FARTHER SOUTH. THE OFFICIAL FORECAST IS UNCHANGED FROM THE PREVIOUS ADVISORY AND VERY CLOSE TO THE MODEL CONSENSUS. THE TRACK AND INTENSITY FORECASTS MAKE THE ASSUMPTION THAT THE CYCLONE WILL SURVIVE THE SHEAR THAT IS EXPECTED TO CONTINUE OVER THE EASTERN CARIBBEAN DURING THE NEXT DAY OR TWO. THE ENVIRONMENT COULD THEREAFTER BECOME A LITTLE MORE CONDUCIVE FOR STRENGTHENING. IN PARTICULAR... AN UPPER-LEVEL ANTICYCLONE IS FORECAST BY MOST OF THE DYNAMICAL MODELS TO DEVELOP IN A COUPLE OF DAYS OVER THE WEST-CENTRAL CARIBBEAN SEA... WHERE OCEAN TEMPERATURES ARE QUITE WARM NEAR 29C. THE SHIPS GUIDANCE FORECASTS A TROPICAL STORM IN 36 HOURS AND A PEAK AT 55 KT IN 96 HOURS... WHILE THE GFDL CONTINUES TO INSIST THE CYCLONE WILL BECOME A MAJOR HURRICANE IN 3-4 DAYS. THE OFFICIAL FORECAST REMAINS IN BETWEEN... BUT MUCH CLOSER TO THE SHIPS... AND IS JUST AN UPDATE OF THE PREVIOUS ADVISORY. GIVEN THE DIFFERENCES IN THE INTENSITY GUIDANCE... AND THE CURRENT DISORGANIZATION OF THE SYSTEM... THIS INTENSITY FORECAST IS EVEN MORE UNCERTAIN THAN USUAL. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 14/2100Z 14.2N 64.5W 30 KT 12HR VT 15/0600Z 14.6N 65.8W 35 KT 24HR VT 15/1800Z 15.1N 67.5W 40 KT 36HR VT 16/0600Z 15.4N 69.4W 40 KT 48HR VT 16/1800Z 15.5N 71.3W 45 KT 72HR VT 17/1800Z 15.5N 75.0W 50 KT 96HR VT 18/1800Z 15.5N 78.5W 60 KT 120HR VT 19/1800Z 15.5N 80.5W 65 KT |