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| #56869 (Received by flhurricane at: 3:34 AM 15.Nov.2005) TCDAT2 TROPICAL DEPRESSION TWENTY-SEVEN DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 4 AM EST TUE NOV 15 2005 THUS FAR...THE TROPICAL CYCLONE HAS FAILED TO BECOME ANY BETTER ORGANIZED. MOST OF THE DEEP CONVECTION IS LOCATED EAST AND SOUTHEAST OF THE LOW-LEVEL CENTER AND THE OVERALL CLOUD PATTERN IS RAGGED AND AMORPHOUS. SOME DECREASE IN VERTICAL SHEAR IS FORECAST AS GLOBAL MODEL GUIDANCE SHOW AN UPPER-TROPOSPHERIC ANTICYCLONE BUILDING OVER THE CENTRAL CARIBBEAN IN A COUPLE OF DAYS...AND THIS RELAXATION OF SHEAR SHOULD ALLOW SOME STRENGTHENING TO BEGIN. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND SHOWS THE SYSTEM BECOMING A HURRICANE OVER THE WESTERN CARIBBEAN. HOWEVER...GLOBAL GUIDANCE INDICATES THAT THE SHEAR COULD AGAIN INCREASE LATE IN THE PERIOD AS THE TROPICAL CYCLONE MOVES WEST OF THE AXIS OF THE UPPER-LEVEL RIDGE. IT SHOULD BE NOTED THAT THE GFDL INTENSITY FORECASTS HAVE BEEN TRENDING DOWNWARD IN THE LAST SEVERAL RUNS...AND THE SHIPS MODEL RUNS OVER THE PAST 24 HOURS HAVE NOT BEEN FORECASTING THE SYSTEM TO BECOME A HURRICANE. ONE SHOULD ALSO BEAR IN MIND THAT OBJECTIVE OR SUBJECTIVE INTENSITY FORECASTS AT 4-5 DAYS HAVE LITTLE...IF ANY...SKILL. BASED ON MULTI-CHANNEL INFRARED AND MICROWAVE IMAGERY...THE POORLY-DEFINED LOW-CLOUD CENTER IS MOVING A LITTLE FASTER AND JUST SLIGHTLY NORTH OF WEST...285/10. A MID-LEVEL RIDGE IS FORECAST TO REMAIN SITUATED TO THE NORTH OF THE TROPICAL CYCLONE FOR THE NEXT FEW DAYS...WHICH SHOULD MAINTAIN A MOSTLY WESTWARD TRACK FOR A WHILE. THE OFFICIAL TRACK FORECAST IS A LITTLE FASTER THAN THE PREVIOUS ONE BUT SLOWER THAN THE GFDL AND THE DYNAMICAL CONSENSUS DURING THE FIRST HALF OF THE FORECAST PERIOD. DYNAMICAL GUIDANCE SHOWS THE RIDGE WEAKENING IN 3-4 DAYS...SO THE FORWARD SPEED IS LIKELY TO SLOW IN THE LATTER PART OF THE FORECAST PERIOD. BY DAY 5...THE MODELS SHOW THE RIDGE TO THE NORTH ESSENTIALLY OBLITERATED AS A LARGE MID-LATITUDE TROUGH BEGINS TO DROP INTO THE EASTERN UNITED STATES. THIS SHOULD CAUSE SOME NORTHWARD COMPONENT OF MOTION LATE IN THE PERIOD...BUT GIVEN THE UNCERTAINTIES AT THIS TIME THE OFFICIAL TRACK FORECAST ONLY HINTS AT A NORTHWARD TURN. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 15/0900Z 14.6N 66.4W 30 KT 12HR VT 15/1800Z 14.8N 67.8W 30 KT 24HR VT 16/0600Z 15.0N 69.8W 35 KT 36HR VT 16/1800Z 15.2N 71.8W 40 KT 48HR VT 17/0600Z 15.3N 74.0W 45 KT 72HR VT 18/0600Z 15.5N 78.0W 55 KT 96HR VT 19/0600Z 15.5N 80.5W 65 KT 120HR VT 20/0600Z 16.0N 81.5W 65 KT |
