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Tropical Depression TWENTY-SEVEN
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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
$$
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