Tropical Depression SIXTEEN

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TROPICAL DEPRESSION SIXTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL162007
1100 AM EDT SUN OCT 28 2007
 
THE APPEARANCE OF THE CYCLONE ON SATELLITE IMAGERY HAS BECOME FAIRLY
IMPRESSIVE...FOR A TROPICAL DEPRESSION.  INFRARED CLOUD TOP
TEMPERATURES ARE QUITE COLD OVER A LARGE AREA...AND THERE IS EVEN A
BAND EXTENDING SOUTHWARD...GIVING THE SYSTEM A COMMA SHAPE.  THE
DEPRESSION CERTAINLY SEEMS ON THE VERGE OF BECOMING A TROPICAL
STORM...BUT THE AVAILABLE DATA AT THE MOMENT ARE INCONCLUSIVE AS TO
WHETHER OR NOT THIS HAS YET OCCURRED.  THE EASTERN EDGE OF A
QUIKSCAT PASS FROM ABOUT 1115Z ONLY CAUGHT A PORTION OF THE
CIRCULATION AND DID NOT RETRIEVE ANY RELIABLE WINDS OF TROPICAL
STORM FORCE.  DVORAK INTENSITY ESTIMATES ARE UNCHANGED SINCE 06Z
AND THE ADVISORY INTENSITY REMAINS 30 KT.  AN AIR FORCE RESERVE
HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO DEPART SHORTLY TO
INVESTIGATE THE DEPRESSION AND GIVE US A BETTER HANDLE ON THE
INTENSITY.
 
THE DEPRESSION CONTINUES WEST-NORTHWESTWARD TO THE SOUTH OF A LOW-
TO MID-LEVEL RIDGE OVER THE WESTERN ATLANTIC.  ALL OF THE MODELS
FORECAST THE MID-LEVEL RIDGE TO WEAKEN DURING THE NEXT DAY OR TWO AS
A SHORT WAVE TROUGH MOVES INTO THE SOUTHEASTERN UNITED STATES AND
HEIGHTS RISE FARTHER TO THE EAST.  SOME OF THE TRACK MODELS...IN
PARTICULAR THE GFDL AND HWRF...RESPOND TO THIS PATTERN CHANGE BY
FORECASTING A RELATIVELY QUICK RECURVATURE OUT OF THE CARIBBEAN VIA
EASTERN CUBA.  MOST OF THE GLOBAL MODELS...HOWEVER...FORECAST A
SLOWER MOTION GENERALLY TOWARD THE WEST-NORTHWEST AND KEEP THE
CYCLONE SOUTH OF CUBA BETWEEN 3 AND 5 DAYS.  THE NEW OFFICIAL TRACK
FORECAST FOLLOWS THE SAME PATH AS IN THE PREVIOUS ADVISORY...BUT AT
A SLIGHTLY SLOWER PACE IN DEFERENCE TO THE GLOBAL MODELS.
 
THE HUGE UNCERTAINTIES IN THE TRACK FORECAST ALSO TRANSLATE INTO A
VERY CHALLENGING INTENSITY PROGNOSIS.  IF THE OFFICIAL TRACK WERE
TO VERIFY PERFECTLY...THE CIRCULATION CENTER WOULD REMAIN OVER
WATER FOR ABOUT FOUR MORE DAYS BEFORE CROSSING CUBA.  SINCE THE
UPPER-LEVEL LOW CURRENTLY NEAR THE DEPRESSION IS FORECAST TO
DISSIPATE WITHIN A DAY OR TWO...THE RESULTING DECREASE IN WIND
SHEAR WOULD PROBABLY ALLOW FOR SOME STRENGTHENING.  IF...HOWEVER...
THE CYCLONE GOES FARTHER NORTH AND EAST...LAND INTERACTION WOULD
OCCUR SOONER AND PERHAPS FOR A LONGER PERIOD AND COULD LIMIT
STRENGTHENING.  FINALLY...A TRACK FARTHER SOUTH AND WEST COULD
PLACE THE CYCLONE WITHIN A WEAKER-SHEAR ENVIRONMENT AND ALLOW FOR
MORE STRENGTHENING THAN FORECAST.  IF THE CYCLONE DOES RECURVE
TOWARD THE WESTERN ATLANTIC IN A FEW DAYS...THE UPPER-LEVEL
WESTERLIES NORTH OF CUBA ARE FORECAST BY THE GLOBAL MODELS TO BE
STRONG AND NOT CONDUCIVE FOR THE CYCLONE TO STRENGTHEN...AT LEAST
NOT AS A TROPICAL CYCLONE.  THE NEW OFFICIAL INTENSITY FORECAST
PEAKS JUST A LITTLE HIGHER THAN THE PREVIOUS ADVISORY AND IS
BETWEEN THE LGEM AND SHIPS SOLUTIONS...AND MUCH LESS THAN THE GFDL
AND HWRF FORECASTS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/1500Z 16.5N  72.5W    30 KT
 12HR VT     29/0000Z 17.0N  73.4W    35 KT
 24HR VT     29/1200Z 18.0N  75.0W    40 KT
 36HR VT     30/0000Z 19.0N  76.5W    45 KT
 48HR VT     30/1200Z 20.0N  78.0W    50 KT
 72HR VT     31/1200Z 21.0N  79.5W    55 KT
 96HR VT     01/1200Z 22.0N  80.0W    50 KT...INLAND OVER CUBA
120HR VT     02/1200Z 24.0N  78.0W    45 KT...OVER WATER
 
$$
FORECASTER KNABB
 
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