Tropical Depression SIXTEEN

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TROPICAL DEPRESSION SIXTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT TUE SEP 06 2005
 
DATA FROM THE WSR-88D AT MELBOURNE SHOWS THAT TROPICAL DEPRESSION
SIXTEEN HAS A CIRCULATION CENTER ELONGATED WEST-SOUTHWEST TO
EAST-NORTHEAST.  THE EARLIER NOAA AIRCRAFT FLIGHT FOUND MAXIMUM
FLIGHT-LEVEL WINDS OF 27 KT MORE THAN 60 N MI AWAY FROM THE BROAD
CENTER.  BASED ON A 27 KT WIND FROM BUOY 41010 AND SATELLITE
INTENSITY ESTIMATES...THE INITIAL INTENSITY IS INCREASED TO 30 KT. 
IT SHOULD BE NOTED THAT DURING THE LAST 30 MIN OR SO...THE
MELBOURNE RADAR HINTS THAT A BETTER DEFINED INNER CORE MAY BE
FORMING.  THE NEXT NOAA AIRCRAFT WILL ARRIVE IN THE CYCLONE AT
ABOUT 06Z TO SEE IF THAT IS THE CASE.

THE INITIAL MOTION IS AN UNCERTAIN 330/3...WITH THE RADAR DATA
HINTING AT A FASTER FORWARD MOTION.  TRACK GUIDANCE AGREES ON A
SLOW NORTHWESTWARD MOTION FOR 48 HR OR SO...THEN THERE IS SERIOUS
DIVERGENCE.  THE GFDL...GFDN...ECMWF...AND BAMS TURN THE CYCLONE
WESTWARD ACROSS THE FLORIDA PENINSULA INTO THE GULF OF MEXICO.  THE
GFS...UKMET...NOGAPS...CANADIAN...AND BAMD TURN IT NORTHWARD AND
EVEN NORTHEASTWARD OFFSHORE OF THE SOUTHEASTERN UNITED STATES.  THE
MODELS ARE SIMILAR IN THE OVERALL PATTERN...WITH THE CYCLONE
BETWEEN TWO SEGMENTS OF THE SUBTROPICAL RIDGE AS A STRONG
DEEP-LAYER TROUGH MOVES OFF THE U.S. EAST COAST.  THE DIFFERENT
TRACKS RESULT MAINLY FROM WHICH SEGMENT OF THE RIDGE WILL BE
STRONGER...AND IT IS NOT APPARENT AT THIS TIME WHICH CLUSTER OF
GUIDANCE WILL BE CORRECT.  THEREFORE...THE FORECAST TRACK WILL
SPLIT THE DIFFERENCE BETWEEN THE TWO EXTREMES AND CALL FOR A SLOW
NORTHWESTWARD MOTION AFTER 72 HR.  THIS IS A LOW-CONFIDENCE TRACK
FORECAST.

THE DEPRESSION IS EXPERIENCING SOME SOUTHERLY SHEAR WHICH IS
PROBABLY SLOWING DEVELOPMENT.  THIS SHEAR WILL LIKELY LET UP IN
12-24 HR AND ALLOW THE DEPRESSION TO STRENGTHEN INTO A TROPICAL
STORM.  THE SHIPS MODEL AND THE SPREAD BETWEEN THE BAMS AND BAMD
SUGGEST THAT THE SHEAR WILL INCREASE AGAIN IN 48-72 HR...SO THE
INTENSITY FORECAST WILL CALL FOR A PEAK INTENSITY OF 60 KT AT THAT
TIME.  THE INTENSITY FORECAST IS IN BEST AGREEMENT WITH THE SHIPS
MODEL AND FAR ABOVE THE GFDL FORECAST.  THE GFS AND UKMET SUGGEST
THAT THE DEEP-LAYER TROUGH COULD COME CLOSE ENOUGH TO FEED COOLER
AIR INTO THE CYCLONE...AND SHOULD THAT HAPPEN IT COULD THROW A
MONKEY WRENCH INTO THE CYCLONE STRUCTURE AND THE INTENSITY
FORECAST.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/0300Z 27.4N  78.5W    30 KT
 12HR VT     07/1200Z 27.7N  78.8W    35 KT
 24HR VT     08/0000Z 28.1N  79.3W    40 KT
 36HR VT     08/1200Z 28.5N  79.7W    50 KT
 48HR VT     09/0000Z 28.8N  80.0W    60 KT
 72HR VT     10/0000Z 29.5N  80.5W    60 KT
 96HR VT     11/0000Z 30.5N  81.5W    50 KT...INLAND
120HR VT     12/0000Z 30.5N  82.5W    30 KT...INLAND
 
 
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