Tropical Depression NINE
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TROPICAL DEPRESSION NINE DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT THU AUG 21 2003
IR SATELLITE IMAGES SHOW LITTLE APPARENT CHANGE IN THE ORGANIZATION
OF THE DEPRESSION. DEEP CONVECTION HAS WANED OVER THE PAST SEVERAL
HOURS...HOWEVER THIS MAY BE A TEMPORARY FLUCTUATION SUCH AS
OCCURRED WEDNESDAY NIGHT. THERE IS A FAIRLY IMPRESSIVE UPPER-LEVEL
OUTFLOW PATTERN OVER THE SYSTEM AND VERTICAL SHEAR IS NOT EXPECTED
TO BECOME PROHIBITIVELY STRONG. THEREFORE THE INTENSITY FORECAST
SHOWS THE SYSTEM BECOMING A TROPICAL STORM TOMORROW. DURING THE
FORECAST PERIOD...THE INTENSIFICATION PROCESS SHOULD BE INTERRUPTED
BY INTERACTION WITH THE MOUNTAINOUS LAND MASSES OF HISPANIOLA AND
EASTERN CUBA.
THE INITIAL MOTION IS JUST SLIGHTLY SLOWER THAN BEFORE...AND LITTLE
CHANGE HAS BEEN MADE TO THE PREVIOUS OFFICIAL TRACK FORECAST.
STEERING CURRENTS ARE EXPECTED TO WEAKEN DURING THE NEXT COUPLE OF
DAYS...AND WITH THIS COMES GREATER UNCERTAINTY IN THE FORECAST
TRACK LATER IN THE PERIOD. TRACK GUIDANCE MODELS DIVERGE SOMEWHAT
BEYOND 48 HOURS. THE OFFICIAL FORECAST...LIKE THE PREVIOUS
ONE...LEANS TOWARD THE GFDL SOLUTION. HOWEVER IF THE CYCLONE
REMAINS WEAK...IT COULD TAKE A MORE SOUTHERN TRACK...SIMILAR TO
THAT SHOWN BY THE NOGAPS.
CAUTIONARY NOTE...ONE SHOULD KEEP IN MIND THAT THERE IS CONSIDERABLE
UNCERTAINTY IN NOT ONLY THE 4- AND 5-DAY FORECAST POSTIONS...BUT
ALSO IN THE INTENSITY AT THESE EXTENDED RANGES.
FORECASTER PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 22/0300Z 15.4N 67.0W 30 KT
12HR VT 22/1200Z 16.1N 68.5W 35 KT
24HR VT 23/0000Z 17.2N 70.6W 40 KT
36HR VT 23/1200Z 18.4N 72.4W 45 KT
48HR VT 24/0000Z 19.5N 74.0W 50 KT
72HR VT 25/0000Z 21.5N 76.5W 50 KT
96HR VT 26/0000Z 23.5N 78.0W 55 KT
120HR VT 27/0000Z 25.5N 79.5W 60 KT
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