Tropical Depression EIGHT-E

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TROPICAL DEPRESSION EIGHT-E DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT SAT AUG 09 2003
 
TROPICAL DEPRESSION EIGHT-E HAS CONTINUED TO BECOME BETTER ORGANIZED
DURING THE PAST 6 HOURS WITH A LARGE BURST OF COLD CONVECTION
HAVING DEVELOPED NORTHWEST OF THE ALLEGED LOW-LEVEL CENTER
POSITION. THE OUTFLOW PATTERN HAS ALSO IMPROVED SIGNIFICANTLY...
ESPECIALLY IN THE WESTERN SEMICIRCLE. THE INITIAL INTENSITY IS
INCREASED TO 30 KT BASED ON CONSENSUS 30 KT...OR T2.0...INTENSITY
ESTIMATES FROM ALL THREE SATELLITE AGENCIES.
 
THE INITIAL MOTION ESTIMATE IS 275/15. THE FORWARD MOTION AND
INITIAL POSITION ESTIMATES ARE SOMEWHAT UNCERTAIN. CONVENTIONAL
INFRARED SATELLITE FIX POSITIONS ARE SCATTERED ABOUT THE COMPASS...
WHICH LENDS TO THE UNCERTAINTY IN THE INITIAL POSITION. WHILE THE
INITIAL POSITION WAS ADJUSTED SLIGHTLY NORTHWARD FROM THE PREVIOUS
ADVISORY BASED ON A WEAK SIGNATURE IN AN EARLIER SSMI OVERPASS...
THE POSITION WAS NOT TAKEN AS FAR NORTH OR WEST AS SOME OF THE
SATELLITE POSITION ESTIMATES SUGGEST. TD-8E IS EXPECTED TO REMAIN
ON THE SOUTH SIDE OF A STRONG SUBTROPICAL RIDGE AND...THEREFORE...
SHOULD BE STEERED MAINLY WESTWARD. THE FORWARD SPEED WAS INCREASED
THROUGHOUT THE FORECAST PERIOD BASED ON THE ASSUMPTION THAT THE
LARGE CIRCULATION WILL ADD SOME BETA-EFFECT MOTION TO THE MEAN
STEERING FLOW. THE OFFICIAL FORECAST TRACK IS A LITTLE NORTH OF AND
FASTER THAN THE PREVIOUS TRACK AND IS VERY CLOSE TO THE GFDL...GFS
...GFS ENSEMBLE MEAN...AND THE THREE BETA-ADVECTION MODELS. IT
SHOULD BE NOTED THAT THE 09/06Z NOGAPS AND 09/00Z UKMET MODEL RUNS
DISSIPATE THE CYCLONE IN 24 HOURS OR LESS...WHICH SEEMS UNLIKELY.
 
WHILE THE INITIAL POSITION ESTIMATE IS NOT LOCATED IN THE CENTER OF
THE DEEP CONVECTION...THE CYCLONE STILL HAS GOOD STRUCTURE AND AN
IMPRESSIVE MID-LEVEL CIRCULATION. IT IS QUITE POSSIBLE THAT THE
LOW-LEVEL CENTER WILL REDEVELOP FARTHER WEST AND CLOSER TO THE
STRONGEST CONVECTION AND BECOME A TROPICAL STORM BY THE NEXT
ADVISORY. THE SHIPS INTENSITY MODEL BRINGS THE CYCLONE UP TO 67 KT
BY 72 HOURS...WHILE THE GFDL KILLS THE SYSTEM BY 48 HOURS. GIVEN
THE RATHER IMPRESSIVE CONVECTIVE AND OUTFLOW PATTERN...MY FEELING
IS THAT EVEN THE SHIPS MODEL COULD BE TOO LOW AND TOO SLOW WITH THE
INTENSIFICATION TREND. THE OFFICIAL FORECAST IS FOR THE CYCLONE TO
BECOME A HURRICANE BY 48 HOURS AND THEN REMAIN STEADY FOR ABOUT 36
HOURS WITH ONLY SLOW WEAKENING AFTER THAT AS THE SYSTEM MOVES NEAR
COOLER WATER. HOWEVER...IF THE LOW-LEVEL CENTER BECOMES EMBEDDED
WITHIN THE DEEP CONVECTION DURING THE NEXT 6 HOURS...THEN THE
INTENSITY FORECAST WILL LIKELY HAVE TO BE INCREASED EVEN MORE.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/1500Z 13.8N 113.3W    30 KT
 12HR VT     10/0000Z 14.2N 115.5W    40 KT
 24HR VT     10/1200Z 14.8N 118.3W    50 KT
 36HR VT     11/0000Z 15.3N 121.2W    60 KT
 48HR VT     11/1200Z 15.6N 124.1W    65 KT
 72HR VT     12/1200Z 16.0N 129.0W    65 KT
 96HR VT     13/1200Z 16.5N 134.0W    60 KT
120HR VT     14/1200Z 17.0N 139.0W    55 KT
 
 
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