[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 061439
TCDAT4
TROPICAL DEPRESSION NINE DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT SAT AUG 06 2005

THERE HAS BEEN LITTLE CHANGE IN THE OVERALL STRUCTURE OF THE
DEPRESSION THIS MORNING...EXCEPT THAT MULTIPLE SWIRLS HAVE BEEN
APPARENT NEAR THE MEAN CIRCULATION CENTER.  THIS MORNING'S QUIKSCAT
PASS MISSED THE DEPRESSION.  THE ADVISORY INTENSITY WILL REMAIN 30
KT...IN ACCORD WITH THE PASS FROM LAST NIGHT.  CONVECTION NEAR THE
CENTER IS CURRENTLY VERY LIMITED DUE TO WESTERLY SHEAR...DRY
AIR...AND RELATIVELY COOL SSTS.  NONE OF THESE CONDITIONS ARE
EXPECTED TO CHANGE MUCH OVER THE NEXT DAY OR SO...HOWEVER...THE
DEPRESSION WILL BE MOVING OVER 28C WATER IN ABOUT 48 HOURS.  A
TRACK TO THE SOUTH OF THE OFFICIAL FORECAST WOULD ALSO KEEP THE
SYSTEM AWAY FROM THE WESTERLY SHEAR.  THE OFFICIAL FORECAST IS VERY
CLOSE TO THE SHIPS GUIDANCE...ALTHOUGH IT IS WORTH NOTING THAT THE
GFDL GRADUALLY FADES THIS SYSTEM AWAY.

THE INITIAL MOTION IS 285/10...A LITTLE SLOWER THAN BEFORE.  THE
TRACK FORECAST REMAINS PROBLEMATIC.  A WEAKNESS IN THE 500 MB RIDGE
ASSOCIATED WITH TROPICAL STORM HARVY SHOULD BE NORTH OF THE
DEPRESSION IN ABOUT 48 HOURS.  MUCH OF THE GUIDANCE...LED BY THE
NOGAPS...LIFTS THE DEPRESSION INTO THIS WEAKNESS.  THE GFS ACTUALLY
SPLITS THE DEPRESSION...TAKING A PIECE NORTHWARD INTO THE WEAKNESS
BUT ALSO CARRYING A WEAK WAVE WEST-NORTHWESTWARD.  IT IS HARD TO BE
CONFIDENT AT THIS POINT ABOUT THE LONG-RANGE TRACK FORECAST.  IN
THE INTEREST OF CONTINUITY THE OFFICIAL FORECAST IS CLOSE TO THE
PREVIOUS ADVISORY AND NEAR THE DYNAMICAL MODEL CONSENSUS.
HOWEVER...SATELLITE IMAGES OVER THE PAST HOUR OR SO ARE SUGGESTING
THAT THE CIRCULATION CENTER IS BECOMING BETTER DEFINED ABOUT 45 NMI
TO THE NORTH OF MY ADVISORY POSITION.  IF THIS TURNS OUT TO BE THE
DOMINANT CENTER...THEN A NORTHWARD ADJUSTMENT OF THE TRACK MAY BE
REQUIRED THIS AFTERNOON.


FORECASTER FRANKLIN


FORECAST POSITIONS AND MAX WINDS

INITIAL      06/1500Z 17.9N  42.3W    30 KT
 12HR VT     07/0000Z 18.3N  43.8W    30 KT
 24HR VT     07/1200Z 18.9N  46.0W    30 KT
 36HR VT     08/0000Z 19.4N  48.0W    30 KT
 48HR VT     08/1200Z 20.4N  50.0W    35 KT
 72HR VT     09/1200Z 22.0N  53.0W    40 KT
 96HR VT     10/1200Z 23.5N  56.0W    45 KT
120HR VT     11/1200Z 25.5N  59.0W    50 KT


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