Tropical Storm HILDA

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TROPICAL DEPRESSION HILDA DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT TUE AUG 12 2003

THE FULLY EXPOSED LOW-LEVEL CENTER OF HILDA HAS TURNED WESTWARD
DURING THE PAST 6 HOURS AND IS FARTHER SOUTH THAN THE PREVIOUS
ADVISORY POSITION. THERE ARE ONLY A FEW PUFFS OF WEAK CONVECTION
NEAR THE CENTER...BUT A BAND OF DEEP CONVECTION HAS REDEVELOPED
WITHIN 75 NMI OF THE CENTER IN THE NORTHEAST QUADRANT. THE INITIAL
INTENSITY IS MAINTAINED AT 25 KT BASED ON THE RECENT CONVECTIVE
BANDING THAT HAS FORMED AND A DVORAK INTENSITY OF 25 KT FROM TAFB.
 
THE INITIAL MOTION ESTIMATE IS 270/09...BASED ON THE LAST 5 HOURS
THAT THE EXPOSED LOW-LEVEL CENTER HAS BEEN CLEARLY VISIBLE. HILDA
IS EXPECTED REMAIN UNDER THE INFLUENCE OF A STRONG SUBTROPICAL
RIDGE TO THE NORTH AND BE STEERED WESTWARD BY THE LOW-LEVEL
EASTERLIES. THE OFFICIAL FORECAST TRACK IS SOUTH OF AND SLOWER THAN
THE PREVIOUS FORECAST TRACK...AND IS CLOSE TO THE CONSENSUS OF THE
GUNS AND GUNA MODELS.

THE SOUTHERLY INFLOW REMAINS CUTOFF BY THE ITCZ TO THE SOUTH OF
HILDA...AND ONLY INTERMITTENT BURSTS OF CONVECTION WILL KEEP THE
CYCLONE ALIVE FOR THE NEXT 12 TO 24 HOURS. BY 24 HOURS...HOWEVER
...HILDA IS EXPECTED TO MOVE INTO A THICK FIELD OF COLD AIR
STRATOCUMULUS CLOUDS THAT BEGINS NEAR 133W LONGITUDE...AND THAT IS
THE TIMING USED FOR THE BEGINNING OF DISSIPATION IN THE OFFICIAL
FORECAST. THIS SCENARIO IS SIMILAR TO THE SHIPS INTENSITY MODEL...
WHICH ALSO INCREASES THE WESTERLY SHEAR TO NEAR 40 KT BY 36 HOURS
AND DISSIPATES THE CYCLONE BY THAT TIME.

FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/0300Z 18.4N 129.7W    25 KT
 12HR VT     13/1200Z 18.6N 131.1W    25 KT
 24HR VT     14/0000Z 18.8N 133.0W    20 KT...DISSIPATING
 36HR VT     14/1200Z 18.9N 135.1W    20 KT...REMNANT LOW
 48HR VT     15/0000Z 18.9N 137.4W    20 KT...REMNANT LOW
 72HR VT     16/0000Z...DISSIPATED
 
 
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