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TROPICAL STORM HENRIETTE DISCUSSION NUMBER   8
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT THU SEP 06 2001
 
HENRIETTE HAS CONTINUED TO BECOME BETTER ORGANIZED AND A 06/0531Z 
SSMI OVERPASS INDICATED A PARTIAL EYEWALL WAS DEVELOPING.  THE 
INITIAL INTENSITY OF 50 KT IS BASED ON SATELLITE INTENSITY ESTIMATES 
OF 55 KT FROM TAFB AND 45 KT FROM SAB.  UPPER-LEVEL OUTFLOW IS GOOD 
TO THE SOUTH...BUT IS ONLY FAIR ELSEWHERE OWING TO MODERATE 
UPPER-LEVEL EASTERLY FLOW IMPINGING ON THE CYCLONE.
 
THE INITIAL MOTION ESTIMATE IS 285/13. THERE IS LIKELY SOME BINARY 
INTERACTION OCCURRING WITH HURRICANE GIL...WHICH IS LOCATED ABOUT 
480 NM WEST-SOUTHWEST OF HENRIETTE.  HOWEVER...THE DOMINANT STEERING 
FLOW SHOULD COME FROM THE MID- TO UPPER-LEVEL RIDGE SITUATED TO THE 
NORTH OF BOTH HENRIETTE AND GIL.  SURFACE ANALYSES INDICATE THAT GIL 
AND HENRIETTE ARE BOTH EMBEDDED WITHIN A LARGER-SCALE GYRE.  THE 
ENTIRE ENVELOPE SHOULD SHIFT WESTWARD DUE TO THE DEEP EASTERLY FLOW 
ON THE SOUTHERN SIDE OF THE LARGE EAST-WEST ORIENTED SUBTROPICAL 
RIDGE.  THE GLOBAL MODELS ARE HAVING A DIFFICULT TIME KEEPING THE 
TWO TROPICAL CYCLONES AS SEPARATE ENTITIES. THE AVN WEAKENS 
HENRIETTE AND MERGES THE IT WITH GIL IN ABOUT 36 TO 48 HOURS...WHILE 
THE UKMET ALSO WEAKENS HENRIETTE AND SHEARS IT OUT INTO A BAND ON 
THE NORTH SIDE OF GIL IN ABOUT THE SAME TIME PERIOD.  GIVEN THE 
RATHER IMPRESSIVE CONVECTIVE CLOUD SHIELD AND OVERALL ORGANIZATION 
OF HENRIETTE...THE AVN AND UKMET MODEL SOLUTIONS APPEAR UNLIKELY. 
THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS FORECAST TRACK AND 
CLOSE TO THE SHALLOW AND MEDIUM BAM MODELS...AND BETWEEN THE GFDL 
AND GFDN MODELS.

SLOW INTENSIFICATION IS EXPECTED FOR THE NEXT 24 TO 36 HOURS...AFTER 
WHICH HENRIETTE WILL BE MOVING OVER COLDER WATER.  IT IS POSSIBLE 
THAT HENRIETTE COULD REACH MINIMAL HURRICANE INTENSITY IN THE NEXT 
12 TO 24 HOURS BEFORE LEVELING OFF AND THEN SLOWLY WEAKENING OVER 
SUB-26C SSTS.  THE MODERATE UPPER-LEVEL EASTERLY FLOW IS RESTRICTING 
OUTFLOW TO THE EAST AND INHIBITING INTENSIFICATION SLIGHTLY.  
HOWEVER... THE MAIN EFFECT OF THIS FLOW PATTERN HAS BEEN TO KEEP 
HENRIETTE MOVING IN A GENERAL WEST TO WEST-NORTHWEST DIRECTION.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     06/0900Z 18.3N 119.1W    50 KTS
12HR VT     06/1800Z 19.1N 121.0W    55 KTS
24HR VT     07/0600Z 20.2N 123.5W    60 KTS
36HR VT     07/1800Z 21.1N 125.7W    55 KTS
48HR VT     08/0600Z 21.9N 128.2W    40 KTS
72HR VT     09/0600Z 23.0N 134.0W    25 KTS...DISSIPATING
 
 
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