ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
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
NNNN
Problems?