Tropical Storm HENRI

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TROPICAL DEPRESSION HENRI DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SAT SEP 06 2003
 
AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT IS CURRENTLY
INVESTIGATING HENRI...AND SO FAR THEY HAVE NOT FOUND MUCH IN THE
WAY OF WIND.  PEAK FLIGHT-LEVEL WINDS WERE 30 KT...BUT THE AIRCRAFT
HAS NOT SAMPLED THE CONVECTION NORTH OF THE CENTER YET.  THE 30 KT
ADVISORY WIND SPEED COULD BE A LITTLE HIGH.

THERE HAS BEEN LITTLE CHANGE TO THE FORECAST PHILOSOPHY THIS
AFTERNOON.  HENRI IS CURRENTLY EMBEDDED IN A SMALL AREA OF
RELATIVELY UNIFORM AND BRISK SOUTHWESTERLY FLOW BETWEEN A
DEEP-LAYER ANTICYCLONE OVER CENTRAL CUBA AND THE MID-LEVEL TROUGH
IN THE SOUTHEASTERN UNITED STATES.  THIS ENHANCED SYNOPTIC GRADIENT
WEAKENS TO THE EAST SO THE CURRENT RAPID INITIAL MOTION...
060/16...SHOULD BEGIN TO SLOW WITHIN THE NEXT 6-12 HOURS. THE
OFFICIAL FORECAST CALLS FOR A GRADUAL SLOWING OF THE MOTION OVER
THE NEXT THREE DAYS AS HIGH PRESSURE BUILDS TO THE NORTH OF HENRI.
 
HENRI WILL HAVE A BRIEF OPPORTUNITY TO STRENGTHEN SOME NOW THAT THE
CENTER HAS EMERGED INTO THE ATLANTIC.  THE SHIPS MODEL GUIDANCE
BRINGS HENRI UP TO 50 KT IN 48 HOURS.  THIS SEEMS EXCESSIVE GIVEN
THE MODEL-DIAGNOSED SHEAR OF 25 KT.  THE OFFICIAL FORECAST CALLS
FOR SOME STRENGTHENING BUT NOT AS MUCH AS THE SHIPS GUIDANCE. 
AFTER 36 HOURS...AS THE HIGH BUILDS NORTH OF HENRI AND THE LOW
LEVEL SYNOPTIC FLOW REVERSES...THE SHEAR IS AGAIN EXPECTED TO
INCREASE AND WEAKEN THE CYCLONE. IN THIS ENVIRONMENT...THE
CIRCULATION SHOULD GRADUALLY ELONGATE AND BECOME LOST WITHIN THE
FRONTAL ZONE CURRENTLY NORTH OF THE TROPICAL CYCLONE. 
 
FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      06/2100Z 29.4N  79.7W    30 KT
 12HR VT     07/0600Z 30.4N  78.1W    35 KT
 24HR VT     07/1800Z 31.3N  76.6W    40 KT
 36HR VT     08/0600Z 32.0N  75.2W    40 KT
 48HR VT     08/1800Z 32.5N  74.0W    35 KT...BECOMING EXTRATROPICAL
 72HR VT     09/1800Z 34.0N  71.0W    35 KT...EXTRATROPICAL
 96HR VT     10/1800Z...ABSORBED WITHIN FRONTAL ZONE
 
 
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