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Hurricane HENRIETTE (Text)

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HURRICANE HENRIETTE DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP082013
200 PM PDT WED AUG 07 2013

THE CLOUD PATTERN OF HENRIETTE HAS CHANGED A LITTLE DURING THE PAST
6 HOURS.  AN EYE IS TRYING TO APPEAR IN THE MIDDLE OF THE CENTRAL
DENSE OVERCAST...WHILE AN APPARENT DRY SLOT IS WRAPPING BETWEEN THE
CDO AND THE OUTER BANDING IN THE EASTERN SEMICIRCLE.  SATELLITE
INTENSITY ESTIMATES REMAIN 77 KT FROM TAFB AND SAB...AND THERE WAS
A 70 KT AMSU INTENSITY ESTIMATE FROM CIMSS A FEW HOURS AGO.  BASED
ON THESE DATA...THE INITIAL INTENSITY REMAINS 75 KT.

THE INITIAL MOTION IS 300/10.  THE HURRICANE IS CURRENTLY MOVING
TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE.  HOWEVER...THE
DYNAMICAL MODELS FORECAST TO RIDGE TO BUILD TO THE NORTHWEST OF THE
CYCLONE AFTER 24-36 HOURS.  THIS SHOULD CAUSE THE SYSTEM TO TURN
TOWARD THE WEST AND WEST-SOUTHWEST.  THE TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH THIS SCENARIO...AND THE GUIDANCE HAS CHANGED LITTLE
SINCE THE LAST ADVISORY.  THE NEW FORECAST TRACK IS AN UPDATE OF
THE OLD TRACK AND LIES NEAR THE CENTER OF THE TRACK GUIDANCE
ENVELOPE.

HENRIETTE IS EXPECTED TO MOVE OVER COLDER WATERS AND INTO SOMEWHAT
STRONGER WESTERLY VERTICAL WIND SHEAR DURING THE NEXT 12-48 HOURS. 
THIS SHOULD CAUSE THE SYSTEM TO WEAKEN...WITH THE GFS...THE
UKMET...AND THE CANADIAN MODELS FORECASTING THE MID/UPPER-LEVEL
PART OF THE CIRCULATION TO DISSIPATE DURING THIS TIME.  THE NEW
INTENSITY FORECAST CALLS FOR A SLIGHTLY FASTER WEAKENING THAN THE
PREVIOUS FORECAST.  AFTER 48 HOURS...THE SYSTEM IS EXPECTED TO MOVE
OVER WARMER SEA SURFACE TEMPERATURES AND DECREASED SHEAR. 
HOWEVER...THE INTENSITY GUIDANCE CALLS FOR CONTINUED WEAKENING
AFTER 48 HOURS...APPARENTLY DUE TO INCREASED DRY AIR ENTRAINMENT. 
THE LATTER PART OF THE INTENSITY FORECAST FOLLOWS THE MODEL
TREND...BUT WITH A SLOWER WEAKENING RATE THAN THE PREVIOUS
ADVISORY.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/2100Z 16.7N 135.8W   75 KT  85 MPH
 12H  08/0600Z 17.3N 137.2W   70 KT  80 MPH
 24H  08/1800Z 17.7N 138.8W   60 KT  70 MPH
 36H  09/0600Z 17.6N 140.6W   50 KT  60 MPH
 48H  09/1800Z 17.1N 142.7W   45 KT  50 MPH
 72H  10/1800Z 16.0N 148.0W   35 KT  40 MPH
 96H  11/1800Z 14.5N 154.5W   30 KT  35 MPH
120H  12/1800Z 13.0N 160.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER BEVEN
 
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