316
WTPA43 PHFO 130239
TCDCP3
TROPICAL STORM HENRIETTE DISCUSSION NUMBER 36
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP082025
ISSUED BY NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM HST TUE AUG 12 2025
HENRIETTE IS UNRAVELING QUICKLY. SINCE THE PRIOR ADVISORY, ITS
LOW-LEVEL CIRCULATION HAS BECOME DECOUPLED NORTHWEST FROM THE
REMAINING DEEP CONVECTION THAT IS DECREASING IN COVERAGE AND
INTENSITY. AN EARLIER SCATTEROMETER PASS HAD A PEAK WIND OF 47 KT,
BUT ITS LIKELY HENRIETTE HAS BEEN WEAKENING SINCE THAT TIME.
SUBJECTIVE DVORAK ESTIMATES ARE DECREASING AS FAST AS THEY ARE
ALLOWED, AND THE INITIAL INTENSITY THIS ADVISORY HAS BEEN DECREASED
TO 45 KT, CLOSE TO THE MOST RECENT SATCON VALUE.
HENRIETTE CONTINUES TO MOVE RAPIDLY TO THE NORTHWEST, ESTIMATED AT
315/16 KT. THIS GENERAL MOTION SHOULD CONTINUE FOR ANOTHER 12-24 H,
THOUGH NOW THAT THE CIRCULATION HAS BECOME MORE SHALLOW, IT IS
EXPECTED TO NOW TURN NORTHWARD AND THEN EASTWARD AROUND A LARGE
LOW-LEVEL SUBTROPICAL RIDGE UNTIL IT DISSIPATES. VERTICAL WIND
SHEAR DIAGNOSED BY SHIPS GUIDANCE IS ALREADY NEAR 20 KT IN THE
DIRECTION OF VERY DRY MID-LEVEL AIR. THIS SHEAR INCREASES FURTHER
FROM HERE ON OUT, AND BOTH THE GLOBAL AND REGIONAL-HURRICANE MODELS
SHOW DEEP CONVECTION NOT RETURNING OVER THE SMALL LOW-LEVEL VORTEX
AS IT ALSO MOVES OVER COOLING SEA-SURFACE TEMPERATURES. THUS, THE
LATEST NHC FORECAST WILL SHOW HENRIETTE BECOMING POST-TROPICAL IN
12 H, AND DISSIPATING ENTIRELY BY 72 H, WITH ITS FINAL RESTING
PLACE NEAR THE CENTER OF THE NORTH-CENTRAL PACIFIC SUBTROPICAL
RIDGE. THE NHC TRACK FORECAST IS ROUGHLY IN THE MIDDLE OF THE TRACK
GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 13/0300Z 35.3N 164.3W 45 KT 50 MPH
12H 13/1200Z 37.1N 166.3W 35 KT 40 MPH...POST-TROPICAL
24H 14/0000Z 39.6N 168.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 14/1200Z 41.8N 169.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 15/0000Z 43.4N 168.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 15/1200Z 43.5N 166.5W 15 KT 15 MPH...POST-TROP/REMNT LOW
72H 16/0000Z...DISSIPATED
FORECASTER PAPIN
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