055
WTPZ43 KNHC 072120
TCDEP3
TROPICAL STORM HENRIETTE DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082025
1100 AM HST THU AUG 07 2025
HENRIETTE HAS BEEN PRODUCING A SMALLER AREA OF DEEP CONVECTION THAN
EARLIER, AS IT SEEMS TO BE STRUGGLING A BIT WITH DRY AIR AND
SEA-SURFACE TEMPERATURES NEAR 24 C. THE LATEST SUBJECTIVE DVORAK
CURRENT INTENSITY ESTIMATES ARE 2.5/35 KT FROM TAFB AND 1.5/25 KT
FROM SAB. THE LATEST OBJECTIVE ESTIMATES FROM UW-CIMMS RANGE FROM
ABOUT 30 TO 40 KT. A RECENT 1914 UTC ASCAT-C PASS SUGGESTS THAT
HENRIETTE HAS LIKELY WEAKENED A BIT FROM EARLIER. BASED ON THE
ABOVE DATA, THE INITIAL INTENSITY IS LOWERED TO 40 KT FOR THIS
ADVISORY.
THE MOTION OF 280/14 KT IS UNCHANGED FROM THE PREVIOUS ADVISORY.
THIS MOTION WILL CONTINUE THROUGH TODAY AS HENRIETTE IS STEERED BY
MID-LEVEL RIDGING WELL TO ITS NORTH. THE CYCLONE WILL THEN ROUND
THE SOUTHWESTERN PERIPHERY OF THE MID-LEVEL RIDGE AS A LARGE
DEEP-LAYER TROUGH APPROACHES FROM THE WEST. THESE FEATURES WILL
CAUSE HENRIETTE TO GRADUALLY TURN TOWARD THE NORTHWEST IN A COUPLE
OF DAYS. VERY LITTLE CHANGE HAS BEEN MADE TO THE NHC TRACK
FORECAST, WHICH LIES NEAR THE TIGHTLY CLUSTERED CONSENSUS AIDS.
CONFIDENCE IN THE TRACK FORECAST IS HIGH THROUGH THE WEEKEND, AND
HENRIETTE WILL NOT DIRECTLY IMPACT THE HAWAIIAN ISLANDS.
HENRIETTE IS EXPECTED TO CONTINUE MOVING OVER COOL OCEAN WATERS NEAR
24C FOR ANOTHER 36 H BEFORE IT BEGINS TO GRADUALLY MOVE OVER
INCREASING WATER TEMPERATURES. THE TROPICAL STORM WILL ALSO
CONTINUE MOVING THROUGH A VERY DRY ENVIRONMENT. MOST OF THE
GUIDANCE SHOWS THE STORM MAINTAINING A 35-40 KT INTENSITY DURING
THIS TIME. HENRIETTE IS ALSO EXPECTED TO ENCOUNTER COLDER THAN
NORMAL MID- AND UPPER-LEVEL TEMPERATURES IN A COUPLE OF DAYS. IF
HENRIETTE SURVIVES THE NEXT 48 H OR SO, THEN STRENGTHENING WOULD
APPEAR LIKELY LATER IN THE FORECAST PERIOD DUE TO INCREASING
SEA-SURFACE TEMPERATURES, VERY LOW VERTICAL WIND SHEAR, AND
DECREASING MID- TO UPPER-LEVEL TEMPERATURES AS THE AFOREMENTIONED
DEEP-LAYER TROUGH APPROACHES. THE OFFICIAL FORECAST SHOWS SOME
SLIGHT WEAKENING IN THE SHORT TERM, FOLLOWED BY STRENGTHENING TO A
HURRICANE BY DAY 4 WELL TO THE NORTH OF HAWAII. THE LATEST NHC
FORECAST IS NEAR THE INTENSITY CONSENSUS AND CLOSE TO THE HIGHER END
OF THE GUIDANCE AT DAY 4 AND 5. IT SHOULD BE NOTED THAT THE HAFS
MODELS ARE SHOWING A SLIGHTLY HIGHER INTENSITY THAN THE NHC
FORECAST.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 18.9N 136.8W 40 KT 45 MPH
12H 08/0600Z 19.3N 139.2W 40 KT 45 MPH
24H 08/1800Z 19.9N 142.2W 40 KT 45 MPH
36H 09/0600Z 20.9N 145.0W 40 KT 45 MPH
48H 09/1800Z 22.1N 147.5W 40 KT 45 MPH
60H 10/0600Z 23.5N 150.0W 45 KT 50 MPH
72H 10/1800Z 25.2N 152.3W 55 KT 65 MPH
96H 11/1800Z 28.9N 156.7W 70 KT 80 MPH
120H 12/1800Z 32.6N 160.6W 65 KT 75 MPH
FORECASTER HAGEN
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