Issued at 500 AM HST Tue Aug 05 2025
804 WTPZ43 KNHC 051438 TCDEP3 Tropical Storm Henriette Discussion Number 6 NWS National Hurricane Center Miami FL EP082025 500 AM HST Tue Aug 05 2025 Henriette's cloud pattern has deteriorated a bit overnight. Modest southeasterly shear, evidence of a slight southeast to northwest tilt with height in a 0638 UTC GPM microwave image, and an increasingly inhibiting thermodynamic environment continue to impede strengthening. Based on a compromise of the Dvorak intensity estimates from TAFB, SAB, and recent CIMSS SATCON objective intensity analysis of 46 kt, the initial intensity is held at 45 kt. Little change in strength is expected during the next few days due to the above mentioned adverse atmospheric conditions, and Henriette traversing slightly cooler oceanic temperatures. Only the HAFS-B hurricane model suggests an increase to 50 kt during the 24-36 hrs. Of course, a 5 kt increase isn't out of the question. Beyond day 3, toward the end of the week, the thermodynamic environment is expected to become even more stifling while Henriette moves over the subtropical central Pacific waters. Subsequently, gradual weakening is noted in the official forecast. The NHC intensity forecast is near the previous one and is hedged toward the IVCN intensity consensus, and is just above the Decay-SHIPS statistical aid. Henriette's initial motion is estimated to be west-northwestward, or 290/13 kt. A general west-northwestward or westward motion is expected through day 4 while a strong subtropical ridge remains to the north of the cyclone. Toward the end of the period, Henriette is forecast to gradually turn northwestward in response to an amplifying mid- to upper-tropospheric trough approaching the Hawaiian Islands from the central north Pacific. The track forecast is essentially an update from the previous advisory and lies between the HCCA corrected consensus model and the ECMWF control. Henriette's wind radii were adjusted based on a 0839 UTC Oceansat-3 Scatterometer overpass. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 16.4N 124.3W 45 KT 50 MPH 12H 06/0000Z 16.9N 126.3W 45 KT 50 MPH 24H 06/1200Z 17.5N 129.1W 45 KT 50 MPH 36H 07/0000Z 18.0N 132.0W 45 KT 50 MPH 48H 07/1200Z 18.4N 134.9W 45 KT 50 MPH 60H 08/0000Z 18.8N 137.9W 45 KT 50 MPH 72H 08/1200Z 19.3N 140.8W 40 KT 45 MPH 96H 09/1200Z 21.0N 146.1W 35 KT 40 MPH 120H 10/1200Z 23.4N 150.7W 35 KT 40 MPH $$ Forecaster Roberts
