Issued at 500 AM HST Wed Aug 06 2025
546 WTPZ43 KNHC 061457 TCDEP3 Tropical Storm Henriette Discussion Number 10 NWS National Hurricane Center Miami FL EP082025 500 AM HST Wed Aug 06 2025 Henriette has changed very little this morning. It continues to produce a relatively small area of deep convection, with cold cloud tops present mostly to the north of its low-level center. The initial intensity remains 45 kt for this advisory, based on overnight ASCAT data and the lack of noticeable change in Henriette's structure since that time. Virtually no change was made to the NHC track forecast. Henriette is moving westward to west-northwestward to the south of a deep ridge centered over the northern east Pacific. In a few days, a trough approaching from the west will turn Henriette toward the northwest, taking the tropical cyclone north of Hawaii. The various deterministic and global ensemble models are all in good agreement on the forecast, so confidence in the track forecast is fairly high. The tropical storm is still forecast to slowly weaken during the next few days while it moves over cool SSTs near 24C. However, once Henriette moves north of Hawaii, it will move over warmer waters. Upper-level difluent flow associated with a mid-latitude trough to the northwest may also provide additional support for intensification. As a result, most of the dynamical models forecast strengthening to occur near the end of the forecast period, and the NHC intensity forecast has been adjusted upward accordingly. Some of the guidance is much higher, including both HAFS models, which show Henriette developing a robust inner core by 120 h. Additional adjustments to the intensity forecast at day 4 or 5 may be needed with future advisories. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 18.1N 129.7W 45 KT 50 MPH 12H 07/0000Z 18.3N 132.0W 45 KT 50 MPH 24H 07/1200Z 18.6N 135.0W 40 KT 45 MPH 36H 08/0000Z 19.0N 138.0W 40 KT 45 MPH 48H 08/1200Z 19.6N 141.1W 40 KT 45 MPH 60H 09/0000Z 20.4N 144.0W 40 KT 45 MPH 72H 09/1200Z 21.5N 146.6W 40 KT 45 MPH 96H 10/1200Z 24.2N 151.3W 45 KT 50 MPH 120H 11/1200Z 27.5N 155.0W 60 KT 70 MPH $$ Forecaster D. Zelinsky
