Tropical Storm Henriette Forecast Discussion Number 8
Issued at 500 PM HST Tue Aug 05 2025
565 WTPZ43 KNHC 060244 TCDEP3 Tropical Storm Henriette Discussion Number 8 NWS National Hurricane Center Miami FL EP082025 500 PM HST Tue Aug 05 2025 The satellite presentation of Henriette had remained rather ragged for several hours since the previous advisory, however, a new burst of deep convection has now developed just to the west of the low-level center of the cyclone. The latest subjective Dvorak current intensity estimates from TAFB and SAB were 3.0/45 kt and 2.5/35 kt respectively. Meanwhile, the objective estimates from UW-CIMSS have ranged from 34 to 47 kt during the past several hours. Earlier today, a 05/1815Z Metop-C ASCAT pass showed several 45 knot wind barbs to the north of the low level center and a 05/2133Z AMRS2 pass revealed a nice inner core structure of the cyclone. Based on these data, the initial intensity for this advisory has been held at 45 kt. The cyclone is moving west-northwest, or 290 degrees, at 14 kt. A slight turn toward the west is expected tonight, with this motion then continuing for the next several days as Henriette is steered by a strengthening subtropical ridge to the north. By 72 hours, a turn toward the west-northwest is anticipated as an amplifying longwave trough northwest of Hawaii erodes the western extent of the subtropical ridge steering the cyclone. The official track forecast closely follows a blend of the latest consensus guidance, and is very close to the previous advisory. Henriette will remain in a low shear environment during the next several days, while sea surface temperatures gradually cool to near or slightly below 24C and the mid-level moisture decreases below 50 percent. Despite the cooling water and drying mid-levels, the large circulation of the system and the well-established inner core should keep Henriette rather resilient in the very low shear environment during the next several days. The intensity forecast only calls for slight weakening during this time followed by little change in strength. By late in the forecast period, sea surface temperatures will begin to increase, and if the cyclone manages to survive the trip over the cooler water as suggested by the GFS and ECMWF models, some re-intensification is possible and the official forecast reflects this. The intensity forecast is near the middle of the intensity guidance envelope and most closely aligned with the IVCN intensity aid. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 17.6N 126.9W 45 KT 50 MPH 12H 06/1200Z 17.9N 129.1W 45 KT 50 MPH 24H 07/0000Z 18.3N 132.1W 45 KT 50 MPH 36H 07/1200Z 18.6N 135.1W 40 KT 45 MPH 48H 08/0000Z 19.0N 138.1W 40 KT 45 MPH 60H 08/1200Z 19.6N 141.0W 40 KT 45 MPH 72H 09/0000Z 20.5N 143.8W 40 KT 45 MPH 96H 10/0000Z 22.8N 148.9W 40 KT 45 MPH 120H 11/0000Z 25.1N 153.2W 45 KT 50 MPH $$ Forecaster Jelsema (CPHC)
