550 WTPZ43 KNHC 070234 TCDEP3 Tropical Storm Henriette Discussion Number 12 NWS National Hurricane Center Miami FL EP082025 500 PM HST Wed Aug 06 2025 Henriette’s satellite presentation has deteriorated since the previous advisory, with the cyclone now nearly devoid of all deep convection and the low-level center fully exposed. The most recent subjective Dvorak intensity estimates were 3.0/45 kt from TAFB, while SAB deemed the cyclone too weak to classify. Meanwhile, objective estimates from UW-CIMSS have ranged from 37 to 51 kt over the past several hours. An earlier 06/1755Z Metop-C ASCAT pass depicted numerous 40 kt wind barbs, with a single 40–45 kt wind barb noted north of the low-level center. Based on these data, the initial intensity for this advisory is maintained, at perhaps a generous, 45 kt. The cyclone is moving westward, or 275 degrees, at 14 kt. This general motion is expected to persist tonight and Thursday, as Henriette continues to be steered by a strengthening subtropical ridge to its north. A gradual turn toward the west-northwest and eventually northwest is expected to begin Friday and continue through the weekend, as an amplifying longwave trough northwest of Hawaii begins to erode the western extent of the subtropical ridge. The official track forecast remains closely aligned with the latest multi-model consensus aids and is largely unchanged from the previous advisory. There is high confidence that the center of Henriette will remain far to the north of the Hawaiian Islands. Henriette will be moving over gradually cooling sea surface temperatures, lowering to near 24C, while mid-level relative humidity also falls below 50 percent. Despite these marginal thermodynamic conditions, Henriette’s well-established circulation is likely to remain resilient due to the low-shear environment the cyclone will be transiting through. As a result, only slight weakening is forecast during the next 12 hours or so, followed by little change in strength through 72 hours. If Henriette can survive the passage over the cooler waters, as has been advertised by the GFS and ECMWF models for several days now, re-intensification appears likely over the weekend and into early next week as sea surface temperatures warm to levels conducive for strengthening. The official intensity forecast reflects this, bringing Henriette to hurricane strength by 120 hours. The intensity forecast is mostly unchanged and remains closely aligned with the dynamical intensity guidance aid HCCA and the regional hurricane models. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 18.2N 132.4W 45 KT 50 MPH 12H 07/1200Z 18.3N 134.8W 40 KT 45 MPH 24H 08/0000Z 18.7N 137.9W 40 KT 45 MPH 36H 08/1200Z 19.2N 141.0W 40 KT 45 MPH 48H 09/0000Z 20.0N 143.8W 40 KT 45 MPH 60H 09/1200Z 21.1N 146.4W 40 KT 45 MPH 72H 10/0000Z 22.5N 149.0W 45 KT 50 MPH 96H 11/0000Z 25.5N 153.3W 55 KT 65 MPH 120H 12/0000Z 29.0N 157.5W 65 KT 75 MPH $$ Forecaster Jelsema (CPHC)
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