672 WTPA43 PHFO 100232 TCDCP3 Tropical Storm Henriette Discussion Number 24 NWS Central Pacific Hurricane Center Honolulu HI EP082025 Issued by NWS National Hurricane Center Miami FL 500 PM HST Sat Aug 09 2025 Satellite imagery shows that Henriette's curved band of convection on the west side of the circulation has fragmented with warming tops in recent hours, though some redevelopment has begun near and northwest of the center more recently. An AMSR2 pass at 2130 UTC confirmed a well-organized low-level structure, and a 2012 UTC ASCAT-C pass showed peak winds of about 35 kt, consistent with objective estimates from UW-CIMSS. The initial intensity is held at 35 kt for this advisory. The initial motion is northwest at 12 kt, steered by a subtropical ridge to the northeast and an amplifying mid-latitude trough to the northwest. This motion should persist through early next week, keeping Henriette well northeast of the Hawaiian Islands. Guidance indicates the sharp upper trough will cut off into an upper low on Monday and retrograde westward, a pattern that should maintain Henriette’s northwestward motion. The updated forecast is very similar to the previous one and lies near the middle of the tightly clustered consensus aids. Sea-surface temperatures along the forecast track should gradually warm from near 25 C to around 26–27 C through 60 h. Despite the presence of dry mid- to upper-level air, a combination of warmer waters and increasing upper-level divergence associated with an upper trough to the northwest should enhance outflow and support gradual strengthening. The NHC forecast continues to show a peak near 55 kt in the 48–60 h period, nearly identical to the previous forecast and near the middle of the guidance envelope. Thereafter, cooler waters, increasing shear, and diminishing upper-level outflow should result in steady weakening, with Henriette expected to become a post-tropical remnant low by 96 h and dissipate by 120 h as it is absorbed into the mid-latitude flow. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 23.0N 149.1W 35 KT 40 MPH 12H 10/1200Z 24.2N 150.7W 40 KT 45 MPH 24H 11/0000Z 26.2N 152.9W 45 KT 50 MPH 36H 11/1200Z 28.3N 155.4W 50 KT 60 MPH 48H 12/0000Z 30.5N 158.1W 55 KT 65 MPH 60H 12/1200Z 32.7N 160.6W 55 KT 65 MPH 72H 13/0000Z 34.9N 163.0W 50 KT 60 MPH 96H 14/0000Z 38.8N 166.9W 35 KT 40 MPH...POST-TROPICAL 120H 15/0000Z...DISSIPATED $$ Forecaster Gibbs (CPHC)
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