297 WTPA43 PHFO 082033 TCDCP3 Post-Tropical Cyclone Henriette Discussion Number 19 NWS Central Pacific Hurricane Center Honolulu HI EP082025 Issued by NWS National Hurricane Center Miami FL 1100 AM HST Fri Aug 08 2025 Approximately 18 hours have passed since Henriette last produced any significant areas of deep convection, and the cyclone has now been downgraded to a post-tropical remnant low. The current motion is now west-northwestward, or 285/15 kt. There are no changes to the track forecast philosophy. Henriette will move west-northwestward along the southwestern periphery of a subtropical ridge to its northeast. A turn toward the northwest is forecast late this weekend into early next week as Henriette becomes steered between an amplifying longwave trough northwest of Hawaii and the subtropical ridge to its northeast. No significant changes were made to the NHC track forecast, which is near the middle of the guidance envelope. Confidence remains high that Henriette will remain far to the north of Hawaii. The cyclone is currently over 24C sea-surface temperatures (SSTs) and located within a very dry environment. Over the next couple of days, Henriette will enter an area of gradually increasing SSTs. At the same time, an approaching longwave trough will bring colder temperatures aloft near Henriette, which will increase the instability. The majority of the model guidance indicates this will be enough to reignite convection and cause Henriette to restrengthen to a tropical storm. The peak intensity forecast in about 72 hours has been lowered slightly from the previous NHC forecast, and now lies between the middle and upper end of the guidance. Beyond day 4, wind shear from the longwave trough and cooling SSTs should lead to steady weakening as Henriette moves farther into the mid-latitudes. Given the high likelihood of regeneration back into a tropical cyclone and subsequent restrengthening, NHC will be maintaining advisories during the post-tropical phase. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 19.9N 143.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 12H 09/0600Z 20.7N 145.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 09/1800Z 21.9N 147.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 10/0600Z 23.3N 149.8W 40 KT 45 MPH...TROPICAL CYCLONE 48H 10/1800Z 25.0N 152.0W 50 KT 60 MPH 60H 11/0600Z 26.9N 154.3W 55 KT 65 MPH 72H 11/1800Z 29.1N 156.9W 60 KT 70 MPH 96H 12/1800Z 33.5N 161.5W 55 KT 65 MPH 120H 13/1800Z 39.0N 165.9W 45 KT 50 MPH $$ Forecaster Hagen
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