Post-Tropical Cyclone Mario Discussion Number 18

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Post-Tropical Cyclone Mario Discussion Number 18 NWS National Hurricane Center Miami FL EP132025 800 PM PDT Tue Sep 16 2025 Mario has not produced any deep convection for more than 12 hours. The system is now over sea-surface temperatures of 23C and southwesterly wind shear is increasing. All guidance is in good agreement that the remnant low of Mario will continue to weaken and dissipate on Thursday. The remnant low of Mario is moving northwestward at 9 kt, and this general motion is expected to continue, with a slight decrease in forward speed until dissipation, as Mario is steered by the low-level flow. The NHC track forecast has been adjusted a bit to the northeast, or right, of the previous forecast, closer to most of the latest consensus models. While the remnant low of Mario is forecast to dissipate well to the south of California, its remnant moisture will spread farther north, affecting portions of the southwestern United States by mid to late week. Locally heavy rainfall and some instances of flash flooding will be possible by Thursday. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 23.7N 118.3W 25 KT 30 MPH...POST-TROPICAL 12H 17/1200Z 24.7N 119.2W 20 KT 25 MPH...POST-TROP/REMNT LOW 24H 18/0000Z 25.6N 119.8W 20 KT 25 MPH...POST-TROP/REMNT LOW 36H 18/1200Z 26.3N 120.2W 15 KT 15 MPH...POST-TROP/REMNT LOW 48H 19/0000Z...DISSIPATED