Issued at 800 AM PDT Sun Oct 26 2025
000 WTPZ43 KNHC 261446 TCDEP3 Tropical Storm Sonia Discussion Number 8 NWS National Hurricane Center Miami FL EP182025 800 AM PDT Sun Oct 26 2025 Deep convection returned over the low-level center overnight, but over the last several hours satellite imagery shows the convective structure has become a little more broken. The low-level center is likely situated on the southern end of the convective shield due to southerly wind shear. The latest subjective satellite intensity estimates were both data-T 3.0 from both TAFB and SAB. The objective intensity estimates from UW-CIMSS range from 35 to 50 kt. Using these estimates, the initial intensity will be held at 45 kt for this advisory. Sonia is moving slowly westward at an estimated motion of 280/03 kt. The system seems to be gradually turning towards the west-northwest towards a weakness in the subtropical ridge, with a continued slow forward motion the next day or so. As the system begins to weaken and become a more shallow vortex, the system should turn back toward the west within the low-level wind flow at a sightly faster forward speed. The latest NHC forecast is slightly near the previous and lies between the corrected consensus HCCA and Google DeepMind solutions. The storm will continue to deal with moderate wind shear, but will remain over warm sea surface temperatures for another day or so. Thus, little change in intensity is forecast, with the potential for some slight strengthening today. Beyond the 24-36 h time period, a weakening trend is forecast due to an increase in wind shear, and sea surface temperatures cooling along the forecast track. Water vapor satellite imagery shows abundant dry air to the west of the system and mid-level RH values drop into the 40 percent range in 2 to 3 days. The combination of dry air and shear should cause the system to gradually lose convection, and become a remnant low by 60 hours. This forecast is in good agreement with the global model simulated IR satellite solutions, and the latest NHC intensity forecast follows these trends, with the remnant low dissipating by the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 13.7N 119.9W 45 KT 50 MPH 12H 27/0000Z 13.9N 120.3W 50 KT 60 MPH 24H 27/1200Z 14.3N 121.2W 45 KT 50 MPH 36H 28/0000Z 14.6N 122.4W 45 KT 50 MPH 48H 28/1200Z 14.9N 123.5W 35 KT 40 MPH 60H 29/0000Z 15.0N 125.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 29/1200Z 15.1N 127.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 30/1200Z 14.2N 130.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 31/1200Z...DISSIPATED $$ Forecaster Kelly
