Issued at 800 PM PDT Sat Oct 25 2025
000 WTPZ43 KNHC 260233 TCDEP3 Tropical Storm Sonia Discussion Number 6 NWS National Hurricane Center Miami FL EP182025 800 PM PDT Sat Oct 25 2025 Sonia seems to be holding steady this evening. Data from a microwave satellite overpass showed the circulation was still open to the west, with a curved band wrapped around the eastern and southern portions of the storm. Convection has waned during the past few hours and objective and subjective satellite intensity estimates have remained generally stable. The initial intensity is held at 45 kt for this advisory. The storm is moving westward at 4 kt. There is still a large spread in the model guidance through the forecast period. The forecast reasoning has not changed. A steadily strengthening system is expecting to turn west-northwestward to northwestward. The model forecasts with shallower vortex structures tend to remain on a more westward trajectory while the deeper cyclones tend to track more poleward. The primary steering features influencing Sonia are a subtropical ridge extending to the north of the tropical storm and an amplifying mid-latitude trough that is expected to erode the ridge in the coming days. The latest NHC track forecast is similar to the previous prediction and lies south of the corrected consensus aid and north of the Google DeepMind ensemble mean. Sonia has about a day or so to gradually strengthen before atmospheric and oceanic conditions begin to significantly inhibit intensification. After that time, vertical wind shear is expected to increase, with sea surface temperatures decreasing, particularly if Sonia takes a more northern path. The model guidance envelope shifted noticeably lower this cycle, though only minimal changes were made to the official intensity forecast. The latest prediction lies near the top of the guidance, close to HAFS-A, peaking in about 36 hours, and then calls for Sonia to become a post-tropical cyclone by day 3. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 13.5N 119.3W 45 KT 50 MPH 12H 26/1200Z 13.5N 119.8W 50 KT 60 MPH 24H 27/0000Z 13.8N 120.4W 55 KT 65 MPH 36H 27/1200Z 14.2N 121.3W 60 KT 70 MPH 48H 28/0000Z 14.7N 122.3W 55 KT 65 MPH 60H 28/1200Z 14.9N 123.8W 45 KT 50 MPH 72H 29/0000Z 15.0N 125.4W 35 KT 40 MPH...POST-TROPICAL 96H 30/0000Z 14.8N 128.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 31/0000Z...DISSIPATED $$ Forecaster Bucci
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