Issued at 200 AM PDT Sat Oct 25 2025
000 WTPZ43 KNHC 250834 TCDEP3 Tropical Storm Sonia Discussion Number 3 NWS National Hurricane Center Miami FL EP182025 200 AM PDT Sat Oct 25 2025 Satellite imagery shows deep convection expanding over the low-level circulation center, with cloud-top temperatures near −80 C. Subjective Dvorak Current Intensity estimates from TAFB and SAB are in agreement at 2.5/35 kt, which is supported by the latest UW–CIMSS objective estimates. Based on the improving satellite presentation and these data, the depression has been upgraded to Tropical Storm Sonia, with the initial intensity set at 35 kt. Sonia has a brief window of opportunity to gradually strengthen over the weekend while it remains over warm waters and within a moist, low-shear environment. Strengthening should level off by Monday as southwesterly vertical wind shear begins to increase. By Tuesday, a combination of stronger shear, drier mid- to upper-level air, and cooler sea-surface temperatures should induce a gradual weakening trend. Simulated satellite imagery from the global models supports this scenario, depicting convection diminishing by midweek. As a result, Sonia is forecast to degenerate into a post-tropical remnant low by day 4. The NHC intensity forecast remains very similar to the previous one and continues to closely follow the consensus aids. The initial motion is toward the west, or 275/8 kt, along the southern side of a subtropical ridge that is expected to persist through the first half of the weekend. A turn toward the northwest is anticipated for a brief period late Sunday into early next week as a weakness develops in the ridge in response to a mid-latitude trough passing over the northern Pacific. A turn back toward the west is then expected by Tuesday and into midweek as the ridge restrengthens to the north. By day 5, Sonia is forecast to become increasingly influenced by the low-level trade wind flow, which should steer it southwestward. The latest NHC track forecast remains close to the previous advisory and lies between the HCCA and Google DeepMind solutions. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 13.3N 117.6W 35 KT 40 MPH 12H 25/1800Z 13.4N 118.6W 40 KT 45 MPH 24H 26/0600Z 13.4N 119.5W 45 KT 50 MPH 36H 26/1800Z 13.6N 120.4W 50 KT 60 MPH 48H 27/0600Z 14.1N 121.0W 50 KT 60 MPH 60H 27/1800Z 14.6N 121.6W 50 KT 60 MPH 72H 28/0600Z 15.2N 122.4W 45 KT 50 MPH 96H 29/0600Z 15.5N 125.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 30/0600Z 14.8N 128.3W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Gibbs (CPHC)
Source link