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)