330 
WTPZ43 KNHC 290241
TCDEP3
 
Tropical Storm Sonia Discussion Number  18
NWS National Hurricane Center Miami FL       EP182025
800 PM PDT Tue Oct 28 2025
 
Sonia appears to have finally succumbed to the strong southerly 
shear analyzed by UW-CIMSS to be near 26 kt, while moving over 
cooler waters below 26C and into a drier mid-level environment with 
humidity values below 50 percent.  Deep convection was sheared away 
from the center around or shortly after 1800 UTC and has not 
returned, indicating that Sonia’s time as a tropical cyclone is 
nearly over.  The latest subjective Dvorak current intensity 
estimates from TAFB and SAB are 2.5/35 kt and 2.0/30 kt, 
respectively, while objective estimates from UW-CIMSS range from 28 
to 39 kt.  Based on a blend of these data, the initial intensity for 
this advisory is held at, perhaps a generous, 35 kt.

Sonia is now moving westward, or 280 degrees at 8 kt.  This general 
motion is expected to continue through dissipation.  The official 
track forecast is very similar to the previous one and represents a 
blend of the HCCA, GDMI, and FSSE track aids.  

Strong southerly shear is expected to persist during the next day or 
so while Sonia remains over cool waters of 25-26C and within dry 
mid-level air below 50 percent.  As a result, gradual weakening is 
anticipated, and Sonia is forecast to become a post-tropical remnant 
low later tonight and dissipate by Thursday.  The intensity forecast 
is unchanged from the previous advisory and remains closely aligned 
with the various intensity consensus aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0300Z 15.4N 125.3W   35 KT  40 MPH
 12H  29/1200Z 15.4N 126.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 24H  30/0000Z 15.2N 129.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  30/1200Z 14.8N 131.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  31/0000Z...DISSIPATED
 
$$
Forecaster Jelsema (CPHC)