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Tropical Storm Sonia Discussion Number   4
NWS National Hurricane Center Miami FL       EP182025
800 AM PDT Sat Oct 25 2025

Sonia appears to be strengthening this morning. While it has been 
difficult to pinpoint Sonia's center, it appears to be well 
embedded within the central dense overcast. Subjective Dvorak 
estimates from TAFB and SAB have increased to 45 kt, and various 
objective intensity techniques from UW-CIMSS have also increased 
with a mean value near 45 kt, so that is initial intensity for this 
advisory.

Given the higher initial intensity, the intensity forecast for 
Sonia has also increased a little, and now shows the cyclone could 
approach hurricane strength tomorrow. Several models now show Sonia 
becoming a hurricane late this weekend. The new NHC intensity 
forecast is just below the model consensus, so an additional upward 
adjustment could be necessary in the next advisory. Beyond 2 days, 
Sonia is still expected to gradually weaken as a result of 
increasing shear and drier mid-level air wrapping into its 
circulation. Models still indicate that Sonia will lose its deep 
convection by day 4, and it will likely degenerate into a trough by 
the end of the forecast period.

Sonia has continued moving generally west. No substantial changes to 
the official track forecast were made aside from a slight northward 
tweak to account for the latest initial position of the tropical 
storm. In general, the tropical storm should keep on its current 
heading today, then slow and turn northwestward on Sunday. By the 
middle of next week, Sonia should turn back westward as it weakens 
and becomes steered by low-level flow. The spread in the model 
guidance is unusually high, so uncertainty in the track is slightly 
higher than normal, but the NHC forecast is still based on a blend 
of HCCA and GDM.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 13.5N 118.1W   45 KT  50 MPH
 12H  26/0000Z 13.6N 118.9W   50 KT  60 MPH
 24H  26/1200Z 13.7N 119.7W   55 KT  65 MPH
 36H  27/0000Z 13.9N 120.3W   60 KT  70 MPH
 48H  27/1200Z 14.4N 121.0W   60 KT  70 MPH
 60H  28/0000Z 14.9N 122.1W   55 KT  65 MPH
 72H  28/1200Z 15.2N 123.3W   45 KT  50 MPH
 96H  29/1200Z 15.0N 126.5W   30 KT  35 MPH...POST-TROPICAL
120H  30/1200Z...DISSIPATED
 
$$
Forecaster D. Zelinsky
 
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