000
WTPZ45 KNHC 020242
TCDEP5
 
Tropical Storm Octave Discussion Number   8
NWS National Hurricane Center Miami FL       EP152025
800 PM PDT Wed Oct 01 2025
 
The satellite presentation of Octave has improved slightly since the 
previous advisory, with better-defined curved banding developing on 
the south and west sides of the low-level center.  The cyclone 
continues to be influenced by moderate easterly wind shear, analyzed 
at around 22 kt by UW-CIMSS.  This shear is restricting outflow in 
the eastern semicircle and keeping the low-level center displaced on 
the eastern side of the deeper convection.  The most recent 
subjective Dvorak intensity estimate from TAFB was 3.5/55 kt, while 
the UW-CIMSS objective estimates have ranged from 45 to 58 kt since 
the prior advisory.  Based on a blend of these data, and considering 
the modest improvement in the satellite presentation during the past 
several hours, the initial intensity is held at 55 kt for this 
advisory.

Octave is estimated to be moving west-northwestward, or 290 degrees 
at 6 kt.  This general motion is expected to continue for the next 
several days as Octave is steered along the southern periphery of a 
subtropical ridge located to its north.  By days 4 and 5, Octave is 
forecast to slow considerably and turn northward, then eastward, as 
a longwave trough approaches from the northwest and the subtropical 
ridge to its east weakens due to the influence of a larger tropical 
cyclone developing offshore of the southwestern or west-central 
coast of Mexico.  The new NHC track forecast is similar to the 
previous one and remains close to a blend of the multi-model 
consensus and AI-based track aids.

Octave will remain over warm waters and within a moist environment 
for the next few days.  However, vertical wind shear is forecast to 
fluctuate between moderate and strong levels during the next 36 
hours, which should inhibit significant intensification during that 
period.  As a result, the official forecast indicates little change 
in strength through that time.  Some modest strengthening is then 
forecast between 48 and 96 hours as the shear relaxes, although sea 
surface temperatures will gradually cool and mid-level moisture is 
expected to decrease.  The official forecast now shows Octave 
reaching hurricane intensity by days 3 and 4, though this remains 
below the more aggressive solutions from some regional hurricane 
models.  By day 5, weakening should be well underway as Octave moves 
into a drier, more stable air mass, over cooler waters around 26C, 
and experiences increasing shear.  The official forecast is similar 
to the previous one and remains most closely aligned with the HCCA 
and FSSE intensity aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0300Z 12.2N 117.0W   55 KT  65 MPH
 12H  02/1200Z 12.6N 117.8W   55 KT  65 MPH
 24H  03/0000Z 13.1N 119.1W   55 KT  65 MPH
 36H  03/1200Z 13.5N 120.5W   55 KT  65 MPH
 48H  04/0000Z 14.0N 121.9W   60 KT  70 MPH
 60H  04/1200Z 14.5N 123.0W   60 KT  70 MPH
 72H  05/0000Z 15.0N 123.8W   65 KT  75 MPH
 96H  06/0000Z 15.7N 123.2W   65 KT  75 MPH
120H  07/0000Z 16.0N 121.5W   50 KT  60 MPH
 
$$
Forecaster Jelsema (CPHC)