EPAC: OCTAVE - Post-Tropical

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 8
NWS National Hurricane Center Miami FL EP152025
800 PM PDT Wed Oct 01 2025

...OCTAVE HEADING WEST-NORTHWESTWARD OVER THE OPEN TROPICAL EAST
PACIFIC...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...12.2N 117.0W
ABOUT 875 MI...1405 KM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES




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)

[Astromanía]

Why I feel this will be one of those storms overachieving before dying due to cool waters

[cycloneye]

Tropical Storm Octave Discussion Number 9
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Thu Oct 02 2025

The overall satellite presentation of Octave has changed little
since the previous advisory, though the previously well-defined
curved banding to the south and west of the center has become more
ragged in recent hours. The cyclone continues to be affected by
moderate easterly shear, analyzed at around 17 kt by UW-CIMSS. This
shear is restricting outflow in the eastern semicircle and keeping
the low-level center near the eastern edge of the deep convection.
Recent subjective Dvorak estimates from TAFB and SAB were 3.5/55 kt
and 4.0/65 kt, respectively, while UW-CIMSS objective estimates have
ranged from 48 to 59 kt over the past few hours. Based on a blend of
these data, and with little change in the overall structure, the
initial intensity is held at 55 kt.

Octave is moving slightly north of due west, or 280 degrees at 7 kt.
A west to west-northwest motion is expected during the next few days
as the cyclone is steered along the southern flank of a subtropical
ridge to its north. After day 3, Octave should slow as a longwave
trough approaches from the northwest, weakening the ridge and
overall steering flow. A developing disturbance or tropical
cyclone offshore of the southwestern or west-central coast of
Mexico is then forecast to erode the subtropical ridge to the east
of Octave, causing the cyclone to turn eastward by days 4 and 5.
The updated NHC forecast has been adjusted slightly southward to
account for Octave’s more westward recent motion and the latest
model trends. Considerable along- and cross-track spread remains
in the extended range, and the forecast track represents a blend of
the multi-model consensus and AI-based guidance.

Octave will remain over warm water and within a moist environment
during the next few days. However, vertical wind shear is expected
to fluctuate between moderate and strong levels during the next 36
hours, which should prevent significant intensification. As a
result, little change in strength is forecast during this period.
Some modest strengthening is possible between 48 and 96 hours as
shear decreases, though cooling sea surface temperatures and
gradually drier mid-level air should limit intensification. Octave
is still forecast to reach hurricane strength by days 3 and 4,
remaining below some of the more aggressive hurricane regional model
solutions. By day 5, weakening is likely as Octave moves into a
more stable, drier air mass and encounters increasing southeasterly
shear. The forecast remains close to the previous one and lies near
the higher end of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 12.1N 117.9W 55 KT 65 MPH
12H 02/1800Z 12.3N 118.6W 55 KT 65 MPH
24H 03/0600Z 12.8N 119.8W 55 KT 65 MPH
36H 03/1800Z 13.3N 121.1W 55 KT 65 MPH
48H 04/0600Z 13.9N 122.4W 55 KT 65 MPH
60H 04/1800Z 14.4N 123.5W 60 KT 70 MPH
72H 05/0600Z 14.9N 124.0W 65 KT 75 MPH
96H 06/0600Z 15.6N 123.4W 65 KT 75 MPH
120H 07/0600Z 15.6N 121.1W 50 KT 60 MPH

$$
Forecaster Jelsema (CPHC)

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 10
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Thu Oct 02 2025

...OCTAVE SHOWING LITTLE CHANGE IN STRENGTH...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...12.5N 118.5W
ABOUT 915 MI...1470 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES


Tropical Storm Octave Discussion Number 10
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Thu Oct 02 2025

Octave continues to be affected by strong easterly vertical wind
shear associated with an upper-level anticyclone to its northeast.
The cloud pattern has not changed much in organization, with some
limited convective banding features over the southern and western
portions of the circulation. Upper-tropospheric outflow continues
to be impeded to the east of the cyclone. The advisory intensity
estimate is held at 55 kt in agreement with a subjective Dvorak
estimate from TAFB. Objective values from UW-CIMSS range from 49
to 54 kt at this time.

The system is moving west-northwestward at around 285/7 kt. Octave
is currently being steered by the flow on the southern perimeter of
a mid-level ridge. This ridge is predicted to weaken over the next
few days, which should cause the system to slow and turn northward
in around 72 hours. A generally eastward motion is expected by the
end of the forecast period, as Octave becomes drawn into the larger
circulation of a developing tropical cyclone off the southwest coast
of Mexico. The official track forecast is close to the latest
corrected dynamical consensus model, HCCA, track.

Dynamical guidance indicates that the vertical wind shear over
Octave will abate in a few days while the system traverses
marginally warm ocean waters. Thus, there is a relatively small
window of opportunity for strengthening later in the forecast
period. This is also shown in the official intensity forecast,
which is at the high end of the model guidance suite.

FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 12.5N 118.5W 55 KT 65 MPH
12H 03/0000Z 12.8N 119.3W 55 KT 65 MPH
24H 03/1200Z 13.3N 120.5W 55 KT 65 MPH
36H 04/0000Z 13.8N 121.8W 55 KT 65 MPH
48H 04/1200Z 14.4N 123.0W 55 KT 65 MPH
60H 05/0000Z 15.0N 123.8W 60 KT 70 MPH
72H 05/1200Z 15.3N 124.0W 65 KT 75 MPH
96H 06/1200Z 15.9N 122.9W 65 KT 75 MPH
120H 07/1200Z 16.0N 120.5W 50 KT 60 MPH

$$
Forecaster Pasch

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 11
NWS National Hurricane Center Miami FL EP152025
200 PM PDT Thu Oct 02 2025

...OCTAVE HAS CHANGED LITTLE IN ORGANIZATION SINCE EARLIER TODAY...


SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...12.7N 119.0W
ABOUT 925 MI...1485 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


Tropical Storm Octave Discussion Number 11
NWS National Hurricane Center Miami FL EP152025
200 PM PDT Thu Oct 02 2025

Octave continues to be disrupted by strong easterly vertical wind
shear. There is a rather sharp edge of the cloud shield on the
eastern side of the upper-level cloud pattern and the low-level
center remains near this eastern edge. Convective banding features
are not very well defined and the upper-tropospheric outflow
continues to be inhibited to the east of the system. The advisory
intensity has been adjusted to 50 kt based on a recent ASCAT
overpass and the 34-kt wind radii have also been adjusted slightly
based on the scatterometer data.

Center fixes indicate that the motion remains west-northwestward,
or 285/7 kt. The tropical cyclone continues to move along the
southern side of a weak mid-level subtropical ridge, and should
continue to do so for the next couple of days. By 72 hours or so,
Octave should turn northward and slow down as it encounters a
weakness in the ridge. Later in the forecast period, the system is
expected to turn eastward as it begins to become drawn into a larger
developing tropical cyclone off the southwest coast of Mexico. The
official forecast track is similar to the previous one also similar
to the multi-model consensus prediction.

Dynamical models indicate that the vertical wind shear over Octave
is not expected to decrease significantly for the next couple of
days. Later in the forecast period, the shear is likely to lessen
although the air mass is expected to become somewhat drier by that
time and the developing tropical cyclone to the east of Octave could
also have a negative influence. The official forecast calls for
some re-strengthening around day 3, however it is above most of the
model guidance. This should be considered a low-confidence
forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 02/2100Z 12.7N 119.0W 50 KT 60 MPH
12H 03/0600Z 13.0N 119.9W 50 KT 60 MPH
24H 03/1800Z 13.5N 121.1W 50 KT 60 MPH
36H 04/0600Z 14.0N 122.3W 50 KT 60 MPH
48H 04/1800Z 14.6N 123.4W 50 KT 60 MPH
60H 05/0600Z 15.0N 123.9W 55 KT 65 MPH
72H 05/1800Z 15.3N 123.7W 60 KT 70 MPH
96H 06/1800Z 15.5N 123.5W 60 KT 70 MPH
120H 07/1800Z 15.7N 120.5W 45 KT 50 MPH

$$
Forecaster Pasch

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 13
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Fri Oct 03 2025

...OCTAVE WEAKENS SLIGHTLY AND CONTINUES WEST-NORTHWESTWARD...


SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...13.1N 120.4W
ABOUT 965 MI...1555 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


Tropical Storm Octave Discussion Number 13
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Fri Oct 03 2025

Octave remains a sheared tropical cyclone, with the low-level center
mostly exposed and displaced east of a recent burst of deep
convection. The latest subjective Dvorak current intensity estimates
from TAFB and SAB are 3.5/55 kt and 3.0/45 kt, respectively, while
the UW-CIMSS objective estimates have ranged between 35 and 44 kt
during the past several hours. A recent 03/0435Z Metop-B ASCAT pass
was helpful in determining the tropical-storm-force wind radii and
the center location, and it also indicated peak winds of 38 kt.
Based on a blend of these data, and accounting for some
undersampling in the scatterometer data, the initial intensity is
set at 45 kt for this advisory.

Octave is estimated to be moving west-northwestward, or 290 degrees
at 7 kt. This general motion is expected to continue through
tonight as the cyclone is steered along the southern periphery of a
weak subtropical ridge located to its north. Octave is forecast to
slow considerably and turn northward by late Saturday, followed by a
sharp eastward turn by late Sunday as a mid-level 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 prediction and lies near a blend
of the multi-model consensus aids.

Octave will remain over warm waters and within a moist environment
for the next few days. East-southeasterly vertical wind shear is
expected to continue impacting the cyclone for the next 12 to 24
hours, which should inhibit strengthening. Beyond 24 hours, the
shear is forecast to decrease to light levels, while the cyclone
remains over waters near 27C and within a sufficiently moist
environment. These conditions should allow for some modest
strengthening over the weekend. By days 4 and 5, Octave is forecast
to encounter increasing southeasterly shear and a drier mid-level
environment, which should result in steady weakening. The official
intensity forecast has been lowered slightly to account for a
notable decrease among the various intensity aids. The forecast now
lies above most of the intensity guidance throughout the period, and
future forecasts may need to adjust the intensity downward further
if the weakening trends in the guidance persist.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 13.1N 120.4W 45 KT 50 MPH
12H 03/1800Z 13.6N 121.3W 45 KT 50 MPH
24H 04/0600Z 14.1N 122.6W 45 KT 50 MPH
36H 04/1800Z 14.6N 123.6W 50 KT 60 MPH
48H 05/0600Z 15.1N 124.0W 55 KT 65 MPH
60H 05/1800Z 15.5N 123.9W 55 KT 65 MPH
72H 06/0600Z 15.5N 123.3W 50 KT 60 MPH
96H 07/0600Z 15.4N 121.8W 40 KT 45 MPH
120H 08/0600Z 15.1N 119.4W 35 KT 40 MPH

$$
Forecaster Jelsema (CPHC)

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 14
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Fri Oct 03 2025

...OCTAVE CONTINUES WEST-NORTHWESTWARD AND IS NOT EXPECTED TO
CHANGE SIGNIFICANTLY TODAY...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...13.4N 121.0W
ABOUT 980 MI...1575 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES



Tropical Storm Octave Discussion Number 14
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Fri Oct 03 2025

Octave has changed little during the past several hours. The system
still appears to be sheared, and satellite intensity estimates are
similar to six hours ago, so the intensity is held at 45 kt for this
advisory. The outlook for Octave is relatively high confidence for
the next day or so. Octave should continue moving west-northwestward
near 7 kt, steered by a small mid-level ridge centered between
Octave and the Baja California Peninsula. During that time, it
should also remain somewhat sheared with its intensity only
fluctuating slightly up or down over that period. Confidence in the
NHC forecast is high through Saturday.

However, by Saturday evening, the uncertainty in the forecast grows
substantially. First, the aforementioned ridge is expected to
weaken, resulting in very weak steering flow for the following
couple of days. A trough over the far northern east Pacific will
probably cause Octave to turn and drift eastward during that time.
After that, another larger disturbance to Octave's east will likely
also influence Octave's track, potentially causing it to move faster
toward the east by the middle of next week. With steering currents
weak, only small changes in the environment could have a large
impact on Octave's track. The spread in the track guidance grows
substantially beyond 48 h, so confidence in the forecast is much
lower at that point.

The intensity is likewise uncertain beyond 24 to 36 h. The shear
affecting Octave is expected to lessen, and the tropical storm
should be in an environment otherwise conducive for strengthening
for at least a day or two. Octave's relatively small size could make
it susceptible to relatively quick changes in intensity, up or
down. All of the traditional dynamical intensity models forecast
that Octave will change little in strength during that period. On
the other hand, Google DeepMind (GDM) ensemble shows a very
different story with an unusually large range of possibilities
between tropical depression and major hurricane strength. The NHC
forecast has not been changed, and is on the high end of the
traditional guidance, but below the GDM ensemble mean. Because of
this discrepancy, confidence in the intensity forecast is low,
despite the fact that no changes were made to the NHC forecast with
this advisory.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 13.4N 121.0W 45 KT 50 MPH
12H 04/0000Z 13.8N 122.0W 45 KT 50 MPH
24H 04/1200Z 14.4N 123.2W 45 KT 50 MPH
36H 05/0000Z 15.0N 123.9W 50 KT 60 MPH
48H 05/1200Z 15.4N 124.1W 55 KT 65 MPH
60H 06/0000Z 15.6N 123.7W 55 KT 65 MPH
72H 06/1200Z 15.7N 123.0W 50 KT 60 MPH
96H 07/1200Z 15.4N 121.2W 40 KT 45 MPH
120H 08/1200Z 15.0N 119.0W 35 KT 40 MPH

$$
Forecaster D. Zelinsky

[Sciencerocks]

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 16
NWS National Hurricane Center Miami FL EP152025
800 PM PDT Fri Oct 03 2025

...OCTAVE MOVING WEST-NORTHWESTWARD AND HOLDING STEADY...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...13.8N 122.7W
ABOUT 1045 MI...1685 KM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES

Tropical Storm Octave Discussion Number 16
NWS National Hurricane Center Miami FL EP152025
800 PM PDT Fri Oct 03 2025

Octave still has the appearance of a sheared tropical cyclone.
Infrared geostationary satellite imagery shows that cloud top
temperatures have generally warmed over the past few hours. Similar
to the previous night, isolated bursts of convection are
currently forming within the western portion of the circulation.
This can also be seen on an AMSR2 microwave pass from earlier
this afternoon that had a fragmented curved band wrapping around
the southern and western sides of Octave. The initial intensity is
held at 50 kt, representing a blend of the subjective and objective
Dvorak estimates that range between 39 to 55 kt.

The tropical storm is still moving west-northwestward at 7 kt.
Octave is expected to turn more to the northwest soon, followed by
a northward motion on Sunday with a decreased forward speed as the
mid-level ridge to the east weakens. By early next week, the
cyclone should begin to move eastward, but the track guidance
envelope is quite large by the middle-to-latter portions of the
forecast period. This is because models differ on how much Octave
will interact with a trough over the western United States and how
quickly a developing disturbance (Invest 99-E) will organize. The
only changes to the latest NHC track forecast are that it lies
slightly south and west of the previous forecast in the first 36 h,
due the delayed turn to the northwest.

Vertical wind shear is gradually relaxing over the cyclone which
could lead to some slight strengthening in about a day. Most of the
reliable models are no longer showing Octave becoming a hurricane.
By 48 h, the vertical wind shear is expected to increase and
gradually weaken the cyclone as it moves eastward towards the much
larger system to its east. Only minor adjustments have been made
to the official intensity forecast, which lies in the middle of the
guidance suite.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 13.8N 122.7W 50 KT 60 MPH
12H 04/1200Z 14.2N 123.5W 50 KT 60 MPH
24H 05/0000Z 14.8N 124.2W 55 KT 65 MPH
36H 05/1200Z 15.3N 124.2W 55 KT 65 MPH
48H 06/0000Z 15.5N 123.9W 55 KT 65 MPH
60H 06/1200Z 15.7N 123.1W 50 KT 60 MPH
72H 07/0000Z 15.5N 121.8W 45 KT 50 MPH
96H 08/0000Z 15.0N 120.0W 40 KT 45 MPH
120H 09/0000Z 14.8N 117.2W 35 KT 40 MPH

$$
Forecaster Bucci

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 17
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Sat Oct 04 2025

...OCTAVE MOVING WEST-NORTHWESTWARD...


SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...14.2N 123.2W
ABOUT 1055 MI...1700 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES





Tropical Storm Octave Discussion Number 17
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Sat Oct 04 2025

Octave is still trying to become better organized this morning, as
shear starts to decrease over the system. In recent satellite
images, a large convective band has started to become better
established on the western side of the system with cold cloud tops
near -80 C. However, recent satellite-derived winds depicted peak
winds of only 34 kt, although it did not sample the convective band
to the west. Subjective and objective satellite intensity estimates
have held steady and range from 45 to 55 kt. Using a blend of these
estimates and the lower satellite derived wind speeds, the intensity
is lowered to 45 kt for this advisory.

The storm is moving west-northwest at an estimated motion of 290/7
kt. Octave should gradually turn towards the northwest later today,
followed by a northward turn on Sunday with a decrease in forward
speed as steering currents weaken. In about 48 h, there continue to
be differences within the track guidance envelope and it is due to
how much interaction occurs with a trough to the north of the system
and a developing disturbance (Invest 99E) to the east. The latest
NHC track forecast is similar to the previous in the short-term, but
is slightly faster with the eastward motion closest to the HCCA and
Google DeepMind solutions.

Wind shear has started to decrease over the system, with marginally
warm sea surface temperatures near 27 C along the forecast track.
Thus, slight intensification is possible over the next day or two.
By 48 h, the vertical wind shear is expected to increase and a
weakening trend is forecast as it interacts with a much larger
system to the east. The NHC intensity forecast is near the previous,
showing some slight strengthening possible, although a lower peak
intensity and lies near the simple intensity consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 14.2N 123.2W 45 KT 50 MPH
12H 04/1800Z 14.6N 123.9W 50 KT 60 MPH
24H 05/0600Z 15.2N 124.1W 50 KT 60 MPH
36H 05/1800Z 15.6N 123.8W 50 KT 60 MPH
48H 06/0600Z 15.8N 123.0W 45 KT 50 MPH
60H 06/1800Z 15.9N 121.9W 40 KT 45 MPH
72H 07/0600Z 15.5N 120.5W 35 KT 40 MPH
96H 08/0600Z 15.0N 118.5W 30 KT 35 MPH
120H 09/0600Z 15.6N 115.2W 30 KT 35 MPH

$$
Forecaster Kelly

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 18
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Sat Oct 04 2025

...OCTAVE CONTINUES NORTHWESTWARD...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...14.6N 123.6W
ABOUT 1060 MI...1710 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


Tropical Storm Octave Discussion Number 18
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Sat Oct 04 2025

Octave's overall appearance has remained steady this morning, with
its center embedded within a large area of persistent deep
convection. A recent AMSR-2 microwave pass also indicates that the
tropical storm is maintaining a well-organized structure, with
curved bands apparent in the microwave imagery. A blend of
subjective and objective satellite intensity estimates, and the
persistence of deep convection throughout the morning, support a
slight increase in the intensity to 50 kt for this advisory.

The storm is moving northwestward with an estimated motion of 310/6
kt. This motion is expected to continue today before beginning a
northward and eventually eastward turn later this weekend and early
next week. The precise timing of the eastward turn is somewhat
uncertain, as it depends on the interaction of Octave with Invest
99E to its east and a trough to its north. The NHC track forecast
for this advisory is similar to the prior advisory and represents a
blend of track consensus aids and the faster Google DeepMind
solution.

Vertical wind shear is expected to remain weak for the next 24 h.
Within this narrow window of time, conditions are forecast to
remain marginally favorable for some slight intensification.
However, after 24 h as Octave turns toward the east, wind shear is
expected to increase as the storm interacts with the much larger
system to its east. Late this weekend, Octave is forecast to begin
a weakening trend that will continue throughout the forecast
period. The current NHC intensity forecast is slightly higher
than the prior advisory during the next day or so, and it remains
near the middle of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 14.6N 123.6W 50 KT 60 MPH
12H 05/0000Z 15.0N 124.1W 55 KT 65 MPH
24H 05/1200Z 15.5N 124.1W 55 KT 65 MPH
36H 06/0000Z 15.9N 123.5W 50 KT 60 MPH
48H 06/1200Z 16.0N 122.6W 45 KT 50 MPH
60H 07/0000Z 16.0N 121.4W 40 KT 45 MPH
72H 07/1200Z 15.7N 120.2W 35 KT 40 MPH
96H 08/1200Z 15.2N 118.0W 30 KT 35 MPH
120H 09/1200Z 16.2N 114.1W 30 KT 35 MPH

$$
Forecaster Hogsett

[Kingarabian]

Looking pretty good this morning

[Sciencerocks]

[cycloneye]

Tropical Storm Octave Discussion Number 19
NWS National Hurricane Center Miami FL EP152025
200 PM PDT Sat Oct 04 2025

Deep convection has continued to pulse today near the center of
Octave. Recent visible and microwave satellite imagery indicates a
well-organized inner-core structure, which was confirmed by a recent
ASCAT scatterometer pass. Based on the current satellite
presentation and a blend of subjective and objective satellite
intensity estimates, the intensity is increased slightly to 55 kt
for this advisory.

The storm has begun to turn more northward and is now moving
north-northwestward with an estimated motion of 330/5 kt. A
continued northward and eventual eastward turn is forecast this
weekend and early next week. The track forecast depends somewhat on
the interaction of Octave with Tropical Storm Priscilla to its east
and a trough to its north during the next several days. The NHC
track forecast for this advisory is similar to the prior advisory
and represents a blend of track consensus aids and the Google
DeepMind solution.

Vertical wind shear is expected to remain weak for the next 24 h.
During this period, conditions are forecast to remain marginally
favorable for some slight intensification. However, after 24 h as
Octave turns toward the east, wind shear is expected to increase as
the storm interacts with trough and the larger tropical storm to
its east. Late this weekend, Octave is forecast to begin a
weakening trend that will continue until the system dissipates
after 96 h. The current NHC intensity forecast is slightly higher
than the prior advisory during the next day or so, and it remains
near the middle of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 14.9N 123.9W 55 KT 65 MPH
12H 05/0600Z 15.3N 124.0W 60 KT 70 MPH
24H 05/1800Z 15.7N 123.6W 60 KT 70 MPH
36H 06/0600Z 15.9N 122.7W 55 KT 65 MPH
48H 06/1800Z 16.0N 121.6W 45 KT 50 MPH
60H 07/0600Z 15.8N 120.5W 40 KT 45 MPH
72H 07/1800Z 15.5N 119.3W 35 KT 40 MPH
96H 08/1800Z 15.3N 116.8W 30 KT 35 MPH
120H 09/1800Z...DISSIPATED

$$
Forecaster Hogsett

[cycloneye]

BULLETIN
Tropical Storm Octave Advisory Number 20
NWS National Hurricane Center Miami FL EP152025
800 PM PDT Sat Oct 04 2025

...OCTAVE SLOWLY MOVING NORTH-NORTHWESTWARD...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...15.4N 124.1W
ABOUT 1060 MI...1705 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES



Tropical Storm Octave Discussion Number 20
NWS National Hurricane Center Miami FL EP152025
800 PM PDT Sat Oct 04 2025

Octave's organization has held relatively steady since the previous
advisory. Overshooting cloud tops continue to burst through a
modestly-sized central dense overcast. An earlier AMSR2 37 GHz
overpass showed a curved band wrapping around the northern and
western quadrants of the storm. Subjective and objective Dvorak
estimates range from 42 kt to 65 kt, and the initial intensity is
held at 55 kt representing a blend of these values.

The storm is still slowing moving north-northwestward at 4 kt. A
turn to the north is expected shortly, followed by an accelerated
eastward motion in about 24 hours. Much of this track prediction
depends on the evolution of Tropical Storm Priscilla, located about
1100 miles to the east of Octave. The NHC track forecast has
shifted slightly north of the previous track forecast due to a more
northward initial position and lies between HCCA and the Google Deep
Mind ensemble mean.

Octave has a short window of 18-24 hours with relatively conducive
atmospheric conditions to intensify. Weak vertical wind shear and
adequate mid-level moisture should allow Octave to strengthen. By
Monday, increasing upper-level winds are expected to disrupt
Octave's circulation and induce a gradual weakening trend. Octave
is still forecast to open into a trough on the southern side of
Tropical Storm Priscilla by the end of the forecast period. Only
minor adjustments were made to the latest official intensity
prediction.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 15.4N 124.1W 55 KT 65 MPH
12H 05/1200Z 15.8N 124.0W 60 KT 70 MPH
24H 06/0000Z 16.2N 123.2W 55 KT 65 MPH
36H 06/1200Z 16.2N 122.3W 50 KT 60 MPH
48H 07/0000Z 16.1N 121.1W 45 KT 50 MPH
60H 07/1200Z 15.9N 120.0W 40 KT 45 MPH
72H 08/0000Z 15.5N 118.8W 35 KT 40 MPH
96H 09/0000Z 15.6N 116.4W 30 KT 35 MPH
120H 10/0000Z...DISSIPATED

$$
Forecaster Bucci

[Sciencerocks]

[cycloneye]

Tropical Storm Octave Discussion Number 21
NWS National Hurricane Center Miami FL EP152025
200 AM PDT Sun Oct 05 2025

Satellite imagery indicates that Octave remains a compact tropical
cyclone, with the diameter of its central dense overcast (CDO) near
150 miles. Intermittent bursts of deep convection continue near the
embedded center, with cloud-top temperatures occasionally exceeding
−80 degrees C. Subjective Dvorak Current Intensity estimates are
4.0/65 kt from TAFB and 3.5/55 kt from SAB, while objective
estimates are as high as 60 kt. An ASCAT-B pass at 0534 UTC
depicted the small and compact system, with peak surface winds just
over 50 kt and tropical-storm-force winds extending only about 60 n
mi from the center. A blend of these data supports an initial
intensity of 60 kt for this advisory.

Octave is now moving slowly north-northeastward at about 3 kt, and
this motion is expected to continue today while the storm gradually
turns northeastward within a weak steering pattern between an
upper-level trough along the U.S. West Coast and Tropical Cyclone
Priscilla, which is drifting northwestward well to the east off the
southwestern coast of Mexico. Beginning Monday, Octave should turn
eastward and gradually accelerate. By midweek, forecast uncertainty
increases significantly as Octave becomes increasingly influenced by
Priscilla’s evolution and track. The new NHC forecast track is very
similar to the previous advisory and closely follows the consensus
aids, with Octave expected to dissipate by day 5 (Thursday night) as
it becomes absorbed by the larger Tropical Cyclone Priscilla.

Octave has intensified slightly since the previous advisory, and
with the environment remaining marginally conducive for the next 12
to 18 hours, some additional strengthening cannot be ruled out.
Guidance, however, generally supports the intensity holding steady
during this period, which is reflected in this forecast through the
day today. Thereafter, increasing vertical wind shear, combined with
the interaction with Priscilla, should induce a gradual weakening
trend. Octave is forecast to open up into a trough and be absorbed
by Priscilla by the end of the forecast period. The intensity
forecast remains close to the previous NHC advisory and near the
middle to upper portion of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 15.6N 124.1W 60 KT 70 MPH
12H 05/1800Z 15.9N 123.8W 60 KT 70 MPH
24H 06/0600Z 16.1N 122.9W 55 KT 65 MPH
36H 06/1800Z 16.1N 121.9W 50 KT 60 MPH
48H 07/0600Z 15.9N 120.7W 45 KT 50 MPH
60H 07/1800Z 15.5N 119.6W 40 KT 45 MPH
72H 08/0600Z 15.3N 118.4W 35 KT 40 MPH
96H 09/0600Z 16.3N 115.4W 30 KT 35 MPH
120H 10/0600Z...DISSIPATED

$$
Forecaster Gibbs (CPHC)

[Kingarabian]

Octave has been pretty resilient. Lsts see if it can make it to hurricane status

[cycloneye]

EP, 15, 2025100512, , BEST, 0, 156N, 1239W, 70, 987, HU

[cycloneye]

BULLETIN
Hurricane Octave Advisory Number 22
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Sun Oct 05 2025

...OCTAVE STRENGTHENS AND BECOMES THE NINTH HURRICANE OF THE 2025
EAST PACIFIC HURRICANE SEASON...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...15.7N 123.7W
ABOUT 1025 MI...1650 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NE OR 45 DEGREES AT 3 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES





Hurricane Octave Discussion Number 22
NWS National Hurricane Center Miami FL EP152025
800 AM PDT Sun Oct 05 2025

Octave has become better organized since the previous advisory, with
banded convection becoming more prominent on the east side of the
center. A 05/1008 UTC AMSR2 pass showed an eye on microwave
imagery. Some earlier GOES-18 images from around 1100-1200 UTC
showed a possible eye, but deep, banded convection has covered it up
since that time. Objective intensity estimates from UW-CIMSS have
risen to the 60-75 kt range, while the TAFB Dvorak estimate remains
T-4.0/65 kt. Based on the aforementioned intensity estimates, as
well as the improved inner-core organization as noted on microwave
images, Octave's initial intensity is increased to 70 kt, making it
the ninth hurricane of the 2025 east Pacific hurricane season.

Octave appears to be drifting slowly northeastward, or 045 degrees
at 3 kt. A turn toward the east at a slightly faster forward speed
is expected Monday as the cyclone is pushed in that direction by an
upper-level trough to its northwest. By early Tuesday, the main
weather feature affecting Octave's track will likely be a large and
powerful Priscilla, which should cause Octave to turn toward the
east-southeast. By Wednesday, models are in agreement that Octave
should be located south of Priscilla. Once Octave gets southeast of
Priscilla, an acceleration toward the northeast is expected. The
new NHC track forecast takes Octave a bit faster toward the east,
but not quite as fast as the latest HFIP Corrected Consensus (HCCA)
model. The official forecast lies a bit south of the latest Google
Deep Mind ensemble mean.

Octave is currently moving through sea-surface temperatures between
26 and 27 degrees C, and it is forecast to remain over similar water
temperatures for the remainder of its lifetime. The shear is
expected to remain fairly low for another 24-36 h. A decent number
of typically reliable intensity models are showing weakening,
especially in the 12 to 36 hour period, so confidence is not very
high as to whether Octave could strengthen slightly, maintain its
intensity, or weaken during the next day or so. The new NHC
intensity forecast is higher than the previous one (mainly due to
the stronger initial intensity), and is near the higher end of the
guidance over the first day. By 36 h, increasing easterly shear,
partially the result of the outflow from Priscilla, is expected to
lead to weakening. The NHC intensity forecast is closer to the
middle of the guidance envelope from 36 h onward. Octave is
forecast to dissipate in 4 to 5 days as it becomes absorbed by the
larger circulation of Priscilla, and the models are in pretty good
agreement on this scenario.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 15.7N 123.7W 70 KT 80 MPH
12H 06/0000Z 15.9N 123.1W 70 KT 80 MPH
24H 06/1200Z 16.1N 122.1W 60 KT 70 MPH
36H 07/0000Z 15.9N 121.0W 55 KT 65 MPH
48H 07/1200Z 15.7N 119.9W 50 KT 60 MPH
60H 08/0000Z 15.3N 118.8W 45 KT 50 MPH
72H 08/1200Z 15.3N 117.3W 40 KT 45 MPH
96H 09/1200Z 17.6N 112.5W 30 KT 35 MPH
120H 10/1200Z...DISSIPATED

$$
Forecaster Hagen