东太平洋热带风暴“奥克塔夫”(15E.Octave)

ygsj24

706
WTPZ45 KNHC 010257
TCDEP5

Tropical Storm Octave Discussion Number   4
NWS National Hurricane Center Miami FL       EP152025
800 PM MST Tue Sep 30 2025

Octave remains a sheared tropical cyclone, with the coldest cloud
tops displaced to the south and west of the low-level center.  The
latest UW-CIMSS shear analysis indicates about 20 kt of
east-northeasterly shear over the system.  Despite this shear,
convection has persisted near the low-level center, and the cyclone
continues to exhibit well-defined banding on its southern and
western sides.  The latest subjective Dvorak intensity estimates
from TAFB and SAB are both 3.0/45 kt, while the UW-CIMSS objective
estimates have ranged from 33 to 41 kt since the previous advisory.
Based on a blend of these data, and given little change in the
overall satellite presentation during the past several hours, the
initial intensity is held at 40 kt.

Octave is estimated to be moving north-northwestward, or 340 degrees
at 6 kt.  This general motion is expected to continue tonight and
Wednesday as the cyclone moves into a weakness in the subtropical
ridge created by a disturbance to its north.  Once that disturbance
is absorbed by Octave’s circulation, a mid-level ridge is forecast
to become re-established to the north of the cyclone, steering it
westward to west-northwestward from Wednesday night through
Saturday.  By 120 hours, Octave is expected to slow considerably and
turn eastward as a longwave trough approaches from the northwest and
the subtropical ridge to its east is eroded by a developing tropical
cyclone offshore of southwestern Mexico.  The new NHC track forecast
is very similar to the previous one through 72 hours and then
slightly westward by days 4 and 5, accounting for a westward shift
in the latest guidance.  The forecast lies near the middle of the
guidance envelope, close to the GDMI aid through 72 hours, and
roughly midway between the prior track and GDMI aid beyond that
time.

Octave will remain over warm waters and within a moist environment
for the next several days.  However, moderate to strong
east-northeasterly vertical wind shear is expected to hinder
significant intensification.  Some slight strengthening is possible
tonight, followed by little change in strength during the next
couple of days.  Modest intensification is forecast by days 3 and 4
as the shear is expected to relax somewhat while the cyclone remains
over warm waters.  By day 5, slight weakening is anticipated as
Octave moves into a drier mid-level environment and over cooler
waters near 26C.  Confidence in the intensity forecast remains low
beyond day 3 due to considerable spread among the guidance.  The
official forecast is closest to the ECMWF-based SHIPS guidance and
is very similar to the previous advisory.


FORECAST POSITIONS AND MAX WINDS

INIT  01/0300Z 10.8N 114.4W   40 KT  45 MPH
12H  01/1200Z 11.6N 114.5W   45 KT  50 MPH
24H  02/0000Z 12.5N 115.2W   45 KT  50 MPH
36H  02/1200Z 13.0N 116.4W   45 KT  50 MPH
48H  03/0000Z 13.5N 117.6W   45 KT  50 MPH
60H  03/1200Z 13.9N 119.0W   45 KT  50 MPH
72H  04/0000Z 14.4N 120.5W   50 KT  60 MPH
96H  05/0000Z 15.0N 121.9W   55 KT  65 MPH
120H  06/0000Z 15.8N 121.5W   50 KT  60 MPH

$$
Forecaster Jelsema (CPHC)

pocketbox

全球热带气旋监测公报
预报：葛畅、曹越男  签发：吕心艳  2025 年 10 月 01 日 18 时
“奥克塔夫”向北偏西方向移动

时        间:   1日14时（北京时，下同）

海        域:    东北太平洋

命        名:    “奥克塔夫”，OCTAVE

中心位置:    西经114.6度，北纬10.9度

强度等级:    热带风暴

最大风力:    10级，25米/秒，相当于我国的强热带风暴级

中心气压:    1001百帕

参考位置:    距离墨西哥南下加利福尼亚州圣卢卡斯角南偏西方向约1420公里

变化过程:    过去12小时，“奥克塔夫”强度由8级增强至10级

预报结论:   “奥克塔夫”将以每小时10公里左右的速度向北偏西方向移动，强度变化不大或缓慢加强。



图1 卫星红外监测图像（北京时间2025年10月1日14时00分）

ygsj24

000
WTPZ45 KNHC 010853
TCDEP5

Tropical Storm Octave Discussion Number   5
NWS National Hurricane Center Miami FL       EP152025
200 AM MST Wed Oct 01 2025

The satellite presentation of Octave has improved during the past
several hours, with a well-defined curved band now wrapping more
than halfway around the low-level center.  This improvement in
structure appears to be due to a decrease in vertical wind shear,
which has lessened to around 16 kt according to the latest UW-CIMSS
analysis.  The most recent subjective Dvorak intensity estimates
from TAFB and SAB also indicate a stronger system, both coming in
at 3.5/55 kt, while the UW-CIMSS objective estimates are lower,
ranging between 33 and 40 kt since the previous advisory.  Based on
a blend of these data, and considering the improved satellite
presentation, the initial intensity has been raised to 50 kt for
this advisory, which may be conservative.

Octave is estimated to be moving north-northwestward, or 335 degrees
at 6 kt.  This general motion is expected to continue today as the
cyclone moves into a weakness in the subtropical ridge created by a
disturbance to its north.  Once that disturbance is absorbed by
Octave’s circulation, a mid-level ridge is forecast to become
re-established to the north of the cyclone, steering it westward to
west-northwestward from tonight through Saturday.  By 120 hours,
Octave is expected to slow considerably and turn eastward as a
longwave trough approaches from the northwest and the subtropical
ridge to its east is eroded by a developing tropical cyclone
offshore of southwestern Mexico.  The new NHC track forecast has
been shifted west of the previous one to account for the delay in
the cyclone turning toward the north-northwest and to better match
the latest guidance trends.  The forecast lies near the middle of
the guidance envelope and is close to a blend of the GDMI, FSSE,
TVCE, and HCCA track aids.

Octave will remain over warm water and within a moist environment
for the next several days.  However, vertical wind shear is forecast
to fluctuate between moderate and strong levels, which should hinder
significant intensification.  Some additional strengthening is
possible today, followed by little change in intensity over the next
few days.  Modest intensification could occur by days 4 and 5 as the
shear relaxes, although sea surface temperatures will be slightly
cooler and the mid-level environment less moist by that time.
Confidence in the intensity forecast remains low due to considerable
spread among the guidance.  The official forecast has been adjusted
higher to account for the cyclone’s improved structure and is most
closely aligned with the SHIPS and LGEM intensity aids.


FORECAST POSITIONS AND MAX WINDS

INIT  01/0900Z 11.1N 114.8W   50 KT  60 MPH
12H  01/1800Z 11.8N 115.2W   55 KT  65 MPH
24H  02/0600Z 12.5N 116.2W   55 KT  65 MPH
36H  02/1800Z 13.0N 117.4W   55 KT  65 MPH
48H  03/0600Z 13.4N 118.6W   55 KT  65 MPH
60H  03/1800Z 13.8N 120.1W   55 KT  65 MPH
72H  04/0600Z 14.3N 121.2W   55 KT  65 MPH
96H  05/0600Z 15.3N 122.4W   60 KT  70 MPH
120H  06/0600Z 16.0N 121.4W   60 KT  70 MPH

$$
Forecaster Jelsema (CPHC)

pocketbox

WTPZ45 KNHC 011452
TCDEP5

Tropical Storm Octave Discussion Number   6
NWS National Hurricane Center Miami FL       EP152025
800 AM PDT Wed Oct 01 2025

Octave's cloud pattern has changed little in organization over the
past few hours.  A convective band wraps around the southern and
eastern portion of the circulation with a banding feature also
noted over the western semicircle.  The advisory intensity is set
at 55 kt in agreement with a subjective Dvorak estimate from TAFB.  
Objective Dvorak and microwave estimates from UW-CIMSS are a little
lower than that value.

The cyclone is moving generally northwestward, or around 325/7 kt.  
A west-northwestward track is likely during the next day or so,
along the southern side of a subtropical high pressure area. Later
in the forecast period, a turn to the north into a weakness in the
subtropical ridge is expected.  Around day 5, Octave is forecast to
turn eastward in response to a trough off the California coast.  The
official forecast is close to the latest track model consensus.

The system should remain over marginally warm waters and in a moist
mid- to low-level environment for the next several days.  Easterly
vertical wind shear could relax somewhat in 2-3 days, which would
allow for some strengthening, and the system could eventually become
a hurricane.  However, the small size of the cyclone suggests that
it could also be more responsive to less conducive conditions in the
future environment.  The official intensity forecast is conservative
and lies more or less in the middle to upper portion of the model
guidance, which continues to show considerable spread.


FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 11.6N 115.7W   55 KT  65 MPH
12H  02/0000Z 12.1N 116.3W   55 KT  65 MPH
24H  02/1200Z 12.6N 117.3W   55 KT  65 MPH
36H  03/0000Z 13.1N 118.5W   55 KT  65 MPH
48H  03/1200Z 13.7N 120.0W   60 KT  70 MPH
60H  04/0000Z 14.2N 121.1W   60 KT  70 MPH
72H  04/1200Z 14.9N 122.6W   60 KT  70 MPH
96H  05/1200Z 15.9N 123.6W   60 KT  70 MPH
120H  06/1200Z 16.5N 123.0W   50 KT  60 MPH

$$
Forecaster Pasch

ygsj24

000
WTPZ45 KNHC 012043
TCDEP5

Tropical Storm Octave Discussion Number   7
NWS National Hurricane Center Miami FL       EP152025
200 PM PDT Wed Oct 01 2025

In terms of organization, the storm has been holding fairly steady
since earlier today.  Deep convection is strongest over the
southern portion of the circulation with tops to around -70 deg C
with limited banding features at this time.  Upper-level outflow is
fairly well-defined over the western semicircle and limited
elsewhere, while the system is being affected by some easterly
vertical wind shear.  The current intensity estimate is held at 55
kt, in agreement with a subjective Dvorak estimate from TAFB and
close to an AI-objective Dvorak estimate from UW-CIMSS.

Octave continues to move on a generally northwestward track at
about 305/7 kt.  A west-northwestward track is likely over the
next day or so, while the cyclone is steered by the flow on the
southern side of a weak subtropical high pressure area.  In the
latter part of the forecast period, a weakness in the subtropical
ridge should induce a turn toward the north.  Around the end of the
period, the system is forecast to turn eastward due to the
influence of a trough off the California coast and a larger
developing tropical cyclone off the southwest coast of Mexico.  The
official track forecast is close to the latest dynamical model
consensus, TVCN.

Moderate to strong easterly vertical wind shear should continue to
affect Octave for the next couple of days while the system
traverses marginally warm SSTs.  The shear could relax somewhat by
72 hours, allowing for some strengthening later in the forecast
period.  However, the relatively small size of the system's
circulation probably makes it more responsive to potentially less
conducive conditions in the future environment.  Given the
uncertainties, the official forecast shows only slight
strengthening.  This is similar to the intensity model consensus,
IVCN.

FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 12.0N 116.3W   55 KT  65 MPH
12H  02/0600Z 12.4N 117.1W   55 KT  65 MPH
24H  02/1800Z 12.9N 118.2W   55 KT  65 MPH
36H  03/0600Z 13.3N 119.3W   55 KT  65 MPH
48H  03/1800Z 13.8N 120.9W   60 KT  70 MPH
60H  04/0600Z 14.4N 122.2W   60 KT  70 MPH
72H  04/1800Z 14.9N 123.4W   60 KT  70 MPH
96H  05/1800Z 15.6N 124.0W   60 KT  70 MPH
120H  06/1800Z 16.0N 122.5W   50 KT  60 MPH

$$
Forecaster Pasch

pocketbox

全球热带气旋监测公报
预报：钟晖子、张增海  签发：张玲  2025 年 10 月 02 日 10 时
“奥克塔夫”向北偏西方向移动

时        间:   2日08时（北京时，下同）

海        域:    东北太平洋

命        名:    “奥克塔夫”，OCTAVE

中心位置:    西经116.7度，北纬12.1度

强度等级:    热带风暴

最大风力:    10级，28米/秒，相当于我国的强热带风暴级

中心气压:    994百帕

参考位置:    距离墨西哥南下加利福尼亚州圣卢卡斯角西南方向约1390公里

变化过程:    过去24小时，“奥克塔夫”强度由8级增强至10级

预报结论:   “奥克塔夫”将以每小时10公里左右的速度向西北方向移动，强度变化不大或缓慢加强。



图1 卫星红外监测图像（北京时间2025年10月1日14时00分）

ygsj24

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)

pocketbox

全球热带气旋监测公报
预报：钟晖子、张增海  签发：张玲  2025 年 10 月 02 日 18 时
“奥克塔夫”向北偏西方向移动

时        间:   2日14时（北京时，下同）

海        域:    东北太平洋

命        名:    “奥克塔夫”，OCTAVE

中心位置:    西经117.5度，北纬12.0度

强度等级:    热带风暴

最大风力:    10级，28米/秒，相当于我国的强热带风暴级

中心气压:    994百帕

参考位置:    距离墨西哥南下加利福尼亚州圣卢卡斯角西南方向约1390公里

变化过程:    过去24小时，“奥克塔夫”强度由8级增强至10级

预报结论:   “奥克塔夫”将以每小时10公里左右的速度向西北方向移动，强度变化不大或缓慢加强。



图1 卫星红外监测图像（北京时间2025年10月2日14时00分）

ygsj24

000
WTPZ45 KNHC 020850
TCDEP5

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)

pocketbox

WTPZ45 KNHC 021438
TCDEP5

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