东太平洋热带风暴“奥克塔夫”(15E.Octave)

Lupiter

98E INVEST 250929 0000 10.4N 109.8W EPAC 15 1009

---

1. Well South of the Baja California Peninsula:
An area of disturbed weather associated with a tropical wave located
several hundred miles offshore of southwest Mexico is beginning to
become better organized. Environmental conditions are expected to be
conducive for additional development during the next few days and a
tropical cyclone is likely to form by the middle of the week. The
system is forecast to drift westward for the next day or two, then
turn west-northwestward after that time.   
* Formation chance through 48 hours...medium..50 percent.
* Formation chance through 7 days...high...80 percent.

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ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Sep 28 2025

For the eastern and central North Pacific east of 180 longitude:

Active Systems:
The National Hurricane Center has issued the last advisory on
Post-Tropical Cyclone Narda, located well to the west of the
southern tip of the Baja California Peninsula.

1. Well South of the Baja California Peninsula (EP98):
An area of disturbed weather associated with a tropical wave located
several hundred miles offshore of southwest Mexico has become better
organized. Environmental conditions appear conducive for further
development, and a tropical depression is likely to form in the next
day or two. The system is forecast to drift westward into Tuesday,
then turn west-northwestward thereafter.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...90 percent.



2. Near the Southwest Coast of Mexico:
An area of low pressure is expected to develop off the southwest
coast of Mexico near the end of the week. Environmental conditions
are forecast to be conducive for gradual development of the system
next weekend.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

Forecaster Gibbs

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WTPN21 PHNC 290800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98E)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
105 NM EITHER SIDE OF A LINE FROM 10.4N 110.9W TO 10.8N 115.2W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 23 TO 28 KNOTS. METSAT
IMAGERY AT 290600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.4N 110.9W. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 09
KNOTS.
2. REMARKS: AN AREA OF CONVECTION (INVEST 98E) IS LOCATED NEAR 10.4N
110.9W, APPROXIMATELY 639 NM SOUTHWEST OF MANZANILLO, MEXICO. ANIMATED
ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW
LEVEL CIRCULATION CENTER WITH FLARING CONVECTION BUILDING OVER THE
CENTER. ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE AREA FOR
DEVELOPMENT WITH FAIR DIFFLUENCE ALOFT, LOW TO MODERATE (15-20KT)
VERTICAL WIND SHEAR, AND WARM (27-29C) SEA SURFACE TEMPERATURES. GLOBAL
MODELS ARE IN AGREEMENT THAT THE INVEST WILL TRACK WESTWARD OVER THE
NEXT 24-48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO
28 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1001 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
300800Z.
//
NNNN

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ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Sep 29 2025

For the eastern and central North Pacific east of 180 longitude:

1. Well South of the Baja California Peninsula (EP98):
An area of disturbed weather associated with a sharp trough of low
pressure is located several hundred miles offshore of southwest
Mexico and continues to show signs of organization, with earlier
satellite wind data indicating the surface circulation was better
defined than earlier. Environmental conditions appear conducive for
further development, and a tropical depression is likely to form in
the next day or so. The system is forecast to drift westward into
Tuesday, then turn west-northwestward thereafter, remaining over the
open waters of the central to western part of the Eastern Pacific.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.



2. Just South of of the Baja California Peninsula:
A small area of low pressure located a few hundred miles west of
Manzanillo, Mexico is producing a small, but concentrated area of
showers and thunderstorms. Earlier satellite wind data also
indicated there was a weak surface circulation. Some additional
development is possible over the next day or two before it merges
with a larger area of disturbed weather, (EP98), to its southwest.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

3. Near the Southwest Coast of Mexico:
Another area of low pressure is expected to develop off the
southwest coast of Mexico near the end of the week. Environmental
conditions are forecast to be conducive for additional development
of the system thereafter and a tropical depression could form by the
early portion of next week as the system moves generally
west-northwestward, parallel to the coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.

Forecaster Papin

ygsj24

000
ABPZ20 KNHC 291747
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Sep 29 2025

For the eastern and central North Pacific east of 180 longitude:

Well South of the Baja California Peninsula (EP98):
A small area of low pressure has developed within a broader area of
disturbed weather located several hundred miles offshore of the
southwest coast of Mexico. First light visible satellite imagery and
recent scatterometer imagery suggests a well-defined circulation is
developing. In addition, convection continues to show signs of
organization. If these trends continue, a tropical depression is
likely to form as soon as this afternoon. The system is forecast to
drift westward over the next day or so, then turn west-northwestward
or northwestward thereafter, remaining over the open waters of the
central to western part of the Eastern Pacific.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

South of of the Baja California Peninsula:
Shower and thunderstorm activity has not become any better organized
in association with a small area of low pressure located a few
hundred miles west-southwest of Manzanillo, Mexico. Additional
development of this system appears unlikely over the next day or two
before it is absorbed by a larger area of disturbed weather (EP98)
to its southwest.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

Near the Southwest Coast of Mexico:
Another area of low pressure is expected to develop off the
southwest coast of Mexico near the end of the week. Environmental
conditions are forecast to be conducive for additional development
of the system thereafter and a tropical depression could form by the
early portion of next week as the system moves generally
west-northwestward, near the coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Papin

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ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Mon Sep 29 2025

For the eastern and central North Pacific east of 180 longitude:

1. Well South of the Baja California Peninsula (EP98):
Showers and thunderstorms associated with a small area of low
pressure far to the south of the southern tip of the Baja California
Peninsula have increased some during the past several hours.
Environmental conditions remain favorable for development of this
system, and a tropical depression is likely to form during the next
day or so as the low drifts slowly northwestward well off the coast
of Mexico.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.



2. South of the Baja California Peninsula:
Showers and thunderstorms associated with a small area of low
pressure located several hundred miles south of the southern tip of
the Baja California Peninsula have decreased considerably during the
past few hours.  Development of this system is no longer expected.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...near 0 percent.

3. Near the Southwest Coast of Mexico:
An area of low pressure is expected to develop off the coast of
southwestern Mexico late this week.  Environmental conditions are
forecast to be conducive for additional development of the system
thereafter, and a tropical depression could form by early next week
as the system moves generally west-northwestward, just offshore of
the coast of southwestern Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...60 percent.

Forecaster Jelsema

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WTPZ45 KNHC 300833
TCDEP5

Tropical Depression Fifteen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP152025
200 AM MST Tue Sep 30 2025

The area of low pressure located well south-southwest of the
southern tip of the Baja California Peninsula has become better
organized over the past several hours.  Satellite imagery shows
persistent convection and the development of a well-defined curved
band.  In addition, a recent 0355 UTC Metop-B ASCAT pass revealed a
well-defined center along with a couple of 30-kt wind barbs.  As a
result, the system has met the criteria to be classified as a
tropical cyclone.  The latest subjective Dvorak intensity estimates
from TAFB and SAB were 2.0/30 kt and 2.5/35 kt, respectively.  Based
on a blend of these data, advisories are being initiated on Tropical
Depression Fifteen-E with an initial intensity of 30 kt.

Fifteen-E is estimated to be moving slowly west-northwestward, or
295 degrees at 4 kt.  This west-northwestward motion is expected to
continue today, along the southern periphery of a low- to mid-level
ridge situated north of the cyclone.  A turn toward the
north-northwest is expected later today as a weak low to the north
of Fifteen-E erodes the ridge, with this general motion likely
continuing through around 48 hours.  Thereafter, a building
mid-level ridge to the north of the cyclone is forecast to steer
Fifteen-E west-northwestward beyond 48 hours through the end of the
forecast period.  The official track forecast lies near the middle
of the guidance envelope and is closest to the TVCE consensus aid.

Fifteen-E will remain over warm waters and within a moist
environment during the next several days, but moderate to strong
east-northeasterly vertical wind shear is expected to hinder
significant intensification.  Some slight strengthening is forecast
during the next 12 hours, and Fifteen-E is expected to reach
tropical storm strength later today.  Little change in strength is
anticipated through much of the forecast period, followed by some
modest strengthening on days 4 and 5 as the shear is forecast to
relax slightly.  The intensity forecast is of low confidence and
remains near the middle of the guidance envelope, closest to a
blend of the SHIPS and HCCA intensity aids.


FORECAST POSITIONS AND MAX WINDS

INIT  30/0900Z  9.4N 113.2W   30 KT  35 MPH
12H  30/1800Z  9.8N 113.9W   35 KT  40 MPH
24H  01/0600Z 10.8N 114.2W   35 KT  40 MPH
36H  01/1800Z 11.8N 114.4W   35 KT  40 MPH
48H  02/0600Z 12.6N 114.9W   35 KT  40 MPH
60H  02/1800Z 13.1N 116.1W   35 KT  40 MPH
72H  03/0600Z 13.5N 117.4W   35 KT  40 MPH
96H  04/0600Z 14.2N 119.8W   40 KT  45 MPH
120H  05/0600Z 15.0N 120.6W   45 KT  50 MPH

$$
Forecaster Jelsema (CPHC)

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WTPZ45 KNHC 301444
TCDEP5

Tropical Storm Octave Discussion Number   2
NWS National Hurricane Center Miami FL       EP152025
800 AM MST Tue Sep 30 2025

The convective structure of the depression has continued to improve
this morning, with cold cloud tops (-80C CMG) developing over the
surface center, and a deep convective curved band located in the
east semicircle of the cyclone.  Subjective Dvorak intensity
estimates from TAFB and SAB are T2.0 and T3.0, and the UW-CIMSS
objective intensity analyses range from 34-39 kt.  Based on a blend
of these data and the cyclone's improved satellite presentation, the
initial intensity is raised to 35 kt, upgrading Tropical Depression
Fifteen-E to Tropical Storm Octave.

Although Octave should remain over warm oceanic surface
temperatures, and move within a surrounding environment with ample
low- to mid-level moisture, moderate deep-layer east-northeasterly
shear is expected to hamper significant development.  Accordingly,
the forecast reflects little change in strength through Thursday.  
Afterward, the statistical Decay-SHIPS intensity guidance and the
global models indicate that the shear will diminish some, allowing
for some additional intensification through day 5, and the intensity
forecast follows suit.

Octave's initial motion is estimated to be northwestward, or
325/4 kt.  The cyclone is forecast to turn north-northwestward to
northward later today in response to a mid-tropospheric cut-off
low drifting southward toward Octave.  Beyond the 60 hour period,
model guidance indicates that a subtropical ridge will build to the
north of the cyclone and induce a west-northwestward motion through
Saturday, while the cut-off mentioned above weakens and ultimately
dissipates.  By day 5, the global models agree that Octave will
slow in forward speed and gradually turn toward the northwest and
north-northwest, while the ridge to the north of the cyclone erodes.
The NHC forecast lies close to the various consensus aids and has
been shifted a bit to the right of the previous forecast after 36
hours.


FORECAST POSITIONS AND MAX WINDS

INIT  30/1500Z  9.9N 113.5W   35 KT  40 MPH
12H  01/0000Z 10.4N 113.7W   35 KT  40 MPH
24H  01/1200Z 11.3N 114.0W   40 KT  45 MPH
36H  02/0000Z 12.3N 114.3W   40 KT  45 MPH
48H  02/1200Z 12.9N 115.2W   40 KT  45 MPH
60H  03/0000Z 13.4N 116.3W   40 KT  45 MPH
72H  03/1200Z 13.8N 117.5W   45 KT  50 MPH
96H  04/1200Z 14.6N 119.5W   45 KT  50 MPH
120H  05/1200Z 15.6N 119.8W   50 KT  60 MPH

$$
Forecaster Roberts

ygsj24

000
WTPZ45 KNHC 302044
TCDEP5

Tropical Storm Octave Discussion Number   3
NWS National Hurricane Center Miami FL       EP152025
200 PM MST Tue Sep 30 2025

Octave continues to become a little better organized this afternoon,
with curved bands forming primarily along the southwestern side of
the small cyclone. The wind field appears so small that
scatterometer data largely missed the small circulation in the
narrow 100 n mi gap between passes. The latest subjective Dvorak
intensity estimates were T3.0/45 kt from SAB, and T2.5/35 kt from
TAFB. The initial intensity is raised to 40 kt this advisory, a
blend of the two estimates, and near the latest ADT estimate of
T2.8/41 kt and D-PRINT estimate of 40 kt.

Octave is still moving northwestward, with the latest motion
estimated at 320/4 kt. A turn more to the north-northwest is
anticipated over the next day or so as Octave interacts with the
remnant low-level vorticity of another small disturbance that is
passing the system by to the north. Most of the guidance shows
Octave quickly absorbing the weaker system, and after that is
complete, low to mid-level ridging builds back in, resulting in the
cyclone turning back west-northwestward from 36-72 h. Towards the
end of the forecast, steering currents are expected to collapse as a
longwave trough erodes the mid-level ridging and low-level monsoonal
flow becomes more established to the east of Octave. Compared to the
previous cycle, the track guidance has trended westward, and the NHC
track forecast has been shifted a little farther west early on, but
more substantially by the end of the forecast period, though it
remains east of the latest HCCA and Google DeepMind ensemble mean
(GDMI).

The tropical storm has been able to intensify a little today despite
being under 20-25 kt of east-northeasterly vertical wind shear. This
shear is expected to persist for the next 36-48 hours, and thus only
a slight bit of additional intensification is expected tonight
followed by a pause in strengthening. After 60 h, Shear is expected
to decrease to 10-15 kt, and how much the storm is able to intensify
will be related to its structural characteristics. Octave is
expected to remain a small tropical cyclone, so its possible it
could be prone to more rapid intensity changes (both up or down)
than shown here. For now, the intensity was bumped up a little
towards the end of the forecast period, but remains much lower than
some of the more aggressive hurricane-regional model guidance (HWRF,
HAFS-A) which develop an inner core with Octave much sooner than the
remainder of the guidance. The NHC intensity forecast is closest to
the HFIP corrected consensus approach (HCCA).


FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 10.2N 113.9W   40 KT  45 MPH
12H  01/0600Z 10.8N 114.0W   45 KT  50 MPH
24H  01/1800Z 12.0N 114.5W   45 KT  50 MPH
36H  02/0600Z 12.6N 115.3W   45 KT  50 MPH
48H  02/1800Z 13.0N 116.6W   45 KT  50 MPH
60H  03/0600Z 13.6N 117.9W   45 KT  50 MPH
72H  03/1800Z 14.0N 119.3W   50 KT  60 MPH
96H  04/1800Z 14.5N 120.7W   55 KT  65 MPH
120H  05/1800Z 15.5N 121.0W   55 KT  65 MPH

$$
Forecaster Papin

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全球热带气旋监测公报
预报：曹越男  签发：吕心艳  2025 年 10 月 01 日 10 时
东北太平洋热带风暴“奥克塔夫”生成

时        间:   1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114.2度，北纬10.5度

强度等级:    热带风暴

最大风力:    8级，20米/秒，相当于我国的热带风暴级

中心气压:    1002百帕

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1452公里

变化过程:    “奥克塔夫”于昨天夜间在东北太平洋生成

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，强度逐渐加强。



图1 卫星红外监测图像（北京时间2025年10月1日08时00分）