霧峰追風者

  五級颶風  
編號：01 C
名稱：Walaka

  基本資料  
擾動編號日期：2018 年 09 月 27 日 23 時
命名日期　　：2018 年 09 月 30 日 05 時
撤編日期　　：2018 年 10 月 00 日 00 時
登陸地點　　：暫無

  巔峰時期資料  
近中心最強風速 ：140 kt
海平面最低氣壓 ：920 百帕

  過去路徑圖  

  擾動編號資料  
97C.INVEST.25kts-1008mb-12.3N-145.4W

CPHC : 30%

1. Showers and thunderstorms associated with a surface trough located
about 990 miles southeast of Hilo, Hawaii are becoming slightly
more organized, but continue to flare up and down in coverage and
intensity. A low-level circulation center is now apparent on visible
satellite imagery. Environmental conditions remain conducive for
gradual development of this system over the next few days as it
moves westward across the central Pacific.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...70 percent.

以上資料來自：CPHC、颱風論壇整理製作

霧峰追風者

CPHC 展望提升至60%，數值看好發展。

1. Showers and thunderstorms associated with a low level circulation
center located about 700 miles southeast of Hilo, Hawaii continues
to become better organized. Environmental conditions remain
conducive for this system to become a tropical depression this week
while it moves west 10 to 15 mph.
* Formation chance through 48 hours...Medium...60 percent.
* Formation chance through 5 days...High...90 percent.

霧峰追風者

CPHC 展望提升至70%。

1. Showers and thunderstorms associated with a low level circulation
center located about 600 miles southeast of Hilo, Hawaii continues
to become better organized. Environmental conditions remain
conducive for this system to become a tropical depression this week
while it moves west at around 15 mph.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

周子堯@FB

JTWC 28/21Z發布TCFA，數值看好發展

1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
150 NM EITHER SIDE OF A LINE FROM 12.4N 152.1W TO 12.6N 158.9W
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 282000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.3N 153.0W. THE SYSTEM IS MOVING WESTWARD AT 15 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97C) PREVIOUSLY LOCATED
NEAR 12.4N 146.4W, IS NOW LOCATED NEAR 12.3N 153.0W, APPROXIMATELY
465 NM SOUTH-SOUTHEAST OF HILO, HAWAII. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY AND A 281843Z 89 GHZ MHS IMAGE DEPICT A BROAD LOW
LEVEL CIRCULATION WITH BROAD DEEP CONVECTION. THE UPPER LEVEL
ENVIRONMENT IS FAVORABLE, WITH LOW (5-10 KTS) VWS AND ADEQUATE UPPER
LEVEL DIVERGENCE DUE TO STRONG POLEWARD OUTFLOW. SSTS REMAIN
FAVORABLE (28-30 CELSIUS) IN THE REGION. GLOBAL MODELS GENERALLY
AGREE ON THE STORM DEVELOPING OVER THE NEXT FEW DAYS WHILE TRACKING
SLOWLY TO THE WEST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH. THIS SUPERSEDES REF A
(WTPN21 PHNC 272100).

周子堯@FB

NHC命名01C.Walaka

ZCZC HFOTWOCP ALL
TTAA00 PHFO DDHHMM

Tropical Weather Outlook
NWS Central Pacific Hurricane Center Honolulu HI
200 PM HST Sat Sep 29 2018

For the central North Pacific...between 140W and 180W:

The Central Pacific Hurricane Center is issuing advisories on
Tropical Storm Walaka, centered about 675 miles south of Honolulu,
Hawaii.

Elsewhere, no tropical cyclones are expected during the next 5
days.

Public Advisories on Tropical Storm Walaka are issued under WMO
header WTPA31 PHFO and under AWIPS header HFOTCPCP1.
Forecast Advisories on Tropical Storm Walaka are issued under WMO
header WTPA21 PHFO and under AWIPS header HFOTCMCP1.

$$
Forecaster Kino
NNNN

霧峰追風者

CPHC 21Z命名"WALAKA"，巔峰上望MH。

WTPA41 PHFO 292107
TCDCP1

Tropical Storm Walaka Discussion Number   1
NWS Central Pacific Hurricane Center Honolulu HI   CP012018
1100 AM HST Sat Sep 29 2018

The tropical disturbance passing far south of the main Hawaiian
Islands has developed persistent deep convection near the center
with a banding feature developing within the eastern and southern
quadrants. A series of SSMI and SSMIS passes between 1348 and 1716
UTC showed this structure and provided some indication of the
location of the low level circulation center. Subjective Dvorak
current intensity estimates from JTWC and SAB were constrained to
2.0/30 kt, with data T numbers coming in at 2.5/35 kt, and the
current intensity from HFO was 2.5/35 kt. These inputs support
initiating advisories for Tropical Storm Walaka, the sixth tropical
cyclone of 2018 in the Central Pacific basin and the first to form
in the basin this year.

Walaka is moving toward the west (265 degrees) at 13 kt. A westward
motion will continue for the next 36 hours or so as the system
remains south of a deep ridge. This will take Walaka well southwest
of the main Hawaiian Islands. Late Sunday through Monday night, the
cyclone will make a gradual turn toward the northwest then north as
a deep North Pacific trough digs southward and steadily erodes the
ridge. As a result, Walaka will pass very close to Johnston Island
as early as Monday night and likely sometime Tuesday. The deep
trough will stall roughly along 171W longitude on Tuesday, causing
the tropical cyclone to accelerate northward. On days four and
five, the motion becomes uncertain due to model differences in the
handling of the interaction between Walaka with the deep trough. The
track forecast follows a rather tightly clustered guidance envelope
through Tuesday, then favors the HMON, which is closer to TVCE than
the faster GFS and slower ECMWF. Due to the uncertainty in the long
term motion, interests in the Papahanaumokuakea Marine National
Monument should monitor Walaka.

Strengthening, possibly rapid, is expected through the next three
days, and Walaka is forecast to remain intense through day five.
Walaka will remain under low vertical wind shear and over SSTs of
around 29C through at least Monday, and likely into Tuesday. In this
environment, the SHIPS rapid intensification guidance for Walaka is
well above the climatological mean. The intensity forecast is close
to LGEM and ICON through the initial 48 hours and remains near the
HWRF and ICON, but below LGEM, thereafter. Walaka is forecast to
become a hurricane by Sunday, and along the forecast track,
hurricane conditions could be experienced on Johnston Island as
early as Monday night. Some weakening is indicated beyond Tuesday
due to increasing southwesterly vertical wind shear.


FORECAST POSITIONS AND MAX WINDS

INIT  29/2100Z 11.5N 159.1W   35 KT  40 MPH
12H  30/0600Z 11.5N 161.5W   45 KT  50 MPH
24H  30/1800Z 11.8N 164.2W   60 KT  70 MPH
36H  01/0600Z 12.5N 166.6W   75 KT  85 MPH
48H  01/1800Z 13.4N 168.4W   90 KT 105 MPH
72H  02/1800Z 16.5N 169.6W  110 KT 125 MPH
96H  03/1800Z 21.4N 168.5W  100 KT 115 MPH
120H  04/1800Z 27.0N 168.0W   80 KT  90 MPH

$$
Forecaster Wroe

t02436

隔壁棚的Walaka也進入RI，09Z評價90節，巔峰上望135節！

WTPA41 PHFO 010925
TCDCP1

Hurricane Walaka Discussion Number   7
NWS Central Pacific Hurricane Center Honolulu HI   CP012018
1100 PM HST Sun Sep 30 2018

Walaka is undergoing rapid intensification this evening, which is
clearly evident given the large ring of -70 to -85C cloud tops
surrounding the the well defined eye. Additionally, recent
microwave passes indicate that the organization of the system has
improved significantly, while geostationary satellite animations
show well defined outflow channels in all quadrants. The latest
intensity estimates came in at 5.0 (90 knots) from PHFO and SAB, 4.5
(77 knots) from JTWC, while the UW-CIMSS ADT was 4.2 (70 knots).
Based on the significant improvement in appearance and organization
of Walaka, the initial intensity for this advisory was increased to
90 knots. The initial motion was set at 280/10 knots.

Walaka continues to be steered westward this evening by a
subtropical ridge to the north of the system, and this motion is
expected to continue tonight. A turn toward the northwest is
expected on Monday as a deep north Pacific upper trough digs
southward in the vicinity of 30N 170W. A turn toward the north is
then expected on Tuesday, with Walaka continuing on this course
through Tuesday night with an increase in forward speed. The
tropical cyclone should then make a turn toward the north-northeast
Wednesday and Wednesday night as it begins to feel the influence of
the deep upper level trough. The track guidance then suggests a
shift back toward the north with a decrease in forward speed
Thursday through Friday as Walaka interacts with the deep upper
level trough. The official forecast was nudged slightly to the left
through 48 hours, then slightly to the right beyond 48 hours, and
is very close to the HCCA, TVCN, and GFEX consensus guidance.

The environment surrounding Walaka remains very conducive for
additional intensification through 48 hours. The tropical cyclone
will remain within a deep moist airmass, with vertical wind shear
forecast to remain around 10 knots or less through 48 hours, and
sea surface temperatures holding in the 84 to 86 Fahrenheit range
during this time. As a result, additional rapid intensification is
expected tonight and Monday, with the cyclone then forecast to level
off just below category 5 status Tuesday and Tuesday night. Given
the environment surrounding the system, intensification to a
category 5 storm is not out of the question, although none of the
intensity guidance explicitly indicate this at this time.
Additionally, Walaka will likely undergo eyewall replacement cycles
which will lead to some fluctuation in intensity. Beyond 48 hours,
vertical wind shear will steadily increase as Walaka approaches and
begins to interact with the deep upper level trough over the
north-central Pacific, with sea surface temperatures dropping off as
well. The intensity forecast shows a gradual weakening by 72 hours,
with rapid weakening then expected beyond 72 hours through the end
of the forecast period. The official intensity forecast has been
increased from the previous advisory and is in line with the high
end of the intensity guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  01/0900Z 11.9N 167.5W   90 KT 105 MPH
12H  01/1800Z 12.5N 168.7W  115 KT 130 MPH
24H  02/0600Z 13.5N 169.9W  130 KT 150 MPH
36H  02/1800Z 15.1N 170.5W  135 KT 155 MPH
48H  03/0600Z 17.2N 170.5W  135 KT 155 MPH
72H  04/0600Z 23.3N 168.1W  115 KT 130 MPH
96H  05/0600Z 28.5N 167.5W   75 KT  85 MPH
120H  06/0600Z 31.0N 166.0W   60 KT  70 MPH

$$
Forecaster Jelsema

t02436

15Z評價110節，CPHC正式上望C5！

WTPA41 PHFO 011504
TCDCP1

Hurricane Walaka Discussion Number   8
NWS Central Pacific Hurricane Center Honolulu HI   CP012018
500 AM HST Mon Oct 01 2018

The satellite presentation of Walaka has improved significantly
overnight as the cyclone continues to rapidly intensify. The well
defined eye is surrounded by a large ring of -70 to -85C cloud
tops, and continues to show excellent outflow in all quadrants as
evident in geostationary satellite animations. Additionally, large
deep convective banding features are present on both the east and
west side of Walaka early this morning. The latest intensity
estimates came in at 5.5 (102 knots) from PHFO, SAB, and JTWC, while
the UW-CIMSS ADT was 5.4 (100 knots). As of 01/14Z, raw DT numbers
are as high as 7.0 (140 knots), but need to be held down
due to intensification constraints. Based on this data along with
the continued improvement in the appearance and organization, the
initial intensity of Walaka for this advisory was increased to 110
knots, making it 5 knots short of category 4 status. The initial
motion was set at 295/09 knots.

Walaka is beginning to round the southwest periphery of a large
subtropical ridge this morning and is currently moving toward the
west-northwest. A turn toward the northwest is expected later today
as a deep north Pacific upper trough digs southward in the vicinity
of 30N 170W and further erodes the western end of the subtropical
ridge. A turn toward the north is then expected on Tuesday, with
Walaka continuing on this course through Tuesday night with an
increase in forward speed. The tropical cyclone should then make a
turn toward the north-northeast Wednesday and Wednesday night as it
begins to feel the influence of the deep upper level trough. The
track guidance then suggests a shift back toward the north with a
decrease in forward speed Thursday through Friday as Walaka
interacts with the deep upper level trough, with a turn back toward
the northeast expected Friday night. The official track forecast
was changed very little from the previous advisory and remains
in close proximity to the tightly clustered HCCA, TVCN, and GFEX
consensus guidance.

The environment surrounding Walaka remains very conducive for
additional intensification during the next 36 hours and possibly
even a bit longer. Today through Tuesday, the tropical cyclone will
remain within a deep moist airmass, with vertical wind shear
forecast to remain around 10 knots, and sea surface temperatures
holding in the 84 to 86 Fahrenheit range. As a result, additional
rapid intensification is expected today into tonight, with the
cyclone then forecast to level off late tonight through Tuesday
night. Given the environment surrounding the system, the intensity
forecast brings Walaka up to category 5 intensity tonight, and is
slightly above the intensity guidance which doesn't explicitly
indicate Walaka will reach category 5 intensity. There is the
potential that Walaka could intensify even more than currently
forecast, but due to eyewall replacement cycles likely leading to
some fluctuation in intensity, the forecast was held nearly steady
from late tonight through Tuesday night. Vertical wind shear is
expected to steadily increase Wednesday and Wednesday night as
Walaka approaches and begins to interact with the deep upper level
trough over the north-central Pacific, with sea surface temperatures
dropping off during this time as well. The intensity forecast
calls for rapid weakening beginning beyond 48 hours, with this
weakening trend expected to continue through the end of the forecast
period. The official intensity forecast has been increased from the
previous advisory and is slightly higher than all intensity guidance
through 36 hours, then falls more closely in line with a blend of
the statistical and dynamical guidance for forecast hour 72 through
120.


FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 12.3N 168.3W  110 KT 125 MPH
12H  02/0000Z 13.1N 169.4W  130 KT 150 MPH
24H  02/1200Z 14.5N 170.4W  140 KT 160 MPH
36H  03/0000Z 16.4N 170.7W  140 KT 160 MPH
48H  03/1200Z 18.9N 170.1W  135 KT 155 MPH
72H  04/1200Z 25.0N 167.5W  100 KT 115 MPH
96H  05/1200Z 29.5N 167.0W   75 KT  85 MPH
120H  06/1200Z 33.0N 164.0W   60 KT  70 MPH

$$
Forecaster Jelsema