霧峰追風者

  二級熱帶氣旋  
編號：03 U ( 96 S )
名稱 : Dahlia

  基本資料  
擾動編號日期：2017 年 11 月 23 日 22 時
升格熱低日期：2017 年 11 月 25 日 20 時
命名日期　　：2017 年 11 月 29 日 20 時
JTWC升格日期:2017 年 11 月 30 日 08 時
撤編日期　　：2017 年 12 月 08 日 01 時
登陸地點　　：無

  巔峰時期資料  
澳洲氣象局(BoM)：50 kt ( TS )
印尼雅加達氣象局(BMKG)：50 kt
聯合颱風警報中心(JTWC)：50 kts ( TS )
海平面最低氣壓：987 百帕

  過去路徑圖  

  擾動編號資料  
96S.INVEST.20kts.1007mb.4.3S.93.7E


以上資料來自：BoM、BMKG、JTWC、颱風論壇整理製作

霧峰追風者

緩慢移動一天，結果中心裸露，發展不如預期。

IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1808 UTC 02/12/2017
Name: Tropical Cyclone Dahlia
Identifier: 03U
Data At: 1800 UTC
Latitude: 11.5S
Longitude: 111.8E
Location Accuracy: within 30 nm [55 km]
Movement Towards: southeast [135 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 35 knots [65 km/h]
Maximum 3-Second Wind Gust: 50 knots [95 km/h]
Central Pressure: 998 hPa
Radius of 34-knot winds NE quadrant: 70 nm [130 km]
Radius of 34-knot winds SE quadrant: 30 nm [55 km]
Radius of 34-knot winds SW quadrant: 30 nm [55 km]
Radius of 34-knot winds NW quadrant: 70 nm [130 km]
Radius of 48-knot winds NE quadrant:   
Radius of 48-knot winds SE quadrant:   
Radius of 48-knot winds SW quadrant:   
Radius of 48-knot winds NW quadrant:   
Radius of 64-knot winds:   
Radius of Maximum Winds: 20 nm [35 km]
Dvorak Intensity Code: T2.0/3.0/W0.5/24HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 180 nm [335 km]
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
[UTC]        : degrees     :      nm  [km]: knots[km/h]: hPa
+06:  03/0000: 12.0S 111.8E:     040 [075]:  040  [075]:  992
+12:  03/0600: 12.9S 111.5E:     065 [120]:  045  [085]:  992
+18:  03/1200: 13.9S 111.3E:     085 [155]:  045  [085]:  992
+24:  03/1800: 15.1S 111.0E:     100 [185]:  040  [075]:  992
+36:  04/0600: 17.0S 110.5E:     105 [195]:  030  [055]:  997
+48:  04/1800: 17.8S 110.6E:     125 [230]:  030  [055]:  998
+60:  05/0600: 18.1S 111.0E:     140 [260]:  025  [045]: 1001
+72:  05/1800: 17.9S 111.7E:     160 [295]:  020  [035]: 1003
+96:  06/1800: 17.4S 112.9E:     200 [370]:  020  [035]: 1003
+120: 07/1800: 16.9S 112.8E:     290 [535]:  020  [035]: 1003
REMARKS:
TC Dahlia has been located with moderate confidence by microwave imagery.

Intensity of Dahlia has decreased over the past 12 hours. The strong deep layer
shear [above 20 knots] has hindered the system. The deep convection has weakened
and the low level centre has become exposed.

The intensity of the system has been reduced to a 35 knots. Dvorak analysis of
FT=2.0 and CI=3.0 is based on PAT and MET and is consistent with ADT.

The system is likely to track southwards under the influence of a steering
anti-cyclone that builds to the east. Along this path Dahlia may experience less
environmental shear and has the chance to develop during Sunday. Though this
potential window for development is complicated as the remnant circulation of TC
Cempaka to the southwest of Dahlia and another vortex to the southeast compete
for vorticity. The interaction of these three systems will affect the future
motion and development of TC Dahlia.

Some models do not resolve these weaker circulations and these tend to move
Dahlia faster than the forecast track and intensify the system. This scenario is
increasingly less likely and the forecast track reflects a slower motion and no
longer reaches Category 3.

On Monday the system weakens as it encounters cooler water south of 17S. Shear
across the system will also increase and the system is unlikely to be able to
maintain TC intensity by Tuesday.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 02/1930 UTC by Perth TCWC.

Meow

查帕卡仍在西南側，繼續干擾Dahlia發展。

霧峰追風者

BoM 上望三級熱帶氣旋，逐漸南下。

IDW27700
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0143 UTC 01/12/2017
Name: Tropical Cyclone Dahlia
Identifier: 03U
Data At: 0000 UTC
Latitude: 9.7S
Longitude: 109.4E
Location Accuracy: within 25 nm [45 km]
Movement Towards: east southeast [120 deg]
Speed of Movement: 8 knots [16 km/h]
Maximum 10-Minute Wind: 45 knots [85 km/h]
Maximum 3-Second Wind Gust: 65 knots [120 km/h]
Central Pressure: 992 hPa
Radius of 34-knot winds NE quadrant: 90 nm [165 km]
Radius of 34-knot winds SE quadrant: 50 nm [95 km]
Radius of 34-knot winds SW quadrant: 60 nm [110 km]
Radius of 34-knot winds NW quadrant: 90 nm [165 km]
Radius of 48-knot winds NE quadrant:   
Radius of 48-knot winds SE quadrant:   
Radius of 48-knot winds SW quadrant:   
Radius of 48-knot winds NW quadrant:   
Radius of 64-knot winds:   
Radius of Maximum Winds: 25 nm [45 km]
Dvorak Intensity Code: T3.0/3.0/D0.5/24HRS STT:S0.0/6HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 150 nm [280 km]
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
[UTC]        : degrees     :      nm  [km]: knots[km/h]: hPa
+06:  01/0600: 10.2S 109.9E:     035 [070]:  045  [085]:  991
+12:  01/1200: 10.8S 110.3E:     050 [090]:  050  [095]:  987
+18:  01/1800: 11.5S 110.2E:     060 [115]:  060  [110]:  980
+24:  02/0000: 12.1S 110.0E:     075 [135]:  065  [120]:  977
+36:  02/1200: 13.3S 109.5E:     095 [175]:  065  [120]:  976
+48:  03/0000: 14.5S 109.0E:     115 [210]:  055  [100]:  984
+60:  03/1200: 16.0S 109.1E:     130 [245]:  045  [085]:  991
+72:  04/0000: 17.6S 109.2E:     150 [280]:  040  [075]:  994
+96:  05/0000: 19.7S 110.2E:     195 [365]:  030  [055]:  998
+120: 06/0000: 21.3S 111.9E:     285 [525]:  025  [045]: 1002
REMARKS:
TC Dahlia has continued to move east over the last few hours. It now appears the
low level circulation centre has moved further under the deep convection after
being exposed to the east of the deepest convection. This is consistent with a
decrease in easterly wind shear.

Dvorak analysis: FT/CI=3.0 based on a time-averaged shear pattern and MET,
although the latest imagery is showing indications that it is now closer to 3.5.


Models are consistent with a turn to the south during Saturday.

Further development is expected as the shear eases and forecast intensity has
been increased to category 3 during Saturday. On Sunday model guidance suggests
a weakening trend and this becomes more obvious by Monday as the system
encounters cooler water south of 18S and dry air wraps around from the west.
Gales may persist to the southwest as the system interacts with the synoptic
SE'ly flow associated with the sub-tropical ridge.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 01/0730 UTC by Perth TCWC.

霧峰追風者

JTWC 00Z速報升格"TS"，編號01S，逐漸增強。

Meow

BMKG忙翻了，好不容易6小時前降Cempaka到TD，現在又命名Dahlia。

SITUATION
At 12:00 UTC Tropical Cyclone DAHLIA 998 hPa was within 30 nautical miles of 8,5 S 100,8 E moving west at 2 knots.

FORECAST
Clockwise winds reaching 35 knots expected to decrease to 45 knots in the next 24 hours.
High seas may exceed Rough to Very Rough scale and rising swell.

00:00 UTC 30 November:  Within 60 nautical miles of 8,8 S 100,6 E
                        Central pressure 996 hPa.
                        Wind speed reaching 40 knots near centre.
12:00 UTC 30 November: Within 90 nautical miles of 9,4 S 102,2 E
                        Central pressure 995 hPa.
                        Wind speed reaching 45 knots near centre.

霧峰追風者

JTWC 04Z發佈TCFA，逐漸增強。

WTXS22 PGTW 290430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
155 NM EITHER SIDE OF A LINE FROM 8.5S 100.7E TO 10.3S 107.5E
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 25 TO 30 KNOTS. METSAT IMAGERY AT
290400Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 8.5S
101.0E. THE SYSTEM IS MOVING EASTWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96S) PREVIOUSLY LOCATED
NEAR 8.4S 101.2E IS NOW LOCATED NEAR 8.5S 101.0E, APPROXIMATELY
300NM WEST-NORTHWEST OF CHRISTMAS ISLAND, AUSTRALIA. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A BROAD LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH FORMATIVE CONVECTIVE BANDING OVER THE
WESTERN SEMI-CIRCLE. A 282328Z WINDSAT 37GHZ IMAGE SHOWS A
CONSOLIDATING LLCC WITH IMPROVED BANDING WRAPPING INTO A DEFINED
CENTER. A 290312Z ASCAT IMAGE SHOWS NUMEROUS 30-KNOT WINDS
ASSOCIATED WITH THE PRIMARY CONVECTIVE BAND. UPPER-LEVEL ANALYSIS
INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH MODERATE TO STRONG
(25 TO 35 KNOTS) VERTICAL WIND SHEAR OFFSET BY GOOD POLEWARD
OUTFLOW. GLOBAL DYNAMIC MODELS INDICATE THAT 96S WILL STEADILY
DEVELOP WHILE TRACKING EAST-SOUTHEASTWARD TO SOUTHEASTWARD INTO A
MORE FAVORABLE UPPER-LEVEL ENVIRONMENT OVER THE NEXT 2 DAYS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 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
300430Z.//
NNNN

t02436

BoM開始發報，展望中已編號03U。

A second tropical low (03U lies north of the region near 7.6S 98.6E. It is expected to move generally southeast during the next few days, and it may develop as it does so, possibly reaching tropical cyclone intensity from Thursday. Its likely to enter the Western Region, to the south of Java on Friday.
From Thursday the system may move close to Christmas Island leading to a period of gusty winds, increased shower and thunderstorm activity and rough seas.

Likelihood of this system being a tropical cyclone in the Western Region on:
Wednesday:Very Low
Thursday: Low
Friday:High