霧峰追風者

  熱帶低壓  
編號：11 L
名稱：無

  基本資料  
擾動編號日期：2018 年 09 月 20 日 07 時
升格日期　　：2018 年 09 月 22 日 11 時
撤編日期　　：2018 年 09 月 23 日 23 時
登陸地點　　：暫無

  巔峰時期資料  
近中心最強風速 ：30 kt
海平面最低氣壓 ：1007 百帕

  過去路徑圖  

  擾動編號資料  
97L.INVEST.25kts-1009mb-9.1N-46.0W

NHC : 10%

1. Shower activity associated with a tropical wave located about 1000
miles east of the Windward Islands has decreased some this morning.
Further development is becoming less likely since the environment is
becoming unfavorable for tropical cyclone formation.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...10 percent.

以上資料來自：NHC、颱風論壇整理製作

霧峰追風者

NHC 展望提升至40%

2. Updated: Shower and thunderstorm activity associated with a
well-defined low pressure system located about 500 miles east of the
Windward Islands has become better organized over the past few
hours, and a tropical depression could form later tonight or
Saturday. Strong upper-level winds and dry air are likely to
prevent additional development of this system by late this weekend
while it moves west-northwestward to northwestward at around 10 mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...40 percent.

霧峰追風者

NHC 升格熱帶低壓11L，首報暫時不看好命名。

562
WTNT41 KNHC 220249
TCDAT1

Tropical Depression Eleven Discussion Number   1
NWS National Hurricane Center Miami FL       AL112018
1100 PM AST Fri Sep 21 2018

The small, but well-defined, low pressure system located about 500
miles east of the Lesser Antilles has been producing steady
convection for the past several hours. Although this convection is
displaced to the south and east of the exposed low-level center due
to strong westerly wind shear, it has persisted long enough to meet
the NHC definition of a tropical cyclone. On this basis, advisories
are being initiated on Tropical Depression Eleven.

The initial intensity is set at 30 kt based on ASCAT data from
earlier today which showed a couple of 25-30 kt wind vectors in the
northeast quadrant of the circulation. The intensity guidance is in
extremely good agreement that the depression is unlikely to
strengthen. All of the global models forecast an increase in
upper-level winds over the small cyclone during the next 24 h. In
fact, SHIPS diagnostics indicate that the 850-200 mb shear could
exceed 30 kt by tomorrow morning, and will be near 40 kt within 48
h. As a result of this shear and some dry air also in the vicinity,
the dynamical models unanimously forecast dissipation within 72 h,
and most show that the depression will open into a trough of low
pressure sooner than that. The NHC forecast conservatively maintains
the tropical cyclone for 48 h, but it could weaken and dissipate
sooner than currently indicated.

The depression has recently been moving almost due west, but a
longer-term motion yields an initial motion of 290/5 kt. A break in
the subtropical ridge to the north of the depression should result
in fairly weak steering flow for the next day or two, and only a
slow west-northwestward to westward motion is anticipated. All of
the typically-reliable track models are in fairly good agreement on
this scenario.  The NHC forecast is very close to HCCA at all
forecast hours, and lies near the south edge of the tight guidance
envelope.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 13.1N  53.4W   30 KT  35 MPH
12H  22/1200Z 13.5N  54.2W   30 KT  35 MPH
24H  23/0000Z 13.8N  55.0W   30 KT  35 MPH
36H  23/1200Z 14.2N  56.3W   30 KT  35 MPH
48H  24/0000Z 14.5N  58.0W   25 KT  30 MPH
72H  25/0000Z...DISSIPATED

$$
Forecaster Zelinsky