0908morakot

  三級颶風  
編號：14 L
名稱：Lee

  基本資料  
擾動編號日期：2017 年 09 月 14 日 20 時
命名日期　　：2017 年 09 月 16 日 23 時
撤編日期　　：2017 年 09 月 22 日 18 時
98L編號日期：2017 年 09 月 22 日 23 時
二次升格日期：2017 年 09 月 23 日 11 時
撤編日期　　：2017 年 09 月 00 日 00 時
登陸地點　　：暫無

  巔峰時期資料  
近中心最強風速 ：100  kt
海平面最低氣壓 ：965 毫巴

  過去路徑圖  

  擾動編號資料  
97L.INVEST.20kts.1012mb.9.5N.20.5W


NHC:30%

2. Another tropical wave, located between the west coast of Africa and
the Cabo Verde Islands, is producing a large area of disorganized
shower and thunderstorm activity. Some development of this system is
possible over the next few days before upper-level winds become less
favorable.  The system is forecast to move westward at 10 to 15 mph
across the far eastern tropical Atlantic for the next several days.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...40 percent.

以上資料來自：NHC、颱風論壇整理製作

霧峰追風者

NHC 展望提高至60%，型態良好。

2. Another tropical wave, located south of the Cabo Verde Islands, is
producing a large area of shower and thunderstorm activity.  This
system has become much better organized since yesterday and could
become a tropical depression during the next couple of days before
upper-level winds become less conducive for development.  The
disturbance is forecast to move westward to west-northwestward at 10
to 15 mph across the far eastern tropical Atlantic for the next
several days.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...70 percent.

霧峰追風者

NHC 展望提高至80%。

located about 300 miles south of the Cabo Verde Islands have
continued to become better organized this afternoon. Environmental
conditions are expected to remain conducive for development, and
a tropical depression is likely to form tonight or Friday.  This
system is forecast to move westward to west-northwestward at 10
to 15 mph across the eastern tropical Atlantic during the next
couple of days.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

霧峰追風者

快速發展，00Z升格"14L"。

t02436

第一報，暫時上望60節。

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Fourteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL142017
1100 PM AST Thu Sep 14 2017

Convection associated with an area of low pressure over the far
eastern Atlantic has become much better organized during the past 12
hours, with an increase in banding over the western portion of the
circulation.  A Dvorak classification of 2.0 from TAFB suggests that
the intensity is around 30 kt.  The system is currently embedded
within an area of light to moderate easterly shear.  This should not
prevent the system from gradually strengthening while it moves over
warm water during the next couple of days.  After that time, a mid-
to upper-level trough over the central Atlantic is expected to cause
an increase in southwesterly shear, which could become quite strong
by days 4 and 5.  As a result, weakening is expected late in the
forest period.  The NHC intensity forecast is between the higher
statistical guidance and the lower dynamical models.

The depression is moving west-northwestward or 285/19 kt. A high
pressure ridge currently over the eastern Atlantic is forecast to
weaken as the aforementioned trough develops over the central
Atlantic by early next week.  This should cause a significant
reduction in the forward speed of the depression over the weekend.
There is some spread in the track guidance later in the period, with
the GFS taking a stronger cyclone more northward, while the EC takes
a weaker system more westward.  The NHC track is between these
solutions and is close to the TVCX and HCCA consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 10.7N  25.4W   30 KT  35 MPH
12H  15/1200Z 11.2N  27.4W   40 KT  45 MPH
24H  16/0000Z 11.5N  29.3W   45 KT  50 MPH
36H  16/1200Z 11.5N  30.7W   50 KT  60 MPH
48H  17/0000Z 11.5N  31.7W   55 KT  65 MPH
72H  18/0000Z 11.8N  34.5W   60 KT  70 MPH
96H  19/0000Z 12.8N  38.6W   50 KT  60 MPH
120H  20/0000Z 14.4N  43.3W   40 KT  45 MPH

$$
Forecaster Brown

NNNN

霧峰追風者

NHC 12Z命名"LEE"，逐漸西移。

000
WTNT44 KNHC 161459 CCA
TCDAT4

Tropical Storm Lee Discussion Number   7...Corrected
NWS National Hurricane Center Miami FL       AL142017
1100 AM AST Sat Sep 16 2017

Corrected to include missing word in intensity discussion

Deep convection has increased in intensity and coverage since this
time yesterday, and a recent partial ASCAT pass from around 1100
UTC indicated that the system is now producing tropical-storm-force
winds at least to the east of its center.  Based on these data, the
depression is upgraded to Tropical Storm Lee with maximum winds of
35 kt.  Lee has been able to strengthen a little despite about 15
kt of north-northwesterly shear.  The cyclone appears to be located
in a sweet spot of relatively low shear, with much stronger upper-
level westerly winds located not too far to the north, and it may be
able to thread the needle of lower shear for another 36 hours or so.
After that time, the westerlies drop southward, and Lee will likely
be hammered by 30 kt of westerly shear by 48 hours.  With all that
in mind, Lee is forecast to strengthen only slightly over the next
day or so, with weakening expected to begin by day 3.  The NHC
intensity forecast is close to the intensity consensus and HCCA, and
Lee may ultimately degenerate into a remnant low by day 5.

Lee's initial motion is estimated to be 265/10 kt.  The storm is
located to the south of a weak mid-level ridge, and it is expected
to move generally westward or west-northwestward for the entire
forecast period.  Although some of the track models are showing a
more pronounced poleward motion, Lee's relatively low intensity and
eventual weakening will likely keep it steered by lower-level flow.
As a result, the NHC track forecast is near the southern edge of
the guidance envelope, although not quite as far south as the ECMWF
model.  This forecast is not too different from the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 12.5N  33.1W   35 KT  40 MPH
12H  17/0000Z 12.4N  34.1W   40 KT  45 MPH
24H  17/1200Z 12.5N  35.3W   40 KT  45 MPH
36H  18/0000Z 12.9N  36.7W   40 KT  45 MPH
48H  18/1200Z 13.6N  38.4W   40 KT  45 MPH
72H  19/1200Z 15.6N  42.3W   35 KT  40 MPH
96H  20/1200Z 17.0N  46.0W   30 KT  35 MPH
120H  21/1200Z 18.0N  49.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg

t02436

我們的李先生已經乾掉了....@@
15Z根據風場降TD，不再看好回到TS級別。

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Lee Discussion Number  11
NWS National Hurricane Center Miami FL       AL142017
1100 AM AST Sun Sep 17 2017

An 1144 UTC ASCAT pass indicated that Lee is no longer producing
tropical-storm-force winds.  In addition, deep convection is
fizzling, and there are only a few convective elements remaining in
a band to the south of the center.  Lee is downgraded to a tropical
depression with 30-kt winds, and even that could be generous given
what the ASCAT data is showing.  Since the cyclone is already
struggling in its current environment, it probably won't do much
better going forward since vertical shear is expected to increase
to 30 kt in about 24 hours. Therefore, gradual weakening is
expected, and Lee could degenerate into a remnant low by 48 hours,
if not sooner.  The GFS and ECMWF both dissipate the low in 3 to 4
days, so the new NHC forecast now shows that occurring by day 4.

Lee is moving westward, or 280/7 kt.  Even though the ridge to the
north of the cyclone is not very strong, Lee's weak nature should
cause it to be steered generally westward or west-northwestward for
the next 3 days before it dissipates.  The NHC track forecast
remains just south of the various consensus aids, and it is not too
different from the previous forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 13.0N  36.7W   30 KT  35 MPH
12H  18/0000Z 13.2N  37.8W   30 KT  35 MPH
24H  18/1200Z 13.8N  39.5W   30 KT  35 MPH
36H  19/0000Z 14.7N  41.2W   25 KT  30 MPH
48H  19/1200Z 15.7N  42.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
72H  20/1200Z 17.5N  45.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  21/1200Z...DISSIPATED

$$
Forecaster Berg

NNNN

霧峰追風者

NHC 展望提高至60%，目前中心爆對流，風速來到40kt，看看下報NHC會不回再次發報。

1. Showers and thunderstorms have increased near a low pressure area,
the remnants of Lee, located about 1000 miles east of the Leeward
Islands. Satellite wind data show that the low is already producing
gale-force winds, and only a small increase in the organization of
the deep convection would result in the regeneration of Lee.
However, the environmental conditions are only marginal favorable
for tropical cyclone formation.  This low is expected to move
northward over the central Atlantic Ocean.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.