shadow16

  一級颶風  
    編號：18 E
    名稱：Rachel


  基本資料  
    擾動編號日期：2014 年 09 月 21 日 21  時
　命名日期　　：2014 年 09 月 25 日 11  時
　消散日期　　：2014 年 10 月 03 日 01  時
　登陸地點　　：無

巔峰時期資料  
　近中心最強風速 / 海平面最低氣壓
    國家颶風中心 (NHC) ：    75     kts  ( CAT.1 )   
    海平面最低氣壓          ：   982   百帕
  過去路徑圖  


討論帖圖片  
99E.INVEST-20kts-1007mb-11.0N-93.5W


以上資料來自 : NHC、颱風論壇整理製作

shadow16

升格18E  但只上看TS




WTPZ43 KNHC 241450
TCDEP3

TROPICAL DEPRESSION EIGHTEEN-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182014
800 AM PDT WED SEP 24 2014

Convection associated with the area of low pressure located south of
Mexico has increased and persisted overnight.  The convection is not
extremely well organized due to strong northeasterly shear, however
Dvorak T-numbers of 2.0 from both SAB and TAFB suggest that the
system has enough organization to be classified as a tropical
depression.  The shear is causing the convection to be displaced to
the south and southwest of the low-level center.  The initial
intensity is set at 30 kt, which is in agreement with the latest
Dvorak classifications and earlier ASCAT data.  Strong upper-level
winds over the cyclone are expected to continue during the next 24
hours or so.  After that time, the depression is forecast to move
into an area of decreasing shear and some gradually strengthening is
predicted.  Late in the period, the cyclone will move into a less
favorable thermodynamic environment and weakening should commence.
The NHC intensity forecast is close to the SHIPS guidance.

The initial motion estimate is 285/12 kt.  The depression should
move west-northwestward to the south of a mid-level ridge over
Mexico during the next several days.  After 72 hours, the cyclone
will approach a weakness in the ridge caused by a mid-latitude
trough that will be moving into California.  This should cause the
cyclone to slow down and turn northwestward by days 4 and 5. The
track guidance is in good agreement with this scenario and the NHC
track is a blend of the latest ECMWF and GFS model solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 15.0N 105.5W   30 KT  35 MPH
12H  25/0000Z 15.7N 107.0W   30 KT  35 MPH
24H  25/1200Z 16.7N 109.0W   30 KT  35 MPH
36H  26/0000Z 17.7N 110.9W   35 KT  40 MPH
48H  26/1200Z 18.6N 112.7W   40 KT  45 MPH
72H  27/1200Z 20.0N 115.0W   45 KT  50 MPH
96H  28/1200Z 21.0N 116.0W   45 KT  50 MPH
120H  29/1200Z 22.0N 116.5W   40 KT  45 MPH

$$
Forecaster Brown

krichard2011

NHC 稍早命名 Rachel
不過強度方面仍不是很看好...
ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM

TROPICAL STORM RACHEL DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182014
800 PM PDT WED SEP 24 2014

Vigorous deep convection has expanded in association with the
tropical cyclone this evening, primarily in the southwestern
semicircle.  The asymmetric distribution of thunderstorms around the
system is due to about 25 kt of northeasterly vertical shear being
caused by a strong upper-level anticyclone to its north.  The
current intensity is based upon 35 kt estimates from both the
Satellite Analysis Branch and the Advanced Dvorak Technique, though
the Tropical Analysis and Forecast Branch suggests a slightly
stronger system.  Thus the cyclone is now named Tropical Storm
Rachel. The system may gradually intensify during the next two to
three days as the shear diminishes some.  However, Rachel should
also encounter cooler sea surface temperatures and drier low-level
air as it moves toward the west-northwest.  The system is expected
to peak in intensity as a moderate tropical storm around day 2 or 3,
followed by a gradual weakening.  The NHC official intensity
forecast is based upon the tightly clustered IVCN multi-model
ensemble and is about the same as the previous advisory.

The earlier ASCAT scatterometer pass suggested a radius of maximum
wind of around 40 nm, which helped to define the tropical-storm-
force wind radii now that the cyclone has strengthened.  The global
and regional hurricane models suggest that Rachel will remain rather
small in size.  A blend of these models with the climatology-
persistence technique is the basis for the NHC wind radii
predictions.

A 2333Z SSMIS microwave image assisted in locating the center of
Rachel, as the low-level swirl has remain tucked just under the
convective overcast. Rachel is moving toward the west at about
10 kt.  The tropical storm should turn toward the west-northwest
during the next two days as it moves around the periphery of the
mid-level subtropical ridge.  In about three days, a strong
short wave trough will be passing north of Rachel over California.
The new 18Z GFS and the hurricane models run from it respond by
turning Rachel northeastward toward Baja California, while the
older 12Z ECMWF and UK Met Office global models continue moving a
weaker Rachel west-northwestward.  The NHC official track splits the
difference and is slightly eastward from that of the previous
advisory, but not as far eastward as the TVCE multi-model ensemble.


FORECAST POSITIONS AND MAX WINDS

INIT  25/0300Z 15.3N 107.4W   35 KT  40 MPH
12H  25/1200Z 15.8N 108.8W   35 KT  40 MPH
24H  26/0000Z 16.9N 110.7W   40 KT  45 MPH
36H  26/1200Z 17.9N 112.5W   40 KT  45 MPH
48H  27/0000Z 18.6N 113.9W   45 KT  50 MPH
72H  28/0000Z 19.7N 115.5W   45 KT  50 MPH
96H  29/0000Z 20.5N 116.0W   40 KT  45 MPH
120H  30/0000Z 21.5N 116.0W   30 KT  35 MPH

krichard2011

相較於昨天深層對流
沒有完全覆蓋於中心附近的問題
最近幾張可見光雲圖
大致可以看出結構已有明顯改善
強度稍早NHC也提升至45KT 上看TS上限
路徑上處於低風切海溫也還算支持
不過北方的乾空氣也算是一個變數...






TROPICAL STORM RACHEL DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182014
800 AM PDT THU SEP 25 2014

The northeasterly shear that has been affecting the cyclone
during the past day or so appears to be decreasing, with the center
of Rachel now located beneath the cold cloud tops.  Dvorak intensity
estimates from both TAFB and SAB support an initial wind speed of 45
kt for this advisory.  The shear is expected to further decrease
over the next 24 to 36 hours and additional strengthening is likely
during this period.  The new NHC intensity forecast is above the
previous forecast and close to the SHIPS/LGEM guidance.  After 48
hours, Rachel will be moving over slightly cooler water and into a
drier airmass, which should cause steady weakening late in the
forecast period.

A recent SSMIS overpass was very helpful in locating the center
this morning.  The fixes indicate an initial motion of 295 degrees
at about 11 kt. Rachel should continue moving west-northwestward to
the south of a mid-level ridge over Mexico during the next 24 to 36
hours.  After that time, a trough approaching the west coast of the
United States will create a break in the ridge which should cause
Rachel to turn northwestward.  During the 3 to 5 day period, there
continues to be large differences in the model solutions.  The GFS,
GFDL, and HWRF take the cyclone northward, then northeastward, while
the ECMWF and UKMET show a weaker cyclone becoming nearly stationary
well southwest of the Baja peninsula.  The NHC track leans toward
the more northward solution, but it is not nearly as fast or as
far east as the GFS and GFDL models at days 4 and 5.

FORECAST POSITIONS AND MAX WINDS

INIT  25/1500Z 16.3N 109.6W   45 KT  50 MPH
12H  26/0000Z 17.1N 111.0W   50 KT  60 MPH
24H  26/1200Z 18.2N 112.9W   55 KT  65 MPH
36H  27/0000Z 19.0N 114.2W   55 KT  65 MPH
48H  27/1200Z 19.8N 115.0W   60 KT  70 MPH
72H  28/1200Z 21.5N 115.8W   55 KT  65 MPH
96H  29/1200Z 22.7N 115.5W   45 KT  50 MPH
120H  30/1200Z 23.5N 115.0W   30 KT  35 MPH

krichard2011

經過了一段時間的整合
結構終於像樣多了
連底層風眼都快要轉出來了
為OHC以經不是很高 加上西北側的乾空氣
要增強倒多強應該是多少受到限制了...
不過如果真的開眼說不定能挑戰一下 C1~C2左右的強度

CX723-A330

上到75kts了



小鋼炮一隻:

krichard2011

雖然發展的還算不錯
只是風眼沒有開得很成功
現在已近乎消散 也被NHC撤掉了
可惜沒什麼人關心她 就這樣默默退場了
覺得它有點可憐 ˇˇ
最後還是來發一下VIRRS的衛星影像吧...

不過老實說 從可見光來看的話
她這副模樣還挺美的 有另一種美感...