周子堯@FB

  四級颶風  
編號：09 L
名稱：Harvey

  基本資料  
擾動編號日期：2017 年 08 月 13 日 17 時
命名日期　　：2017 年 08 月 17 日 05 時
二次升格日期：2017 年 08 月 23 日 23 時
撤編日期　　：2017 年 08 月 00 日 00 時
登陸地點　　：墨西哥
                         美國 德克薩斯州
                                 路易斯安那州 卡梅倫郡

  巔峰時期資料  
近中心最強風速
國家颶風中心(NHC)：115 kts
海平面最低氣壓 ：938 百帕

  過去路徑圖  

  擾動編號資料  
91L.INVEST.25kts-1010mb-13.5N-18.1W


NHC : 0%

1. A tropical wave that has just emerged off the west coast of Africa
is forecast to move westward over the next couple of days and merge
with a broad area of low pressure located southwest of the Cabo
Verde Islands. Thereafter, environmental conditions are expected to
be conducive for gradual development of the system while it moves
westward to west-northwestward at 10 to 15 mph over the open
tropical Atlantic Ocean.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

以上資料來自：NHC、颱風論壇整理製作

霧峰追風者

NHC 展望10%。

1. A large and complex area of disturbed weather to the south and
southwest of the Cabo Verde Islands is associated with a broad
trough of low pressure and a tropical wave.  These systems are
forecast to merge over the next day or two, and environmental
conditions are then expected to be conducive for development of
this disturbance later this week while it moves westward at about
15 mph over the tropical Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...40 percent.

霧峰追風者

NHC 展望提升至50%

1. Showers and thunderstorms associated with a low pressure system
located about 650 miles east of the Lesser Antilles have become
a little more concentrated this afternoon.  Upper-level winds are
forecast to become more conducive for development during the next
day or so while the low moves westward at 15 to 20 mph across the
tropical Atlantic Ocean, crossing into the Caribbean Sea on Friday.
Regardless of development, locally heavy rainfall and gusty winds
are expected to spread across portions of the Lesser Antilles on
Thursday night and Friday, and interests there and elsewhere in
the eastern Caribbean should monitor the progress of this
disturbance. An Air Force Reserve reconnaissance aircraft is
scheduled to investigate this system on Thursday, if necessary.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...60 percent.

霧峰追風者

nhc 升格"潛在熱帶氣旋09L"，穩定西移。

000
WTNT44 KNHC 171440
TCDAT4

Potential Tropical Cyclone Nine Discussion Number   1
NWS National Hurricane Center Miami FL       AL092017
1100 AM AST Thu Aug 17 2017

Satellite imagery, including experimental 1-minute data from
GOES-16, indicates that the circulation of the low pressure area
east of the Lesser Antilles is becoming better defined, and that a
cluster of strong convection has formed just west of the center.
Based on this and the potential for the system to become a tropical
storm before reaching the Lesser Antilles, advisories are being
initiated as a potential tropical cyclone.  An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate the system
this afternoon, and it is likely the aircraft will find a tropical
cyclone has formed.

The initial motion is 270/15.  A deep-layer ridge to the north of
the system should steer it generally just north of due west through
the forecast period, with this motion expected to bring the system
through the Lesser Antilles and into the eastern Caribbean Sea in
24-36 h, into the central Caribbean by 72 h, and to the western
Caribbean by 96-120 h.  The forecast track lies near the center of
the tightly clustered guidance envelope and lies near the various
consensus models.

The system is in an area of moderate easterly vertical shear, and
the large-scale models suggest that light/moderate shear should
continue through the forecast period.  This seems favorable for
strengthening, and the SHIPS and LGEM models show slow, but steady,
intensification.  However, the GFS and ECMWF models forecast the
system to degenerate to an easterly wave over the central Caribbean
Sea, possibly due to dry air entrainment.  The intensity forecast
follows the trend of the SHIPS/LGEM models, but it respects the
GFS/ECMWF forecasts by being on the low side of the intensity
guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 13.1N  54.1W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
12H  18/0000Z 13.1N  56.4W   30 KT  35 MPH...TROPICAL DEPRESSION
24H  18/1200Z 13.2N  59.8W   35 KT  40 MPH
36H  19/0000Z 13.5N  63.2W   40 KT  45 MPH
48H  19/1200Z 13.9N  66.7W   45 KT  50 MPH
72H  20/1200Z 14.5N  74.5W   55 KT  65 MPH
96H  21/1200Z 15.5N  82.0W   65 KT  75 MPH
120H  22/1200Z 17.0N  87.5W   65 KT  75 MPH

$$
Forecaster Beven

霧峰追風者

NHC 命名"Harvey"，巔峰暫上望60Kts，穩定西移。

000
WTNT44 KNHC 172048
TCDAT4

Tropical Storm Harvey Discussion Number   2
NWS National Hurricane Center Miami FL       AL092017
500 PM AST Thu Aug 17 2017

An Air Force Reserve Hurricane Hunter aircraft found a well-defined
circulation in the low pressure area east of the Lesser Antilles,
with the center near a cluster of sheared, but strong, convection.
The aircraft data suggest that the maximum winds are near 35 kt
and that the central pressure is near 1004 mb.  Based on these
data, the disturbance is upgraded to Tropical Storm Harvey.

The initial motion is 270/16.  There is no change to the forecast
philosophy since the previous advisory.  A deep-layer ridge to the
north of the system should steer it quickly just north of due west
through the forecast period, with this motion expected to bring the
system through the Lesser Antilles and into the eastern Caribbean
Sea in 12-24 h, into the central Caribbean by 48-72 h, and to the
western Caribbean by 96-120 h.  One adjustment is that the 96-120 h
points have been nudged a little southward in response to a shift in
the guidance, and thus now lie closer to Central America than on
the previous forecast.  The forecast track again lies near the
center of the tightly clustered guidance envelope and the various
consensus models.

The system is in an area of moderate easterly vertical shear, and
the large-scale models suggest that light/moderate shear should
continue through at least 72 h.  The conflicting forecast scenarios
alluded to in the previous advisory remain, with the SHIPS and
LGEM models still showing steady intensification while the GFS and
ECMWF models still forecast degeneration to an easterly wave over
the central Caribbean.  The new intensity forecast again follows the
trend of the SHIPS/LGEM models, but it remains on the low side of
the guidance envelope out of respect for the GFS/ECMWF. The 96-120 h
intensities have been decreased a little due to the forecast track
showing more land interaction.


FORECAST POSITIONS AND MAX WINDS

INIT  17/2100Z 13.0N  55.8W   35 KT  40 MPH
12H  18/0600Z 13.1N  58.3W   35 KT  40 MPH
24H  18/1800Z 13.4N  61.6W   40 KT  45 MPH
36H  19/0600Z 13.7N  65.1W   45 KT  50 MPH
48H  19/1800Z 14.0N  68.8W   45 KT  50 MPH
72H  20/1800Z 14.5N  76.5W   55 KT  65 MPH
96H  21/1800Z 15.5N  83.5W   60 KT  70 MPH
120H  22/1800Z 17.0N  88.5W   55 KT  65 MPH...INLAND

$$
Forecaster Beven

周子堯@FB

NHC評級再次調到High~

1. A large area of disturbed weather over the northwestern Caribbean
Sea is associated with the remnants of Harvey. Satellite images
and surface observations indicate that the system lacks a
well-defined circulation and surface pressures are not falling at
this time. Although this system could still become better organized
while approaching the Yucatan peninsula tonight and early Tuesday,
tropical cyclone formation is not expected until the disturbance
moves into the Bay of Campeche on Wednesday where conditions are
favorable. Regardless of development, locally heavy rainfall and
gusty winds are likely to spread westward primarily across Belize
and the Yucatan Peninsula during the next couple of days.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

周子堯@FB

JTWC再發TCFA!

Meow

復活，預報TS上限登陸德克薩斯州。

000
WTNT44 KNHC 231450
TCDAT4

Tropical Depression Harvey Discussion Number  12
NWS National Hurricane Center Miami FL       AL092017
1000 AM CDT Wed Aug 23 2017

Air Force Reserve Hurricane Hunter data indicate that Harvey has
regenerated in the Bay of Campeche, with a closed circulation
noted and a central pressure of about 1006 mb.  The initial wind
speed is 30 kt based on SFMR data from the aircraft.

Harvey is not well organized at the moment, with an asymmetric cloud
pattern and a large radius of maximum wind.  The environment,
however, is conducive for intensification while Harvey moves over
the very warm Gulf of Mexico waters in light-to-moderate shear.  The
biggest hindrance to intensification in the short term is the poor
structure.  Thus the NHC forecast will only show a gradual increase
in wind speed during the first day, with a more significant
intensification after that time.  Although not explicitly forecast
below, we are anticipating Harvey being a hurricane at landfall
after the 48 hour forecast point.  This forecast agrees well with
the guidance, almost all of which shows a quickly intensifying
cyclone approaching the Texas coast.

Since the center has just recently formed, the initial motion is
difficult to estimate, but the long-term motion is 310/8.  Harvey is
expected to move more slowly toward the northwest or north-
northwest as it enters a weakness in the Atlantic subtropical ridge
during the next day or so.  The ridge slightly strengthens by late
Thursday, which should cause a faster northwestward motion by then.
Around the time of landfall, however, Harvey should enter an area of
weaker steering currents near the upper Texas coast as high pressure
rebuilds over the southwestern United States.  The storm should slow
down markedly over southeast Texas, and there is considerable
uncertainty on exactly how fast Harvey moves out of that state ahead
of the next mid-latitude trough.  For now the NHC forecast will just
drift Harvey generally toward the east at days 4 and 5, on
the slow side of the model consensus. Hopefully later G-IV flights
and special soundings over the southern United States will help
clarify the long range forecast.

Key Messages:

1. Harvey is likely to bring multiple hazards to portions of the
Texas coast beginning on Friday.

2. Several days of heavy rainfall are likely across portions of
eastern Texas, Louisiana, and the lower Mississippi Valley from
Friday through early next week. This rainfall could cause life-
threatening flooding. Please refer to products from your local
National Weather Service office (www.weather.gov) and the NOAA
Weather Prediction Center (www.wpc.ncep.noaa.gov) for more
information on the flooding hazard.

3. The National Weather Service has issued a Storm Surge Watch
from Port Mansfield to High Island, Texas. There is the possibility
of life-threatening inundation from rising water moving inland from
the coastline during the next 48 hours in these areas. For a
depiction of areas at risk, please see the National Weather Service
Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.

4. The Potential Storm Surge Flooding Map will also be available on
the NHC website by 1200 PM CDT. Remember that the Potential Storm
Surge Flooding Map does not represent a forecast of expected
inundation, but rather depicts a reasonable worst-case scenario -
the amount of inundation that has a 10 percent chance of being
exceeded at each individual location. Because the Flooding Map is
based on inputs that extend out only to about 72 hours, it best
represents the flooding potential in those locations within the
watch area.

5. Hurricane conditions are possible along the Texas coast from
Port Mansfield to San Luis Pass.


FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 21.5N  92.5W   30 KT  35 MPH
12H  24/0000Z 22.3N  93.2W   35 KT  40 MPH
24H  24/1200Z 23.8N  93.9W   40 KT  45 MPH
36H  25/0000Z 25.2N  94.9W   50 KT  60 MPH
48H  25/1200Z 26.7N  96.3W   60 KT  70 MPH
72H  26/1200Z 29.0N  97.3W   40 KT  45 MPH...INLAND
96H  27/1200Z 29.8N  96.9W   35 KT  40 MPH...INLAND
120H  28/1200Z 30.0N  95.0W   35 KT  40 MPH...INLAND

$$
Forecaster Blake