霧峰追風者

基本資料  
編號              ：13 L
擾動編號日期： 2020 年 08 月 18 日 02 時
撤編日期       ： 2020 年 08 月 28 日 21 時
98L.INVEST.15kts-1006mb-12N-35W

2. A tropical wave over the eastern tropical Atlantic is forecast to
interact with another disturbance located several hundred miles
southwest of the Cabo Verde Islands within the next day or two. This
interaction is expected to lead to the formation of a broad area of
low pressure, and conditions are forecast to be conducive for the
development of a tropical depression during the middle-to-latter
part of this week while the system moves westward to west-
northwestward at 15 to 20 mph across the central and western
portions of the tropical Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...70 percent.

霧峰追風者

展望提升至60%。

2. Satellite images indicate that a broad area of low pressure located
about 700 miles west-southwest of the Cabo Verde Islands has become
better organized since yesterday, with increasing banding features
near the center.  Environmental conditions are conducive for further
development, and a tropical depression is likely to form within a
couple days while the system moves westward to west-northwestward
at 15 to 20 mph across the central and western portions of the
tropical Atlantic.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...90 percent.

霧峰追風者

NHC展望提升至70%。

2. A broad area of low pressure located a little over 700 miles
west-southwest of the Cabo Verde Islands is producing a
concentrated area of showers and thunderstorms displaced to the
west of an elongated surface circulation.  Environmental conditions
are conducive for further development, and a tropical depression is
likely to form within the next day or two while the system moves
westward to west-northwestward at 15 to 20 mph across the central
and western portions of the tropical Atlantic.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

老農民版夜神月

FWC-N18/1600Z發布TCFA

WTNT21 KNGU 181600
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE
WITHIN 100 NM EITHER SIDE OF A LINE FROM 11.5N 37.8W TO 11.4N 45.8W
WITHIN THE NEXT 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 35 KNOTS. METSAT
IMAGERY AT 181200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.5N 37.7W. THE SYSTEM IS MOVING WEST AT 17 KNOTS.
2. A BROAD AREA OF LOW PRESSURE LOCATED ABOUT 900 MILES WEST-
SOUTHWEST OF THE CABO VERDE ISLANDS IS PRODUCING A CONCENTRATED
AREA OF SHOWERS AND THUNDERSTORMS. ENVIRONMENTAL CONDITIONS ARE
CONDUCIVE FOR FURTHER DEVELOPMENT, AND A TROPICAL DEPRESSION IS
LIKELY TO FORM WITHIN THE NEXT DAY OR SO WHILE THE SYSTEM
MOVES WEST TO WEST-NORTHWEST AT 17 KNOTS ACROSS THE CENTRAL
AND WESTERN PORTIONS OF THE TROPICAL ATLANTIC.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
191600Z.//
BT
#0001
NNNN

霧峰追風者

NHC 展望提升至90%。

2. A broad and elongated area of low pressure located about 1000 miles
west-southwest of the Cabo Verde Islands continues to produce a
concentrated area of showers and thunderstorms on the west side of
the disturbance.  Environmental conditions are conducive for further
development, and a tropical depression is expected to form during
the next day or two while the system moves generally west-
northwestward at 15 to 20 mph across the central and western
portions of the tropical Atlantic.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...90 percent.

天篷大元帥

國家颶風中心：熱帶性低氣壓
同時發出熱帶風暴觀察預警
原文：

465
WTNT43 KNHC 200252
TCDAT3

Tropical Depression Thirteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL132020
1100 PM AST Wed Aug 19 2020

The low pressure system that NHC has been monitoring over the
central tropical Atlantic has now developed a well-defined center of
circulation and maintained enough organized deep convection to be
classified as a tropical depression, the thirteenth cyclone of the
2020 Atlantic hurricane season.  The depression already has some
banding features on its north and west sides as evident in
geostationary satellite and microwave images. The initial intensity
is set at 30 kt based on ASCAT data from around 0100 UTC and a
T2.0/30 kt Dvorak classifications from TAFB.

The depression has been moving fairly quickly to the west-northwest,
with the latest initial motion estimated to be 295/17 kt.  It should
be noted that the initial motion is somewhat uncertain given that
the system has only recently formed.  A subtropical ridge currently
over the central Atlantic is expected to build westward during the
next several days and should be the primary steering feature for
the depression through the forecast period.  This pattern should
keep the depression on a fairly quick west-northwest track during
the next several days, taking the cyclone near the northern
Leeward Islands by Friday night and near the Greater Antilles
and southeastern Bahamas this weekend.  The models are in fairly
good agreement, but there is some north-south spread with the GFS
being on the southern side of the guidance envelope and the ECMWF
on the northern end.  The NHC track forecast lies down the middle
of the guidance suite.

The environmental conditions appear generally favorable for the
depression to strengthen, with the wind shear expected to remain
relatively low while the system moves over warm SSTs and remains in
a moist airmass.  These conditions should promote gradual
strengthening and it seems quite likely that the cyclone will be a
tropical storm when it moves near or north of the northern Leeward
Islands in a couple of days.  The bigger question is how
much interaction will there be with the Greater Antilles.  If the
depression moves on the south side of the guidance envelope,
further strengthening would be limited due to land interaction.  
Conversely, if the system gains more latitude and moves north of
these highly topographic islands, it could have the opportunity for
more significant intensification. The NHC intensity forecast, which
is of low confidence, is roughly near the middle of the guidance
envelope.

Key Messages:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands by Friday night, and Tropical Storm Watches
have been issued for some of these islands.  Heavy rainfall is
likely across this area beginning late Friday.

2.  There is a risk of tropical storm conditions in the Virgin
Islands and Puerto Rico Friday night and Saturday and Tropical
Storm Watches could be required for these islands tomorrow.  
Interests there should closely monitor the progress of this system.

3. The details of the long-range track and intensity forecasts are
more uncertain than usual since the system could move over portions
of the Greater Antilles this weekend.  However, this system could
bring some rainfall and wind impacts to portions of Hispaniola,
Cuba, the Bahamas, and Florida this weekend and early next week.
Interests there should monitor this system's progress and updates to
the forecast over the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0300Z 14.6N  47.9W   30 KT  35 MPH
12H  20/1200Z 16.1N  50.8W   30 KT  35 MPH
24H  21/0000Z 17.4N  54.6W   35 KT  40 MPH
36H  21/1200Z 18.4N  58.4W   40 KT  45 MPH
48H  22/0000Z 19.1N  62.1W   45 KT  50 MPH
60H  22/1200Z 19.9N  65.9W   50 KT  60 MPH
72H  23/0000Z 20.8N  69.7W   55 KT  65 MPH
96H  24/0000Z 22.9N  76.7W   60 KT  70 MPH
120H  25/0000Z 26.2N  82.2W   60 KT  70 MPH

$$
Forecaster Cangialosi

機器翻譯(翻譯粗劣僅供參考)：

465
WTNT43 KNHC 200252
TCDAT3

熱帶低氣壓十三討論1
NWS邁阿密颶風中心AL132020
1100 PM AST星期三2020年8月19日

NHC一直在
熱帶中部大西洋地區進行監測的低壓系統現已建立了明確的
環流中心和維持了足夠的有組織的深對流，被
歸類為熱帶低壓，這是
2020年大西洋颶風季的第13次颶風。從
對
地靜止衛星和微波圖像中可以明顯看出，該凹陷在其北側和西側已經具有一定的分帶特徵。初始強度
根據大約0100 UTC的ASCAT數據和
TAFB的T2.0 / 30 kt Dvorak分類，將其設置為30 kt 。

蕭條一直相當迅速地向西北偏西移動，
最新的初始動向估計為295/17 kt。應該
注意的是，
由於系統是最近才形成的，初始運動有些不確定。目前
在大西洋中部的亞熱帶海脊預計將在
未來幾天內向西建造，並且應該是
整個預測期內低氣壓的主要轉向特徵。這種模式將
在
接下來的幾天中使低氣壓保持在相當快的西北偏西軌道上，從而使氣旋靠近北部
背風群島到週五晚上，
本週末靠近大安的列斯群島和巴哈馬東南部。這些模型非常
吻合，但是有一些南北分佈，GFS
在引導包絡線的南側，而ECMWF
在北端。NHC跟踪預報位於
指導套件的中間。

環境條件似乎通常有利於
凹陷的增強，
當系統在溫暖的海溫上方移動並保持在
潮濕的氣團中時，風切變預計將保持相對較低。這些條件應促進逐步
加強，而且旋風將很有可能成為
幾天后
移動到背風群島北部或北部以北的熱帶風暴。更大的問題是
與大安的列斯群島之間將會有多少互動。如果
凹陷在引導層的南側移動，
由於土地相互作用，進一步的加強將受到限制。  
相反，如果系統獲得更多的緯度並向
這些高地形島嶼北側移動，則可能有機會進行
更大程度的集約化。NHC強度預測
的可信度較低，大約在指導
範圍的中間。

關鍵信息：

1.熱帶風暴的條件可能在部分地區發生
週五晚在背風群島北部
，其中一些島嶼已發布熱帶風暴監視表。
從周五晚開始，整個地區可能會出現強降雨。

2.
週五晚上和周六在維爾京群島和波多黎各存在熱帶風暴條件的風險，
明天可能需要對這些島嶼進行熱帶風暴監視。  
那裡的利益應密切監視該系統的進度。

3.遠程航跡和強度預報的細節
比平時更加不確定，因為該系統
本週末可能在大安的列斯群島上空移動。但是，該系統可能
會給部分西班牙裔帶來降雨和風影響，
古巴，巴哈馬和佛羅里達本週末和下周初。
那裡的興趣者應監視此系統的進度，並
在未來幾天內更新預測。

預測位置和最大

風速初始化20 / 0300Z 14.6N 47.9W 30 KT 35 MPH
12H 20 / 1200Z 16.1N 50.8W 30 KT 35 MPH
24H 21 / 0000Z 17.4N 54.6W 35 KT 40 MPH
36H 21 / 1200Z 18.4N 58.4W 40 KT 45 MPH
48H 22 / 0000Z 19.1N 62.1W 45 KT 50 MPH
60H 22 / 1200Z 19.9N 65.9W 50 KT 60 MPH
72H 23 / 0000Z 20.8N 69.7W 55 KT 65 MPH
96H 24 / 0000Z 22.9N 76.7W 60 KT 70 MPH
120H 25 / 0000Z 26.2N 82.2W 60 KT 70 MPH

$$
預報員Cangialosi

霧峰追風者

NHC 強度上望65KT不封頂，將直撲佛州。

000
WTNT43 KNHC 201452
TCDAT3

Tropical Depression Thirteen Discussion Number   3
NWS National Hurricane Center Miami FL       AL132020
1100 AM AST Thu Aug 20 2020

The organization of the depression has not changed much overnight
or this morning.  An area of convection has persisted near the
estimated center, with some banding noted over the northwestern
portion of the circulation.  An earlier SSMIS overpass was very
helpful in locating the center of what appears to be a small
circulation.  A very recent ASCAT overpass has also revealed a
small circulation that is weak on the southeastern side, but with
winds near tropical storm strength to the north of the center.  The
ASCAT data along with subjective Dvorak classification from TAFB and
SAB support maintaining the 30-kt initial intensity.

The depression continues to move briskly west-northwestward or
290/18 kt.  The track forecast philosophy has not changed from
before.  A subtropical ridge over the central Atlantic is forecast
to build westward and strengthen over the next several days.  This
pattern is expected to keep the cyclone on a west-northwestward
heading throughout the forecast period.  The dynamical models
continue to agree on this overall scenario, but there some
differences in both forward speed and how close it gets to the
Greater Antilles.  In general, the models that indicate a stronger
cyclone favor a more northern track, while those which depicted a
weaker system are along the southern and faster side of the
envelope.  The latest consensus aids are little north of the
previous track, and the new NHC forecast lies between the HFIP
corrected consensus and the TVCA multi-model consensus.  This is
slightly north of the previous advisory, and not far from the GFS
ensemble mean.

The environment consisting of light to moderate vertical wind shear
is expected to allow for gradual strengthening over the next few
days, and the NHC forecast calls for the system to become a tropical
storm later today or tonight.  The upper-level wind pattern is
expected to remain favorable in the latter portion of the forecast
period, and if there is minimal land interaction, a faster rate of
strengthening is possible at that time. The NHC intensity foreast
now shows the system becoming a hurricane by 96 hours, but it is a
little lower than the consensus aids at days 4 and 5 due to
uncertainty in how much the system will interact with the Greater
Antilles.

Key Messages:

1. Tropical storm conditions are possible across portions of the
northern Leeward Islands by Friday night, and Tropical Storm Watches
have been issued for some of these islands.  Heavy rainfall is
likely across this area beginning late Friday.

2.  There is a risk of tropical storm conditions in the Virgin
Islands and Puerto Rico Friday night and Saturday and Tropical
Storm Watches could be required for these islands later today.
Interests there should closely monitor the progress of this system.

3.  The details of the long-range track and intensity forecasts are
more uncertain than usual since the system could move over portions
of the Greater Antilles this weekend.  However, this system could
bring some storm surge, rainfall and wind impacts to portions of
Hispaniola, Cuba, the Bahamas, and Florida this weekend and early
next week. Interests there should monitor this system's progress
and updates to the forecast over the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 16.0N  52.0W   30 KT  35 MPH
12H  21/0000Z 17.0N  54.7W   35 KT  40 MPH
24H  21/1200Z 18.0N  58.3W   40 KT  45 MPH
36H  22/0000Z 18.9N  61.6W   45 KT  50 MPH
48H  22/1200Z 19.6N  64.7W   50 KT  60 MPH
60H  23/0000Z 20.4N  68.1W   55 KT  65 MPH
72H  23/1200Z 21.5N  71.8W   60 KT  70 MPH
96H  24/1200Z 24.0N  78.6W   65 KT  75 MPH
120H  25/1200Z 27.0N  83.4W   65 KT  75 MPH

$$
Forecaster Brown

老農民版夜神月

NHC特報升格TS,命名Laura

WTNT63 KNHC 211305
TCUAT3

Tropical Storm Laura Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL132020
905 AM AST Fri Aug 21 2020

...NOAA HURRICANE HUNTER AIRCRAFT FINDS THAT THE DEPRESSION HAS
STRENGTHENED TO TROPICAL STORM LAURA...

Data from a NOAA Hurricane Hunter aircraft indicate that Tropical
Depression Thirteen has strengthened and is now Tropical Storm
Laura with maximum sustained winds of around 45 mph (75 km/h). The
aircraft also found that the center of Laura is located south of the
previously estimated position. These changes will be reflected in
the track and intensity forecasts with the upcoming advisory that
will be issued at 1100 AM AST (1500 UTC).


SUMMARY OF 905 AM AST...1305 UTC...INFORMATION
---------------------------------------------------
LOCATION...17.0N 59.8W
ABOUT 230 MI...375 KM ESE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES

$$
Forecaster Brennan/Pasch