周子堯@FB

基本資料  
編號　　　　：11 L
擾動編號日期：2020 年 08 月 09 日 20 時
撤編日期　　：2020 年 08 月 17 日 05 時
95L INVEST 200809 1200   ATL10.5N 26W 25 NA

king111807

NHC:20%

1. Showers and thunderstorms associated with a tropical wave located a
few hundred miles south-southwest of the Cabo Verde Islands are
showing some signs of organization.  Environmental conditions
could support some development of this system over the next
couple of days while it moves westward at 15 mph across the
tropical eastern Atlantic.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...20 percent.

king111807

NHC展望提升至Medium，40%

1. Showers and thunderstorms associated with a tropical wave located a
few hundred miles south-southwest of the Cabo Verde Islands continue
to show signs of organization.  However, recent satellite-derived
wind data indicates that the circulation remains elongated.  
Environmental conditions appear conducive enough to support
additional development of this system, and a tropical depression
could form during the next few days while it moves generally
westward at 15 mph across the tropical Atlantic.  Conditions are
likely to become less conducive for development late this week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.

king111807

NHC展望提升至60%

1. Showers and thunderstorms associated with a tropical wave and broad
area of low pressure located about 600 miles west-southwest of the
Cabo Verde Islands have changed little in organization since
yesterday.  Environmental conditions are expected to be somewhat
conducive for development to occur, and a tropical depression could
form during the next day or two while the disturbance moves
generally westward to west-northwestward at 10 to 15 mph across the
tropical Atlantic.  Conditions are forecast to become less
conducive for development by the end of the week.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

老農民版夜神月

NHC展望提升至High,70%

1. Thunderstorm activity associated with a large low pressure system
located more than 800 miles west-southwest of the Cabo Verde Islands
has increased and become a little better organized over the past
several hours. Environmental conditions are expected to be conducive
for development to occur, and a tropical depression is likely to
form during the next day or so while the disturbance moves westward
to west-northwestward at around 15 mph across the tropical Atlantic.
Conditions are forecast to become less conducive for development by
the end of the week.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

老農民版夜神月

支持發展至TS以上強度的模式相較於之前有略為增多,FWC-N發布TCFA

WTNT21 KNGU 111400
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE
WITHIN 100 NM EITHER SIDE OF A LINE FROM 11.2N 37.7W TO 12.8N 42.6W
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 111200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.0N 38.0W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 12
KNOTS.
2. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A PARTIALLY EXPOSED
SURFACE CIRCULATION, LOCATED ABOUT 900 MILES WEST-SOUTHWEST OF THE
CABO VERDE ISLANDS, HAVE BECOME BETTER ORGANIZED OVERNIGHT. UPPER
LEVEL-WINDS ARE EXPECTED TO BECOME MORE FAVORABLE WITHIN THE NEXT
12 HOURS OR SO AND A TROPICAL DEPRESSION IS LIKELY TO FORM LATER
TODAY OR TONIGHT AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 12 KT.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 121400Z.//

老農民版夜神月

NHC21Z升格TD11L,上望45KT

000
WTNT41 KNHC 112032
TCDAT1

Tropical Depression Eleven Discussion Number   1
NWS National Hurricane Center Miami FL       AL112020
500 PM AST Tue Aug 11 2020

Visible satellite imagery and ASCAT-C data from earlier in the day
have shown that the area of low pressure NHC has been monitoring
over the tropical Atlantic has developed a less-elongated
circulation with a well-defined center.  For the most part, deep
convection has persisted with the system since about this time
yesterday, save a brief period of warming cloud tops this morning.
The low now meets the criteria of a tropical cyclone, and
advisories have been initiated on Tropical Depression Eleven with
30-kt winds, in line with the latest Dvorak Current Intensity
numbers from TAFB and SAB.

The depression is moving westward, or 280/14 kt, to the south of a
large mid-tropospheric high centered over the central Atlantic.
This pattern is expected to evolve rather quickly, with a break
developing in the ridge over the central Atlantic by 48 hours.
This change should allow the depression to begin making more
poleward progress, moving west-northwestward from 36 hours until
the end of the forecast period.  The track models are in good
agreement on this scenario, as well as the system's forward speed,
and bring the center of the cyclone near or just to the north of
the northern Leeward Islands in 4-5 days.  This first NHC forecast
lies just to the north of the multi-model consensus cluster
through day 3, out of respect for the northern-lying ECMWF model,
and then is close to HCCA on days 4 and 5.

Conventional satellite imagery and Saharan Air Layer analyses
suggest that the center of the depression is being shielded from
much drier air to its north and west.  However, as has been the
case for a few days, at least 15 kt of easterly shear has been
pushing deep convection to the western side of the circulation.
This shear is expected to decrease over the next day or two, which
should allow for gradual strengthening to begin by 36 hours, and a
peak in the cyclone's intensity should occur in about 3 days.  For
this period, the NHC intensity forecast is a little above HCCA and
the IVCN intensity consensus.  After that time, westerly or
southwesterly shear is forecast to develop and increase to 20-30 kt
by days 4 and 5, which is likely to induce significant weakening.
In fact, it's notable that the conditions become hostile enough that
the global models are showing the system opening up into a trough
near the northern Leeward Islands by day 5, which is a plausible
alternate scenario.


FORECAST POSITIONS AND MAX WINDS

INIT  11/2100Z 11.7N  40.0W   30 KT  35 MPH
12H  12/0600Z 12.0N  42.1W   30 KT  35 MPH
24H  12/1800Z 12.4N  44.5W   30 KT  35 MPH
36H  13/0600Z 13.0N  46.9W   35 KT  40 MPH
48H  13/1800Z 13.9N  49.4W   40 KT  45 MPH
60H  14/0600Z 15.1N  51.8W   45 KT  50 MPH
72H  14/1800Z 16.4N  54.3W   45 KT  50 MPH
96H  15/1800Z 18.5N  59.5W   40 KT  45 MPH
120H  16/1800Z 21.0N  64.0W   35 KT  40 MPH

$$
Forecaster Berg

霧峰追風者

強度維持30KT，巔峰上望50KT。

000
WTNT41 KNHC 122042
TCDAT1

Tropical Depression Eleven Discussion Number   5
NWS National Hurricane Center Miami FL       AL112020
500 PM AST Wed Aug 12 2020

Satellite imagery this afternoon shows some changes in the
convection associated with Tropical Depression Eleven, as the
showers and thunderstorms are now occuring more in curved bands and
less in sheared bursts.  This is likely due to the southeasterly
shear which has been affecting the depression finally letting up.  
However, this change has not caused the satellite intensity
estimates to change significantly since the last advisory, so the
initial intensity is again 30 kt.

The initial motion remains a little north of due west, or
280/13 kt. There is almost no change to the forecast philosophy and
little change to the forecast track since the last advisory.  A
westward motion is expected to continue for another 6-12 h due to
easterly flow on the south side of a strong subtropical ridge
situated to the north of the cyclone.  After that, the global
models forecast a slight weakness to develop within the ridge,
allowing the cyclone to turn west-northwestward and continue that
motion through 96 h.  Between 96-120 h, the western end of the
ridge is forecast to weaken more, which should cause a turn toward
the northwest.  The new NHC forecast track remains just to the left
of the various consensus models.

The cyclone should be in an environment of light to moderate shear
through the next 48 h or so.  The intensity forecast again calls
for a peak intensity of 50 kt during this time, which is at the
high end of the intensity guidance.  After 60 h, the cyclone is
expected to encounter moderate to strong southwesterly shear
associated with a large upper-level trough over the southwestern
Atlantic.  This should cause at least steady weakening, and several
of the global models continue to forecast the cyclone to degenerate
to a tropical wave before 120 h.  The new intensity forecast again
expects the system to last longer than the global models, but still
shows weakening due to the shear after 72 h.  The new forecast has
only minor changes from the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 12.7N  45.7W   30 KT  35 MPH
12H  13/0600Z 13.0N  47.5W   35 KT  40 MPH
24H  13/1800Z 14.0N  49.9W   40 KT  45 MPH
36H  14/0600Z 15.2N  52.2W   45 KT  50 MPH
48H  14/1800Z 16.6N  54.8W   50 KT  60 MPH
60H  15/0600Z 17.8N  57.3W   50 KT  60 MPH
72H  15/1800Z 19.1N  59.7W   50 KT  60 MPH
96H  16/1800Z 21.5N  64.5W   40 KT  45 MPH
120H  17/1800Z 24.5N  67.0W   30 KT  35 MPH

$$
Forecaster Beven