老農民版夜神月

  基本資料  
編號　　　　：15 L
擾動編號日期：2019 年 10 月 13 日 19 時
撤編日期　　：2019 年 10 月 17 日 21 時
94L INVEST 191013 1200 11.9N 15.6W ATL 20 1008


  NHC：30%  

2. A tropical wave, accompanied by a broad area of low pressure, is
producing a concentrated area of showers and thunderstorms over
portions of western Africa.  The wave is expected to move
west-northwestward over the next day or so and emerge off the
coast of Africa later this afternoon.  Environmental conditions are
expected to be conducive for some additional development to occur
during the next few days while the system moves west-northwestward
to northwestward toward the Cabo Verde Islands on Tuesday and
Wednesday.  Strong upper-level winds should prevent additional
development by midweek.  Interests in and around the Cabo Verde
Islands should monitor the progress of this disturbance.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...50 percent.

MAX:30,1006

老農民版夜神月

NHC提升評級為Medium,50%/70%

1. A vigorous tropical wave, accompanied by a well-defined low pressure
system, has emerged over the far eastern tropical Atlantic Ocean
just west of the coast of Guinea-Bissau.  Showers and thunderstorms
are beginning to show signs of organization, and environmental
conditions are expected to be conducive for the development of a
tropical depression during the next few days while the disturbance
moves west-northwestward to northwestward over or just east of the
Cabo Verde Islands.  Strong upper-level winds should prevent any
significant development by midweek.  Interests in and around the
Cabo Verde Islands should monitor the progress of this system.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...70 percent.

老農民版夜神月

NHC展望已提升至High,80%/80%

1. A large low pressure system located over the far eastern tropical
Atlantic Ocean about 300 miles southeast of the Cabo Verde Islands
is moving slowly west-northwestward. Showers and thunderstorms are
showing some signs of organization, and environmental conditions are
expected to be conducive for a tropical depression to form during
the next day or so while the disturbance moves west-northwestward to
northwestward near the Cabo Verde Islands. Strong upper-level winds
should prevent any further development by midweek.  This system is
forecast to bring locally heavy rainfall and gusty winds to portions
of the Cabo Verde Islands later today through Tuesday, and interests
there should monitor the progress of this system.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...80 percent.

FWC-N於14/12Z發布TCFA

SUBJ/TROPICAL CYCLONE FORMATION ALERT//
WTNT21 KNGU 141200
RMKS/1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE
WITHIN 100 NM EITHER SIDE OF A LINE FROM 13.3N 18.2W TO 14.5N 20.8W
WITHIN THE NEXT 00 TO 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 140600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 13.5N 18.5W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 07
KNOTS.
2. REMARKS: THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH. AN AREA OF LOW
PRESSURE HAS FORMED OVER THE WESTERN COAST OF AFRICA. EVIRONMENTAL
CONDITIONS WILL BE CONDUCIVE FOR FURTHER DEVELOPMENT. A SLIGHT
INCREASE IN CONVECTIVE ORGANIZATION COULD RESULT IN THE FORMATION OF
A TROPICAL DEPRESSION OVER THE NEXT 24 HOURS. THE SYSTEM IS
FORECAST TO MOVE WEST-NORTHWESTWARD 05-10 KTS OVER THE NEXT
SEVERAL HOURS.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 151200Z.//

t02436

21Z已升格15L，巔峰上望40節，5天後消散。

000
WTNT45 KNHC 142040
TCDAT5

Tropical Depression Fifteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL152019
500 PM AST Mon Oct 14 2019

The large low pressure system that moved off the coast of Africa
yesterday has gradually become better defined based on earlier ASCAT
scatterometer wind data and recent visible satellite imagery.
Several fragmented curved bands have been developing during the past
several hours, especially in the northern semicircle, and the
aforementioned ASCAT passes indicated that winds of 30-32 kt were
present northwest of the center. The initial intensity is set at 30
kt based on a blend of the scatterometer wind data and a satellite
intensity estimate of T1.5/25 kt from SAB, and the rather broad
nature of the depression.

A surge of mid-level dry air has recently penetrated into the
inner-core region, causing some erosion of the central deep
convection. However, this is expected to be a temporary condition
with convection returning later tonight and early Tuesday during the
normal nocturnal convective maximum period. However, the large size
of the cyclone -- more than 1000 nmi wide -- should prevent any
rapid or significant intensification. With very low vertical shear
conditions forecast by the GFS and ECMWF models to continue for the
next 24 to 36 hours, at least some modest strengthening seems likely
given the unusually warm SSTs of near 28.5 deg C that the cyclone
will be traversing during that time. By 48 hours, the shear is
forecast to increase from the southwest in excess of 25 kt,
resulting in weakening into a remnant low shortly thereafter. By 72
hours and beyond, the shear is expected to increase to more than 40
kt, which will cause rapid weakening and dissipation by the 120-h
period, if not sooner. The official intensity forecast is similar to
a blend of the NOAA-HCCA and IVCN consensus models, and the GFS-
and ECMWF-based Decay-SHIPS statistical intensity models.

The initial motion estimate is northwestward or 310/07 kt. The
latest NHC model guidance is in very good agreement on the tropical
cyclone moving generally northwestward around the southwestern
periphery of a deep-layer ridge for the next 48 hours. Thereafter,
the models diverge significantly based on how soon the cyclone
weakens and turns westward within the low-level easterly trade wind
flow. The ECMWF holds on to a vertically deeper system a little
longer than the GFS, UKMET, HWRF, and HMON models, resulting in a
longer northwestward track. However, since the cyclone will likely
have become a vertically shallow remnant low by 72 hours, the NHC
official forecast track is a little to the left of ECMWF solution,
closer to the TVCN and HCCA consensus model tracks at 72 and 96 h.

FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 13.2N  20.2W   30 KT  35 MPH
12H  15/0600Z 14.3N  21.1W   35 KT  40 MPH
24H  15/1800Z 15.5N  22.4W   40 KT  45 MPH
36H  16/0600Z 16.7N  23.4W   40 KT  45 MPH
48H  16/1800Z 18.1N  24.6W   35 KT  40 MPH
72H  17/1800Z 20.4N  26.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  18/1800Z 21.4N  29.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  19/1800Z...DISSIPATED

$$
Forecaster Stewart