周子堯@FB

  基本資料  
編號　　　　：12 L
擾動編號日期：2018 年 09 月 21 日 09 時
撤編日期　　：2018 年 09 月 00 日 00 時
99L.INVEST.25kts-1007mb-9.3N-133.0W

t02436

NHC 15Z直接命名Kirk，巔峰上望50節。

310
WTNT42 KNHC 221436
TCDAT2

Tropical Storm Kirk Discussion Number   1
NWS National Hurricane Center Miami FL       AL122018
1100 AM AST Sat Sep 22 2018

The area of low pressure located well south of the Cabo Verde
Islands now has a well-defined center and enough organized deep
convection to be considered a tropical cyclone. The initial
intensity is set to 35 kt based on data from recent ASCAT passes
that showed an area of 30-35 kt winds northwest of the center.

Kirk will be moving over SSTs around 27C for the next 36 hours or
so with generally low shear, which should allow for some gradual
strengthening. After that time, the SSTs increase quickly along the
forecast track, but the SHIPS model and global model fields show the
vertical shear increasing, in part due to the very fast low-level
easterly flow. In addition, the GFS and ECMWF global models don't
show much development of the cyclone during the forecast period. As
a result of these factors, little change in strength is forecast
after 48 hours. The NHC forecast is close to the HCCA consensus aid
through 48 hours and is near IVCN afterward.

The initial motion estimate is 280/12, but has the usual uncertainty
for a system in the early stages of development. The cyclone is
expected to be steered very quickly westward at low latitudes with
forward speeds reaching 20-25 kt over the next 72 hours to the south
of a mid-level ridge. Late in the period, some gain in latitude and
a slight decrease in forward speed are shown as a weakness in the
ridge develops to the east of the Lesser Antilles. The initial NHC
track forecast is close to HCCA and a little south of the TVCA
consensus, giving a little more weight to the GFS and ECMWF, which
lie on the south side of the track guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z  8.3N  23.6W   35 KT  40 MPH
12H  23/0000Z  8.8N  25.7W   40 KT  45 MPH
24H  23/1200Z  9.3N  29.6W   45 KT  50 MPH
36H  24/0000Z  9.4N  34.0W   50 KT  60 MPH
48H  24/1200Z  9.6N  38.6W   50 KT  60 MPH
72H  25/1200Z 10.3N  46.8W   50 KT  60 MPH
96H  26/1200Z 11.0N  53.0W   50 KT  60 MPH
120H  27/1200Z 12.5N  58.5W   45 KT  50 MPH

$$
Forecaster Brennan

霧峰追風者

減弱殘餘低壓，不過展望維持50%，有機會再度發展。

2. A tropical wave, the remnants of Kirk, is located about 1300 miles
east of the Windward Islands. This system continues to produce
a large area of showers and thunderstorms, along with winds to gale
force over the northern portion of the wave, while it moves quickly
westward at around 25 mph. This system could redevelop into a
tropical cyclone during the next few days before it encounters
highly unfavorable upper-level winds while it approaches the
Caribbean Sea. For more information on this system, see High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

霧峰追風者

NHC 展望提升至70%，趨向多明尼加。

2. The remnants of Kirk are located about 750 miles east of the
Windward Islands and are moving quickly westward at 20 to 25 mph.
The associated shower and thunderstorm activity has become a little
better organized during the last several hours, however, the
system still appears to lack a closed circulation.  This disturbance
is likely to redevelop into a tropical cyclone during the next day
or two before it moves into an area of highly unfavorable
upper-level winds as it approaches the Caribbean Sea.  Interests in
the Windward and Leeward Islands should monitor the progress of this
disturbance as gusty winds and locally heavy rains are likely over
the next couple of days even if the system does not redevelop into a
tropical cyclone.  For more information on this system, see High
Seas Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

霧峰追風者

09Z 再次升格熱帶風暴，將西行進入加勒比海。

961
WTNT42 KNHC 260844
TCDAT2

Tropical Storm Kirk Discussion Number  10
NWS National Hurricane Center Miami FL       AL122018
500 AM AST Wed Sep 26 2018

Infrared satellite imagery during the past several hours indicates
that deep convection has increased and become better organized near
the center of the remnants of Kirk. In addition, two earlier ASCAT
scatterometer passes between 0000-0100Z indicated that the low-level
center had become a little better defined, and that the inner-core
wind field had contracted, now with a radius of maximum winds (RMW)
of about 40 nmi. Given the continued increase in the amount and
organization of the deep convection, advisories have be re-initiated
on Tropical Storm Kirk. The two ASCAT passes showed peak winds of 38
and 44 kt, so the initial intensity will be a blend of these two
values or 40 kt. An Air Force Reserve reconnaissance aircraft will
be investigating Kirk later this morning to provide more detailed
information on the location and intensity of the tropical storm.

The initial motion estimates is an uncertain 280/16 kt, due to the
lack of a well-defined center to track for the past two days. The
global and regional models, excluding the HWRF model, are in very
good agreement on Kirk moving between west and west-northwest for
the next 72 hours along the south side of a strong Bermuda-Azores
high pressure system anchored across most of the subtropical
Atlantic. After that time, strong shear is forecast to weaken Kirk
into a remnant low, resulting in a more westward motion as the
shallow cyclone will be steered by the low-level easterly trade wind
flow. The official forecast track closely follows the HCCA
corrected-consensus model, and is a little south of the simple
consensus model TVCA due to an apparent northward bias in the HWRF
member.

The current modest west to southwesterly vertical wind shear is
forecast to decrease to less than 10 kt during the next 24 hours,
which should allow for some slight strengthening to occur. After 48
hours when Kirk is forecast to emerge over the eastern Caribbean
Sea, the shear is expected to increase to more then 30 kt, which
should act to displace the deep convection to the east of the
low-level center, resulting in rapid weakening. Kirk is forecast to
degenerate into a remnant low pressure system after 72 hours, but
this could occur a little sooner than indicated in the official
forecast if Kirk moves farther north and into even stronger shear
conditions. The NHC intensity forecast closely follows a blend of
the HCCA, FSSE, and IVCN consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 11.8N  52.7W   40 KT  45 MPH
12H  26/1800Z 12.4N  55.0W   45 KT  50 MPH
24H  27/0600Z 13.2N  57.6W   45 KT  50 MPH
36H  27/1800Z 14.1N  60.0W   45 KT  50 MPH
48H  28/0600Z 14.8N  62.3W   40 KT  45 MPH
72H  29/0600Z 15.7N  67.0W   30 KT  35 MPH
96H  30/0600Z 15.9N  71.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  01/0600Z 16.0N  76.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Stewart