老農民版夜神月

  基本資料  
編號　　　　：14 L
擾動編號日期：2019 年 10 月 11 日 19 時
撤編日期　　：2019 年 10 月 15 日 19 時
93L INVEST 191011 0600 38.4N 68.7W ATL 50 997


NHC：30%

1. Showers have become more concentrated this morning near the center
of a non-tropical low pressure system located off the northeastern
and mid-Atlantic coasts of the United States.  This low, which is
currently producing storm-force winds, is expected to continue
meandering off the coast through tonight, producing strong winds,
coastal flooding, heavy rainfall, and rough surf along portions of
the mid-Atlantic and northeastern United States coasts.  Some
additional subtropical or tropical development is possible through
tonight.  Upper-level winds are expected to increase over the system
during the weekend while the low weakens and moves away from the
northeastern United States.  Additional information on this system
can be found in local products and High Seas Forecasts issued by the
National Weather Service.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

-MAX:45,999

Meow

即將命名Melissa

AL, 93, 2019101112,   , BEST,   0, 386N,  697W,  55,  995, SS,

老農民版夜神月

NHC在擾動編號後不久,11/15Z隨即升格93L為副熱帶風暴14L,命名Melissa

000
WTNT44 KNHC 111452
TCDAT4

Subtropical Storm Melissa Discussion Number   1
NWS National Hurricane Center Miami FL       AL142019
1100 AM AST Fri Oct 11 2019

Convection increased near the center of the nor'easter centered
southeast of New England overnight. First-light visible satellite
imagery briefly showed an eye-like feature before the convection
around the immediate center began to weaken. However, a large
convective band still persists over the northern semicircle, and
this structure indicated the system has transitioned to a
subtropical cyclone. The latest Hebert-Poteat classification from
TAFB indicates an initial intensity of 55 kt, and this is also
supported by an earlier scatterometer overpass showing a large area
of winds near 50 kt in the northwest quadrant.

Melissa is currently located underneath an upper-level trough,
resulting in a light shear environment. This trough will begin to
lift northeastward later today, and strong upper-level westerlies
should begin to affect the storm by tonight. This pattern is
expected to cause a weakening trend, and Melissa is forecast to
become post-tropical by Saturday night. The post-tropical cyclone is
then expected to be absorbed by an approaching front in 3 to 4 days.

Melissa is currently embedded in weak steering flow under the upper-
level trough, and little net motion is expected today. Later
tonight, an approaching mid-latitude trough currently crossing
the upper Midwest will begin to force an east-northeastward
motion at a faster forward speed. This motion will continue until
the cyclone is absorbed by the cold front. The NHC track forecast is
closest to the ECMWF ensemble mean.

Ongoing hazards from wind and coastal flooding will continue be
covered by non-tropical products from local National Weather Service
forecast offices.

Gale-force winds that extend well northeastward of Melissa into the
central Atlantic that are not included in the wind radii, since they
are associated with a frontal boundary.

Key Messages:

1. While the nor'easter centered southeast of New England has become
Subtropical Storm Melissa, the expected magnitude of wind and
coastal flooding impacts along portions of the U.S. east coast from
the mid-Atlantic states to southeastern New England has not changed.
For information on these hazards, see products issued by local
National Weather Service forecast offices at weather.gov.

2. Melissa is expected to gradually weaken and begin moving away
from the U.S. east coast by tonight, resulting in a gradual decrease
in wind and coastal flooding impacts.

FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 38.5N  69.6W   55 KT  65 MPH
12H  12/0000Z 38.2N  69.3W   45 KT  50 MPH
24H  12/1200Z 38.4N  67.7W   35 KT  40 MPH
36H  13/0000Z 39.0N  65.1W   30 KT  35 MPH...POST-TROPICAL
48H  13/1200Z 39.9N  61.0W   30 KT  35 MPH...POST-TROPICAL
72H  14/1200Z 41.3N  52.6W   30 KT  35 MPH...POST-TROPICAL
96H  15/1200Z...ABSORBED

$$
Forecaster Latto

老農民版夜神月

NHC判定14L.Melissa已由SS進一步轉化為TS

000
WTNT44 KNHC 130242
TCDAT4

Tropical Storm Melissa Discussion Number   7
NWS National Hurricane Center Miami FL       AL142019
1100 PM AST Sat Oct 12 2019

Satellite imagery indicates that westerly shear is increasing over
Melissa, and the low-level center is now partly exposed at the
western edge of the central convective mass.  However, this has not
yet resulted in a significant decrease in the various subjective
and objective satellite intensity estimates.  The initial intensity
thus remains 45 kt.  There have been significant changes to the
initial 12-ft seas radii for this advisory based on input from the
Ocean Prediction Center.

The initial motion is now 080/12.  Melissa should be steered
generally eastward to east-northeastward in the southern portion of
the mid-latitude westerlies until the system is absorbed by a
frontal zone after 72 h.  There is little change to either the
forecast guidance or the forecast track since the previous advisory,
and the new forecast is in good agreement with the consensus
models.

Westerly shear should continue to increase over Melissa during the
next three days.  In addition, after passing over a patch or eddy
of warm water associated with the Gulf Stream on Sunday, the storm
should encounter much colder water.  This combination should cause
Melissa to weaken, and it is expected to become a remnant low after
24 h.  While the forecast philosophy is unchanged from the previous
forecast, the new intensity forecast is tweaked slightly to keep
Melissa a tropical storm through 24 h based on the expected passage
over the warm water eddy.

Ongoing hazards from coastal flooding will continue to be covered by
non-tropical products from local National Weather Service forecast
offices.

Key Messages:

1. Although Melissa is forecast to weaken and move away from the
U.S. east coast, minor to moderate coastal flooding is still
expected along portions of the U.S. Mid-Atlantic and southeastern
coasts around times of high tide for the remainder of the weekend.
For more information, see products issued by local National Weather
Service forecast offices at weather.gov.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 38.6N  64.0W   45 KT  50 MPH
12H  13/1200Z 39.2N  61.5W   40 KT  45 MPH
24H  14/0000Z 40.2N  57.6W   35 KT  40 MPH
36H  14/1200Z 41.1N  53.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
48H  15/0000Z 42.0N  47.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
72H  16/0000Z 42.2N  35.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  17/0000Z...DISSIPATED

$$
Forecaster Beven