Potential Tropical Cyclone Nine Discussion Number 1
NWS National Hurricane Center Miami FL AL092019
500 PM EDT Thu Sep 12 2019

The disturbance in the southeastern Bahamas has not developed a
closed circulation yet, but the cloud pattern is gradually becoming
better organized. An Air Force plane is currently approaching the
disturbance, and will give NHC more details on the structure of the
system. Advisories are being initiated on this system as a
Potential Tropical Cyclone to allow for the issuance of a tropical
storm warning for a portion of the northwest Bahamas after
consultation with the meteorological service of that country.

The system is still under the influence of strong shear caused by an
upper-level low in the Gulf of Mexico. As the disturbance moves away
from the upper low, conditions are expected to be a little more
conducive for development as indicated in the intensity forecast.
With the exception of the GFS, which forecasts a vigorous trough
crossing Florida into the Gulf of Mexico, the remainder of the
global models develop a tropical cyclone near the northwestern
Bahamas and move it as an intensifying system very close to the east
coast of Florida. The NHC forecast opted for the solution of these
latter models, however, it is emphasized that given the model
discrepancy, both the track and intensity forecasts are highly
uncertain, more than usual I would say.

Key Messages:

1. The disturbance is expected to become a tropical storm and bring
tropical storm force winds to portions of the northwest Bahamas
within 36 hours. As a result, advisories have been initiated on
Potential Tropical Cyclone Nine. Note that forecast uncertainty for
these disturbances is generally larger than for tropical cyclones,
especially beyond 48-72 hours.

2. The system is expected to bring tropical-storm-force winds and
heavy rainfall to portions of the northwest Bahamas on Friday and
Saturday. Significant storm surge is not expected in the northwest
Bahamas from this system. Residents there should follow any advice
given by local officials.

3. The system could bring tropical-storm-force winds and rainfall
to portions of the Florida east coast over the weekend. Residents
there should monitor the progress of this system.


FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 23.7N 74.8W 25 KT 30 MPH...POTENTIAL TROP CYCLONE
12H 13/0600Z 24.5N 76.0W 25 KT 30 MPH
24H 13/1800Z 25.5N 77.2W 30 KT 35 MPH...TROPICAL CYCLONE
36H 14/0600Z 26.5N 78.9W 40 KT 45 MPH
48H 14/1800Z 27.5N 80.2W 45 KT 50 MPH
72H 15/1800Z 30.0N 82.0W 30 KT 35 MPH...INLAND
96H 16/1800Z 31.0N 82.0W 25 KT 30 MPH...INLAND
120H 17/1800Z 31.5N 80.0W 30 KT 35 MPH...OVER WATER


Edited: 09/18/2019 at 05:02 AM by Central Floridave