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Potential Tropical Cyclone SEVEN


Potential Tropical Cyclone Seven Discussion Number   3...Corrected
NWS National Hurricane Center Miami FL       AL072018
500 AM EDT Mon Sep 03 2018

Corrected motion in second paragraph

The system is gradually becoming better organized with some
increased convective banding features.  However, surface and radar
data suggest that a well-defined center of circulation has not yet
formed.  The initial intensity is set at 25 kt in agreement with the
latest Dvorak estimates from TAFB and SAB.  An Air Force Reserve
Unit Hurricane Hunter aircraft is scheduled to investigate the
system later this morning, and should provide a better estimate of
its intensity and structure.  Global model predictions show
a closed circulation forming within 12 to 24 hours, so the official
forecast calls for tropical cyclone status later today.  Although
the system should move over the very warm waters of the eastern and
north-central Gulf of Mexico during the next 36 hours, the model
guidance is not very aggressive about intensification.  This may be
due to some moderate shear as indicated by the SHIPS model output.
The official intensity forecast is similar to the previous one and
at the upper end of the numerical guidance suite.

The disturbance appears to have picked up some forward speed, and is
now moving at around 300/14 kt.  A west-northwestward to
northwestward motion is likely, along the southwestern periphery of
a mid-level anticyclone, until landfall along the northern Gulf
coast.  The official track forecast is close to the dynamical model
consensus and is just slightly to the right of and faster than the
previous one.

Given the proximity of the 36-hour forecast point to the coast, it
is time to change the Tropical Storm Watch to a Warning.

Key Messages:

1. Potential Tropical Cyclone Seven will bring heavy rainfall and
gusty winds to portions of the Bahamas, South Florida, and the
Florida Keys today, and interests in those areas should
monitor the progress of this system.

2. A Tropical Storm Warning has been issued for portions of the
central Gulf Coast, and tropical storm conditions are expected in
those areas beginning late Tuesday.  Heavy rainfall from this
system will affect portions of the central Gulf Coast over the next
few days, including areas that have already received heavy rainfall
from a different weather system.  Interests in these areas should
monitor products from their local National Weather Service office.

3. Users should be aware that forecast uncertainty for potential
tropical cyclones is generally larger than that for tropical
cyclones, especially beyond 48-72 hours.


INIT  03/0900Z 24.5N  80.2W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  03/1800Z 25.7N  82.1W   30 KT  35 MPH
 24H  04/0600Z 27.2N  84.8W   35 KT  40 MPH
 36H  04/1800Z 28.8N  87.4W   40 KT  45 MPH
 48H  05/0600Z 30.4N  89.7W   50 KT  60 MPH
 72H  06/0600Z 33.0N  92.7W   30 KT  35 MPH...INLAND
 96H  07/0600Z 34.0N  95.0W   25 KT  30 MPH...INLAND
120H  08/0600Z 35.5N  96.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

Forecaster Pasch