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TROPICAL DEPRESSION NINE DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016
400 AM CDT WED AUG 31 2016
Although clusters of deep convection continue to pulsate near
and to the southeast of the center of the tropical cyclone, there
has been little overall change in organization overnight. A couple
of ASCAT passes since the previous advisory revealed peak winds of
30 kt, so the system remains a 30-kt tropical depression for this
advisory. The upper-level outflow has expanded to the northwest
and north of the cyclone, which suggests that the upper-level wind
pattern is becoming more favorable for strengthening. The SHIPS
model indicates that the shear should remain low during the next day
or so, while the cyclone moves over warm water. This should allow
for strengthening, and the NHC forecast calls for steady
intensification during the next day or so, which is also supported
by the global models. The updated intensity forecast is in good
agreement with the multi-model consensus.
The depresssion has been meandering overnight, but is expected to
begin a northward or northeastward motion later today. A deepening
trough over the southeastern United States should cause the
tropical cyclone to accelerate north-northeastward or northeastward
by tonight. Although the track guidance is in good agreement on
this scenario, the model envelope has shifted slightly westward this
cycle, and the NHC forecast track has been nudged in that
direction.
The new forecast has required the issuance of a Tropical Storm
Warning for a portion of the Florida Gulf coast. The Hurricane
Watch remains in effect since there is still a possibility that
the system could become a hurricane before landfall. It is important
not to focus on the forecast landfall point of this system. Among
other reasons, dangerous storm surge flooding is likely along the
coast well to the east and south of the path of the center.
FORECAST POSITIONS AND MAX WINDS
INIT 31/0900Z 24.5N 88.1W 30 KT 35 MPH
12H 31/1800Z 25.4N 87.8W 40 KT 45 MPH
24H 01/0600Z 26.9N 86.9W 45 KT 50 MPH
36H 01/1800Z 28.4N 85.6W 55 KT 65 MPH
48H 02/0600Z 30.3N 83.6W 55 KT 65 MPH...INLAND
72H 03/0600Z 34.2N 76.8W 60 KT 70 MPH...OVER WATER
96H 04/0600Z 37.0N 70.2W 60 KT 70 MPH
120H 05/0600Z 39.0N 68.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
$$
Forecaster Brown
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