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Tropical Depression Fifteen-E Discussion Number 6
NWS National Hurricane Center Miami FL EP152017
800 PM PDT Tue Sep 12 2017
Although deep convection associated with the depression has
increased since the previous advisory, it remains displaced
to the west of the center due to about 15 kt of easterly wind
shear. The initial intensity is held at 30 kt, in agreement with a
blend of the Dvorak classifications from TAFB/SAB and ADT values
from CIMSS at the University of Wisconsin.
The current wind shear affecting the depression is expected to
persist overnight, so little change in intensity is forecast during
that time. Thereafter, the global models show the upper-level wind
pattern becoming a little less hostile over the depression. This
slightly more favorable atmospheric environment combined with warm
SSTs should allow the system to strengthen a little. Earlier
model solutions showed the depression interacting with a developing
system to its east, but the guidance is showing less interaction
now. Based on the model trends and the expected environmental
conditions, the NHC intensity forecast no longer calls for the
depression to become a remnant low, and instead predicts the system
to remain a tropical cyclone during the next 5 days. This forecast
is in good agreement with the latest models, except at day 5 where
it lies on the low side of the guidance.
Satellite fixes suggest that the depression is moving just south of
due west, 265 degrees, at 11 kt. A continued west motion, but at
a much slower pace is expected during the next few days as a
mid-level ridge to the north of the cyclone weakens. By the end of
the forecast period, the system could become stationary when it is
expected to be embedded in very weak steering currents. The NHC
track forecast is a little faster than the previous one to come in
line with the latest model guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 13/0300Z 15.4N 118.6W 30 KT 35 MPH
12H 13/1200Z 15.2N 119.7W 30 KT 35 MPH
24H 14/0000Z 15.3N 121.2W 35 KT 40 MPH
36H 14/1200Z 15.5N 122.7W 35 KT 40 MPH
48H 15/0000Z 15.6N 123.9W 35 KT 40 MPH
72H 16/0000Z 15.5N 125.1W 40 KT 45 MPH
96H 17/0000Z 15.5N 126.0W 40 KT 45 MPH
120H 18/0000Z 15.6N 126.6W 40 KT 45 MPH
$$
Forecaster Cangialosi
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