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Tropical Depression Fourteen Discussion Number   4
NWS National Hurricane Center Miami FL       AL142017
500 PM AST Fri Sep 15 2017

The depression has become less organized since earlier today with
the center now exposed to the north and northwest of the deep
convection due to northwesterly shear.  Dvorak data T-numbers have
decreased, but an average of the current intensity numbers of
1.5 and 2.5 support maintaining an initial wind speed of 30 kt.
Although the depression is forecast to move over warm water,
moderate northwesterly shear and dry mid-level air to the north
of the cyclone is likely to prevent significant intensification.
However, most of the intensity guidance shows some strengthening and
the depression is forecast to become a tropical storm within the
next day or two.  After that time, increasing westerly shear
produced by a mid- to upper-level trough over the central Atlantic
is expected to weaken the system, and the tropical cyclone is now
forecast to degenerate to a remnant low by day 5.  The new NHC
intensity forecast has been adjusted downward to be in better
agreement with the various intensity consensus aids.

The depression has jogged a little northward this afternoon, but the
long-term motion is west-northwestward at about 10 kt.  The
depression is expected to move westward to west-northwestward to
the south of a narrow ridge over the eastern Atlantic over the
weekend.  By early next week, the ridge is forecast to weaken as a
deep-layer trough becomes established over the east-central
Atlantic.  This should cause the cyclone to gain some latitude
later in the forecast period.  The more northward initial position
has required a northward adjustment of the track forecast, but the
NHC track remains along the southern side of the guidance envelope,
in agreement with the typically reliable HFIP corrected consensus
model.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 12.6N  29.7W   30 KT  35 MPH
 12H  16/0600Z 12.8N  30.8W   30 KT  35 MPH
 24H  16/1800Z 12.9N  32.2W   35 KT  40 MPH
 36H  17/0600Z 13.0N  33.4W   40 KT  45 MPH
 48H  17/1800Z 13.2N  34.7W   40 KT  45 MPH
 72H  18/1800Z 14.6N  38.4W   35 KT  40 MPH
 96H  19/1800Z 16.5N  42.5W   30 KT  35 MPH
120H  20/1800Z 18.5N  46.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown

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