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TROPICAL DEPRESSION NINE DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092015
1100 AM AST THU SEP 17 2015

The center of the depression can be seen in visible imagery exposed
to the west of what remains of the deep convection, due to about
25 kt of shear over the cyclone as indicated by UW-CIMSS satellite
analyses. The initial intensity remains 30 kt based on the latest
Dvorak estimates from TAFB and SAB. The environmental conditions
become even less favorable with time, with the shear forecast to
continue while the cyclone moves into an increasingly dry
environment. These factors should result in slow weakening, and the
NHC forecast shows the depression becoming a remnant low by 36
hours, with dissipation expected in 4 to 5 days.

The initial position of the depression is a little south of that
from the previous advisory, as the partially decoupled low-level
circulation is moving northwestward at about 5 kt. The track
forecast philosophy has not changed, as the weakening cyclone should
move generally northwestward for the next 24 to 36 hours and then
turn west-northwestward as a shallower system. The new NHC track is
in best agreement with the GFS and shallow BAM and lies south of the
multi-model consensus. This forecast is similar to the previous
one updated for the initial position and motion. There are a couple
of alternate scenarios, however. The depression or its remnants
could merge with the disturbance to its east as seen in the UKMET
solution or survive as its own entity a little longer as indicated
by the latest ECMWF forecast. However, the NHC track forecast
continues to favor a solution with a weakening cyclone that remains
separate from the disturbance to the east and dissipates by 5 days.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 16.1N  45.2W   30 KT  35 MPH
 12H  18/0000Z 16.8N  45.8W   30 KT  35 MPH
 24H  18/1200Z 17.8N  46.8W   30 KT  35 MPH
 36H  19/0000Z 18.8N  47.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  19/1200Z 19.5N  49.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  20/1200Z 20.5N  51.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  21/1200Z 22.0N  54.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  22/1200Z...DISSIPATED

$$
Forecaster Brennan

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