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Tropical Depression Tara Discussion Number  10
NWS National Hurricane Center Miami FL       EP222018
400 PM CDT Tue Oct 16 2018

Interaction with the mountainous terrain of southwestern Mexico,
along with some modest southeasterly wind shear and drier mid-level
air, have combined to weaken tiny Tara. The tropical cyclone still
has a tight spiral convective banding signature in recent microwave
imagery. However, the northern portion of the small circulation
is clearly interacting with the coastal mountains, and surface
observations from Manzanillo, Mexico (MMZO) since 1500Z have
indicated a veering wind from northeast to southeast at a steady 20
kt. The position and intensity were based in part on the MMZO
observations and a 1541Z ScatSat pass, but mainly on a 1630Z AMSU
microwave satellite overpass.

The initial motion estimate is 325/02 kt. Surface wind direction
data from MMZO indicate that Tara passed west of that station's
longitude around 1530Z. Visible and scatterometer satellite data
indicate that a surface/low-level trough lies northwest-to-southeast
just offshore the southwestern coast of Mexico, and the tiny
tropical cyclone is expected to drift slowly northwestward along the
trough axis for the next 12-24 hours as per most of the new 12Z
global models. The HWRF hangs on to a weak low until about 48 hours
or so, with dissipation occurring quickly thereafter. The official
forecast lies between these two scenarios, keeping Tara as a remnant
low through 36 hours. However, if the small cyclone doesn't move
away from Mexico within the next 12 hours, then degeneration into a
remnant low and eventual dissipation could occur sooner than
forecast due to continued intrusions of drier mid-level air and
interaction with the mountainous terrain of southwestern Mexico.

Regardless of the exact track or intensity of Tara or its remnants,
heavy rainfall will continue to be a threat along the immediate
coast of southwestern Mexico for the next day or so due to the
system's slow motion, and life-threatening flash flooding will be
possible in mountainous areas.

FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 19.0N 105.0W   30 KT  35 MPH
 12H  17/0600Z 19.2N 105.3W   30 KT  35 MPH
 24H  17/1800Z 19.5N 105.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  18/0600Z 19.7N 106.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  18/1800Z...DISSIPATED

$$
Forecaster Stewart

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