000 WTPZ42 KNHC 162033 TCDEP2 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