000 WTPZ42 KNHC 141500 TCDEP2 Tropical Depression Twenty-Two-E Discussion Number 1 NWS National Hurricane Center Miami FL EP222018 1000 AM CDT Sun Oct 14 2018 A small low pressure system that the NHC has been tracking for the past couple of days has finally acquired enough organized convection to be designated a tropical depression, which is located less than 100 nmi off the southwestern coast of Mexico. Cloud tops near the center have recently been as cold as -90C, and satellite intensity estimates are T1.5/25 kt from both TAFB and SAB. The initial intensity is set at 30 kt based on an earlier OSCAT/ScatSat scatterometer pass that had a few uncontaminated wind vectors located just north of a well-defined low-level circulation center, which is similar to yesterday's ASCAT passes. The initial motion estimate is 295/05 kt. The small cyclone is forecast by the global and regional models to move only slowly westward to southwestward at less than 5 kt for the new few days due to the system being caught in a break in the subtropical ridge that extends from central Mexico southwestward into the eastern Pacific. By days 4 and 5, the ridge is forecast to build westward to the north of the system, acting to nudge the cyclone westward at a slightly faster forward speed. The NHC forecast track lies between the consensus models TVCE and HCCA. The environment is expected to be somewhat conducive for gradual strengthening of the cyclone throughout the forecast period. The statistical-dynamical models SHIPS and LGEM aren't overly enthused with intensifying the system, but that is mainly due to the high shear values calculated from the very poleward TABM beta-advection model, which recurves the cyclone into strong mid-latitude flow on days 4 and 5. In contrast, the HWRF model keeps the system farther south and gradually develops the cyclone into a hurricane by 72 h, and then continues with slight strengthening beyond that time. Given that the shear is expected to only be around 10 kt from an easterly to southeasterly direction and water temperatures near 30 deg C beneath the small cyclone, some gradual strengthening appears to be plausible with only some slight land interaction being the primary modulating factor until the system moves farther away from Mexico in about 72 h. Based on the small size of the circulation and its projected motion away from Mexico, tropical storm warnings and watches are not required at this time. However, only a slight deviation to the right of the forecast track would bring stronger winds closer to the coast, which would require the issuance of a tropical storm warning. Regardless, heavy rainfall will be the primary threat along the coast of southwestern Mexico due to the system's slow motion, and flash flooding will be a possibility in mountainous areas. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 17.0N 102.8W 30 KT 35 MPH 12H 15/0000Z 17.2N 103.6W 35 KT 40 MPH 24H 15/1200Z 17.2N 103.8W 35 KT 40 MPH 36H 16/0000Z 17.0N 103.8W 40 KT 45 MPH 48H 16/1200Z 16.6N 103.6W 45 KT 50 MPH 72H 17/1200Z 16.3N 104.4W 60 KT 70 MPH 96H 18/1200Z 16.5N 105.9W 70 KT 80 MPH 120H 19/1200Z 16.9N 107.5W 80 KT 90 MPH $$ Forecaster Stewart