ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Tropical Depression Seventeen-E Discussion Number 1 NWS National Hurricane Center Miami FL EP172021 1000 AM CDT Fri Oct 22 2021 Over the past 24 h, the convective organization has steadily increased in association with the area of low pressure to the southwest of southern Mexico. Overnight, an ASCAT overpass showed that the system still lacked a well-defined low-level center. However, since that time visible satellite imagery reveals that the disturbance has become much better organized and that a tropical cyclone has formed. The most recent subjective Dvorak intensity estimates from both TAFB and SAB were T-2.0/30 kt, and therefore 30 kt is the initial advisory intensity. The tropical depression is moving 280/9 kt to the south of a mid-tropospheric ridge. A deep-layer trough is forecast to dig southeastward toward the western United States this weekend and early next week, which should create a weakness in the ridge to the north of the cyclone. This would cause the depression to slow its forward motion and turn northwest or north-northwest towards this weakness. There is a fair amount of spread in the model guidance beyond 24 h, as the various models have different solutions as to how abrupt of a turn to the right the cyclone will make in response to the change in the steering flow. The NHC track forecast is near the HFIP corrected consensus, HCCA, and the TVCE guidance. Based on the current NHC forecast track, the cyclone would be nearing the coast of southwestern Mexico in 72 h, and inland by 96 h. However, due to the larger-than-normal model spread beyond 24 h, that portion of the forecast track is not particularly of high confidence. The cyclone is expected to be within an ideal environment for strengthening over the next couple of days, with very little vertical wind shear, a moist airmass, and sea surface temperatures near 30 degrees C. Therefore, steady intensification is indicated by all of the model guidance through 60 h. There is some weakening indicated by the models at 72 h, around the time the system would be nearing the coast of Mexico, which could be due to some dry air entraining into the cyclone's circulation. The NHC intensity forecast is near the IVCN consensus solution through 72 h but below HCCA. Beyond landfall, the intensity forecast is near the Decay-SHIPS prediction. It should be noted that the SHIPS Rapid Intensification guidance indicates a greater than 60 percent chance of a 55-kt increase in strength over the next 60 h and 65 kt over the next 72 h. Based on the forecast track, intensity, and wind radii, Tropical Storm or Hurricane Watches may be issued for a portion of the southwestern Mexico coast as early as tonight. FORECAST POSITIONS AND MAX WINDS INIT 22/1500Z 12.7N 100.5W 30 KT 35 MPH 12H 23/0000Z 13.0N 101.3W 40 KT 45 MPH 24H 23/1200Z 13.9N 101.9W 50 KT 60 MPH 36H 24/0000Z 14.6N 102.3W 65 KT 75 MPH 48H 24/1200Z 15.3N 102.7W 75 KT 85 MPH 60H 25/0000Z 16.2N 103.1W 80 KT 90 MPH 72H 25/1200Z 17.3N 103.5W 75 KT 85 MPH 96H 26/1200Z 19.8N 104.0W 35 KT 40 MPH...INLAND 120H 27/1200Z 22.0N 104.3W 20 KT 25 MPH...POST-TROP/INLAND $$ Forecaster Latto NNNN