000 WTPZ43 KNHC 120836 TCDEP3 Tropical Depression Thirteen-E Discussion Number 3 NWS National Hurricane Center Miami FL EP132025 300 AM CST Fri Sep 12 2025 The depression remains poorly organized tonight, with only small areas of convection bursting to the west of the estimated low-level center. Recent scatterometer data and surface observations indicate the circulation remains very small. While believable scatterometer winds up to about 30 kt were noted offshore in the northern semicircle of the circulation, observations from the Acapulco International Airport indicated these winds did not reach the coast when the system made its closest approach earlier tonight. Since the overall satellite presentation has slightly worsened since the earlier scatterometer pass, the initial intensity is held at 30 kt. The initial motion is west-northwestward (295/10 kt), and the system should maintain this heading during the next couple of days while being steered by a mid-level ridge centered over northern Mexico. Later this weekend through early next week, the system is forecast to move toward the northwest as it rounds the southwestern portion of the steering ridge. The NHC track forecast through 60 h has been nudged slightly northward this cycle, in agreement with the latest multi-model consensus aids. In the near term, only modest strengthening is forecast due to the system's close proximity to land. Some models, including the GFS and ECMWF, completely lose the circulation later today. But if the system remains offshore and survives its close passage to the southwestern coast of Mexico, the environment should become somewhat more favorable for strengthening with weaker shear conditions over warm waters. Overall, the intensity guidance trended much lower this cycle. The updated NHC intensity forecast reflects this trend, but remains on the high end of the guidance envelope. Future downward adjustments may be necessary, and it cannot be ruled out that the system dissipates before the end of the 5-day forecast period. Key Messages: 1. Heavy rainfall associated with Tropical Depression Thirteen-E will impact southern and southwestern Mexico through Sunday, which could result in flash flooding, particularly in areas of higher terrain. 2. The depression is forecast to become a tropical storm today while moving parallel to the southwestern coast of Mexico. While the strongest winds are expected to remain offshore, gusty winds are possible along portions of the southwestern coast of Mexico from Acapulco to Manzanillo during the next day or so. Interests in these areas should monitor the progress of this system. FORECAST POSITIONS AND MAX WINDS INIT 12/0900Z 16.5N 100.8W 30 KT 35 MPH 12H 12/1800Z 17.0N 102.5W 35 KT 40 MPH 24H 13/0600Z 17.6N 104.6W 35 KT 40 MPH 36H 13/1800Z 18.1N 106.5W 40 KT 45 MPH 48H 14/0600Z 18.6N 108.1W 45 KT 50 MPH 60H 14/1800Z 19.0N 109.6W 55 KT 65 MPH 72H 15/0600Z 19.5N 110.9W 60 KT 70 MPH 96H 16/0600Z 21.0N 113.0W 60 KT 70 MPH 120H 17/0600Z 23.0N 115.5W 45 KT 50 MPH $$ Forecaster Reinhart