000 WTPZ43 KNHC 120245 TCDEP3 Tropical Depression Thirteen-E Discussion Number 2 NWS National Hurricane Center Miami FL EP132025 900 PM CST Thu Sep 11 2025 The satellite appearance of Thirteen-E has improved some since the previous advisory, with deep convection continuing to burst over or near the estimated low-level center. The latest subjective Dvorak current intensity estimates from TAFB and SAB were 2.5/35 kt and 2.0/30 kt. Meanwhile the objective estimates from UW-CIMSS have ranged from 28 to 35 kt since the previous advisory. Based on a blend of these data, the initial intensity has been held, perhaps conservatively, at 30 kt for this advisory package. The depression is moving to the west-northwest, or 290 degrees, at 10 kt. This general motion is expected to continue for the next couple days, as the cyclone is steered by a mid-level ridge over northern Mexico and Texas. A turn toward the northwest along with a decrease in forward speed is expected over the weekend, as the system moves along the southwestern periphery of the mid-level ridge, with that motion continuing through day 5. The official track forecast lies is very close to the previous advisory, roughly between the corrected consensus HCCA and AI-Driven GDMI track aids. The circulation of Thirteen-E remains very small, with an estimated radius of the outermost closed isobar only 80 n mi, and this may be generous. In the next couple of days, the global models suggest that moderate northeasterly vertical wind shear, along with the proximity to land, should limit the system's ability to intensify significantly, and the intensity forecast only calls for some slow strengthening. Over the weekend, environmental conditions should become more favorable for intensification, as the system will be farther offshore, over very warm water and surrounded by moist mid-level air, while vertical wind shear will drop off to light levels and become aligned with the motion of the cyclone. This should lead to steady strengthening, with the system forecast to become a hurricane by 72 hours. By day 5, cooler sea surface temperatures and drier more stable environment should lead to a weakening trend. The official intensity forecast lies on the higher end of the intensity guidance envelope and closest to the AI-Driven GDMI intensity aid. 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 later tonight, while moving parallel to the southern and southwestern coasts of Mexico. While the strongest winds are expected to remain offshore, gusty winds are possible along portions of the southern and southwestern coast of Mexico from Punta Maldonado through Manzanillo during the next day or so. Interests in these areas should monitor the progress of this system. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 16.0N 99.6W 30 KT 35 MPH 12H 12/1200Z 16.5N 101.3W 35 KT 40 MPH 24H 13/0000Z 17.1N 103.5W 40 KT 45 MPH 36H 13/1200Z 17.6N 105.5W 45 KT 50 MPH 48H 14/0000Z 18.0N 107.1W 50 KT 60 MPH 60H 14/1200Z 18.4N 108.6W 60 KT 70 MPH 72H 15/0000Z 18.9N 109.9W 70 KT 80 MPH 96H 16/0000Z 20.7N 112.6W 70 KT 80 MPH 120H 17/0000Z 23.0N 114.7W 55 KT 65 MPH $$ Forecaster Jelsema (CPHC)
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