Tropical Storm Rachel Forecast Discussion
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000 WTPZ43 KNHC 290250 TCDEP3 Tropical Storm Rachel Discussion Number 8 NWS National Hurricane Center Miami FL EP182026 900 PM CST Mon Sep 28 2026 The satellite-observed structure of Rachel has improved this evening. While the storm is still clearly feeling the effects of northerly shear, proxy-visible and infrared satellite images show the low-level center is tucked underneath the northern side of the cold dense overcast. TAFB also noted an improvement in the satellite structure of Rachel with their latest T3.0 Dvorak classification, and the various UW-CIMSS objective estimates generally range from 44-54 kt. Based on a blend of these estimates, the initial intensity is set at 50 kt. Rachel is moving west-northwestward (300/9 kt) along the southwest side of a mid-level ridge over northern Mexico. A deep-layer trough over the southwestern United States is expected to move eastward during the next couple of days, which should erode the ridge and cause Rachel to turn northwestward at a slower forward speed within weaker steering currents through midweek. By late week, the trough is forecast to lift out and the ridge should become reestablished to the north, with Rachel expected to resume a west-northwestward motion. Overall, the track model guidance trended slightly faster this cycle, and the NHC forecast has been adjusted to fall between the latest simple (TVCN) and corrected (HCCA) consensus aids. In general, the models agree that Rachel should intensify over very warm SSTs (29-30 deg C) with abundant mid-level moisture and a divergent upper-level environment. Moderate vertical wind shear appears to be the only limiting factor, though it is forecast to gradually decrease through midweek. Since the tropical storm is sheared and currently lacks an inner core, only gradual strengthening is forecast tonight. Thereafter, there is fairly large spread in the intensity guidance, with some models including Google DeepMind, COAMPS-TC, and HCCA showing Rachel reaching major hurricane status. The updated NHC intensity forecast is not as aggressive as these models but has been raised from the previous prediction, slightly higher than the simple consensus (IVCN) but still well below the latest HCCA and GDMI aids. The NHC forecast levels off in the 60-120 h time frame based on mixed signals in the guidance, perhaps a result of Rachel encountering some cooler waters left behind in the wake of Hurricane Polo. Key Messages: 1. Although the core of Rachel is forecast to remain offshore of Mexico, tropical-storm-force winds are expected along a portion of the coast of southwestern Mexico in the Tropical Storm Warning area on Tuesday. Tropical storm conditions are possible in the watch area Tuesday night or on Wednesday. 2. Outer bands from Rachel will bring locally heavy rainfall to portions of coastal southwest Mexico through Thursday. This rainfall may produce areas of flooding and mudslides, especially in areas of steep terrain. 3. Large waves could produce life-threatening surf and rip current conditions along portions of the southwestern coast of Mexico during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 14.5N 102.9W 50 KT 60 MPH 12H 29/1200Z 15.2N 104.3W 55 KT 65 MPH 24H 30/0000Z 16.5N 105.8W 65 KT 75 MPH 36H 30/1200Z 17.9N 107.0W 75 KT 85 MPH 48H 01/0000Z 18.9N 107.8W 80 KT 90 MPH 60H 01/1200Z 19.5N 108.5W 85 KT 100 MPH 72H 02/0000Z 19.9N 109.1W 85 KT 100 MPH 96H 03/0000Z 20.4N 110.1W 80 KT 90 MPH 120H 04/0000Z 20.9N 111.4W 80 KT 90 MPH $$ Forecaster Reinhart