{"id": "1214316025134841863", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-29T03:00:00Z", "msg": "987\nWTPZ43 KNHC 290250\nTCDEP3\n \nTropical Storm Rachel Discussion Number   8\nNWS National Hurricane Center Miami FL       EP182026\n900 PM CST Mon Sep 28 2026\n \nThe satellite-observed structure of Rachel has improved this \nevening. While the storm is still clearly feeling the effects of \nnortherly shear, proxy-visible and infrared satellite images show \nthe low-level center is tucked underneath the northern side of the \ncold dense overcast. TAFB also noted an improvement in the satellite \nstructure of Rachel with their latest T3.0 Dvorak classification, \nand the various UW-CIMSS objective estimates generally range from \n44-54 kt. Based on a blend of these estimates, the initial intensity \nis set at 50 kt.\n\nRachel is moving west-northwestward (300/9 kt) along the southwest \nside of a mid-level ridge over northern Mexico. A deep-layer trough \nover the southwestern United States is expected to move eastward \nduring the next couple of days, which should erode the ridge and \ncause Rachel to turn northwestward at a slower forward speed within \nweaker steering currents through midweek. By late week, the trough \nis forecast to lift out and the ridge should become reestablished to \nthe north, with Rachel expected to resume a west-northwestward \nmotion. Overall, the track model guidance trended slightly faster \nthis cycle, and the NHC forecast has been adjusted to fall between \nthe latest simple (TVCN) and corrected (HCCA) consensus aids.\n \nIn general, the models agree that Rachel should intensify over very \nwarm SSTs (29-30 deg C) with abundant mid-level moisture and a \ndivergent upper-level environment. Moderate vertical wind shear \nappears to be the only limiting factor, though it is forecast to \ngradually decrease through midweek. Since the tropical storm is \nsheared and currently lacks an inner core, only gradual \nstrengthening is forecast tonight. Thereafter, there is fairly large \nspread in the intensity guidance, with some models including Google \nDeepMind, COAMPS-TC, and HCCA showing Rachel reaching major \nhurricane status. The updated NHC intensity forecast is not as \naggressive as these models but has been raised from the previous \nprediction, slightly higher than the simple consensus (IVCN) but \nstill well below the latest HCCA and GDMI aids. The NHC forecast \nlevels off in the 60-120 h time frame based on mixed signals in the \nguidance, perhaps a result of Rachel encountering some cooler waters \nleft behind in the wake of Hurricane Polo.\n \n \nKey Messages:\n \n1. Although the core of Rachel is forecast to remain offshore of \nMexico, tropical-storm-force winds are expected along a portion of \nthe coast of southwestern Mexico in the Tropical Storm Warning area \non Tuesday. Tropical storm conditions are possible in the watch \narea Tuesday night or on Wednesday.\n \n2. Outer bands from Rachel will bring locally heavy rainfall to \nportions of coastal southwest Mexico through Thursday. This rainfall \nmay produce areas of flooding and mudslides, especially in areas of \nsteep terrain.\n \n3. Large waves could produce life-threatening surf and rip current\nconditions along portions of the southwestern coast of Mexico during\nthe next several days.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  29/0300Z 14.5N 102.9W   50 KT  60 MPH\n 12H  29/1200Z 15.2N 104.3W   55 KT  65 MPH\n 24H  30/0000Z 16.5N 105.8W   65 KT  75 MPH\n 36H  30/1200Z 17.9N 107.0W   75 KT  85 MPH\n 48H  01/0000Z 18.9N 107.8W   80 KT  90 MPH\n 60H  01/1200Z 19.5N 108.5W   85 KT 100 MPH\n 72H  02/0000Z 19.9N 109.1W   85 KT 100 MPH\n 96H  03/0000Z 20.4N 110.1W   80 KT  90 MPH\n120H  04/0000Z 20.9N 111.4W   80 KT  90 MPH\n \n"}