{"id": "1215023483516977159", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-01T15:00:00Z", "msg": "438\nWTPZ43 KNHC 011448\nTCDEP3\n \nHurricane Rachel Discussion Number  18\nNWS National Hurricane Center Miami FL       EP182026\n800 AM MST Thu Oct 01 2026\n \nSatellite images show that Rachel continues to produce deep \nconvection with cold cloud tops near -80 to -85C. GLM lightning data \nalso depicts increased lightning activity in the inner core of the \nstorm. An AMSR3 microwave pass that arrived shortly after the \nprevious advisory indicated that the low-level center was slightly \nfarther east within the deep convection and, while there still was \nsome tilt between the low- and mid-level core, the inner structure \nis becoming better defined, particularly on the southern side of the \ncirculation. Satellite intensity estimates have increased slightly \nand vary depending on where the low-level center is placed. The \nsubjective Dvorak satellite intensity estimate was Data-T 5.0/90 kt \nwith a Final-T of 4.5/77 kt, and the last three DMINT estimates \nusing various microwave images over the past several hours ranged \nbetween 88-91 kt. Given the improved structure in the microwave data \nand current satellite trends, the initial intensity is raised to 90 \nkt for this advisory.\n \nThe system continues to move west-northwestward, or 295/5 kt, and \nthis motion is expected to continue at a slightly slower forward \nspeed over the next couple of days. As a trough over the western \nU.S. lifts northeastward, a mid-level ridge will build to the north \nof Rachel, and a westward motion at an increased forward speed is \nexpected through the end of the forecast period. There are some \nalong-track differences in the guidance this cycle regarding when \nthe westward acceleration begins, with the GDMI and HCCA moving \ninitially slower than the global models. The NHC track forecast has \nbeen slowed down slightly in the short term, and trends toward the \nHCCA and GDMI aids.\n \nEnvironmental conditions remain generally favorable for \nstrengthening, with warm sea surface temperatures and plenty of \nmid-level moisture. The only inhibiting factor has been the wind \nshear that has kept Rachel's strengthening rate more gradual to \nsteady. Although the wind shear had been forecast to lessen, it has \nnot done so, and the latest SHIPS forecast now keeps the shear \nmoderate over the next two days or so. Given the current structure, \nthe NHC forecast indicates continued strengthening for the next day \nor so, which lies above the model guidance. In about 2-3 days, wind \nshear is forecast to decrease though the hurricane should encounter \ndrier mid-level air while the system moves almost parallel to the \n27C isotherm.  These factors should cause a weakening trend but how \nfast that weakening occurs will be highly dependent on the structure \nof the system. Additionally, with weak shear and the hurricane \nparalleling the 27C isotherm, the structure can sometimes become \nannular, moderating the weakening rate. The latest NHC intensity \nforecast trends back toward the HCCA intensity aid during the latter \npart of the forecast period with gradual weakening, although there \nremains uncertainty at that time range.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  01/1500Z 19.6N 109.6W   90 KT 105 MPH\n 12H  02/0000Z 19.7N 110.1W   95 KT 110 MPH\n 24H  02/1200Z 19.8N 110.8W  100 KT 115 MPH\n 36H  03/0000Z 20.0N 111.5W  105 KT 120 MPH\n 48H  03/1200Z 20.1N 112.5W  100 KT 115 MPH\n 60H  04/0000Z 20.3N 113.6W   95 KT 110 MPH\n 72H  04/1200Z 20.4N 114.7W   90 KT 105 MPH\n 96H  05/1200Z 20.5N 117.2W   85 KT 100 MPH\n120H  06/1200Z 20.6N 120.3W   80 KT  90 MPH\n \n"}