{"id": "1209573686936305666", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-12T09:00:00Z", "msg": "029\nWTPZ44 KNHC 120849\nTCDEP4\n \nTropical Storm Norbert Discussion Number  11\nNWS National Hurricane Center Miami FL       EP142026\n1100 PM HST Fri Sep 11 2026\n \nDeep convection associated with an earlier well-established curved \nband has deteriorated over the past several hours, likely due to \nsome mid-level dry air entrainment. A 0442 UTC scatterometer pass \nindicated peak winds just above 40 kt within the northwest quadrant. \nAdditionally, the latest subjective Dvorak intensity estimate from \nTAFB is T3.0/45 kt, with objective estimates from UW-CIMSS ranging \nfrom 45 to 50 kt. Given these data and the degraded convective \nstructure, the initial intensity is lowered to a generous 50 kt.\n\nThe initial motion is west-northwestward, or 285/8 kt. The track \nguidance has come into much better agreement this cycle and shows \nNorbert continuing generally westward through the weekend as a low- \nto mid-level subtropical ridge remains north of the cyclone. A \ngradual turn toward the west-southwest is then forecast during the \nearly to middle portion of next week. Despite the improved agreement \namong the track guidance this cycle, there has been considerable \nrun-to-run variability, and confidence in the forecast beyond the \nweekend remains lower than normal. The NHC track forecast is largely \nan update of the previous advisory and lies close to the multi-model \nconsensus (HCCA) and Google DeepMind ensemble mean.\n\nEnvironmental conditions remain favorable for some strengthening \nover the weekend, and Norbert is forecast to approach hurricane \nintensity by 24 to 36 h. Thereafter, a gradual weakening trend is \nforecast through the remainder of the period, likely due to a \ncombination of mid-level dry air entrainment and weakening \nupper-level divergence. Simulated satellite imagery from both the \nGFS and ECMWF broadly support this and depict Norbert struggling to \nmaintain organized deep convection as it moves westward to \nwest-southwestward next week. The latest NHC intensity forecast has \nbeen lowered slightly from the previous advisory. It remains above \nthe intensity guidance envelope through the weekend, then trends \ntoward the middle to upper end of the guidance next week. \n\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  12/0900Z 17.1N 127.4W   50 KT  60 MPH\n 12H  12/1800Z 17.4N 128.8W   55 KT  65 MPH\n 24H  13/0600Z 17.8N 130.6W   60 KT  70 MPH\n 36H  13/1800Z 18.1N 132.6W   60 KT  70 MPH\n 48H  14/0600Z 18.4N 134.7W   55 KT  65 MPH\n 60H  14/1800Z 18.4N 137.0W   50 KT  60 MPH\n 72H  15/0600Z 18.3N 139.4W   50 KT  60 MPH\n 96H  16/0600Z 17.4N 144.0W   45 KT  50 MPH\n120H  17/0600Z 15.6N 148.1W   45 KT  50 MPH\n \n"}