{"id": "1204194832438591490", "title": "Tropical Cyclone Discussion", "adv_date": "2026-08-24T09:00:00Z", "msg": "052\nWTPZ44 KNHC 240851\nTCDEP4\n \nTropical Storm Iselle Discussion Number   4\nNWS National Hurricane Center Miami FL       EP092026\n200 AM PDT Mon Aug 24 2026\n \nIselle is being affected by northwesterly shear, with much of the \ndeep convection displaced to the south and east of the center. Over \nthe past several hours, the convective structure has evolved, with \ncurved banding becoming increasingly established around the center. \nThe latest Dvorak intensity estimate from TAFB at 0600 UTC was \n3.0/45 kt; however, recent objective intensity estimates from \nUW-CIMSS have increased and range from 43-59 kt. Given the improved \nbanding evident on satellite imagery and the upward trend in \nobjective intensity estimates, the initial intensity is set at 50 kt \nfor this advisory. \n\nThe tropical storm is moving northwestward around 10 kt, steered by \na mid-level ridge centered over the southwestern United States. \nIselle is forecast to turn toward the west-northwest as the ridge \nexpands westward into the eastern Pacific, and this general motion \nis expected through much of this week. The latest NHC forecast is \nvery similar to the previous advisory and lies near the middle of \nthe track guidance envelope, closest to the HFIP Corrected Consensus \n(HCCA) and the Google DeepMind (GDMI) model. There is considerable \nspread among the guidance during the latter portion of the forecast \nperiod, resulting in slightly below-average confidence in the track \nforecast. \n\nIselle is moving over warm waters around 29-30 C and remains within \na fairly moist mid-level environment, which should support gradual \nstrengthening during the next 12-24 h. The latest NHC forecast \nbrings Iselle to hurricane strength during this period, near the \nupper end of the intensity guidance, and is consistent with HCCA and \nGDM. Beyond 24 h, increasing wind shear, cooler waters and \nprogressively drier mid-level air are expected to lead to gradual \nweakening from Tuesday through the remainder of the week. The ECMWF \nand GFS simulated satellite imagery suggest that Iselle may struggle \nto maintain organized convection by late this week, raising the \npossibility that the cyclone could become post-tropical earlier than \ncurrently forecast. \n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  24/0900Z 17.8N 116.2W   50 KT  60 MPH\n 12H  24/1800Z 19.0N 117.4W   60 KT  70 MPH\n 24H  25/0600Z 20.1N 118.9W   65 KT  75 MPH\n 36H  25/1800Z 20.9N 120.7W   60 KT  70 MPH\n 48H  26/0600Z 21.5N 122.5W   55 KT  65 MPH\n 60H  26/1800Z 21.9N 124.4W   50 KT  60 MPH\n 72H  27/0600Z 22.4N 126.3W   45 KT  50 MPH\n 96H  28/0600Z 23.1N 130.1W   35 KT  40 MPH\n120H  29/0600Z 23.9N 134.1W   30 KT  35 MPH...POST-TROP/REMNT LOW\n \n"}