{"id": "1217289495454777351", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-09T15:00:00Z", "msg": "178\nWTNT44 KNHC 091454\nTCDAT4\n \nHurricane Isaias Discussion Number  12\nNWS National Hurricane Center Miami FL       AL092026\n1000 AM CDT Fri Oct 09 2026\n \nAn Air Force Reserve Hurricane Hunter aircraft currently \ninvestigating Isaias measured a peak 700-mb flight-level wind of \n120 kt within the eastern eyewall a few hours ago, prompting an \nupgrade of the hurricane to major hurricane status with estimated \nsurface winds of 105 kt. Based on the last several dropsondes \nreleased in the eye, the central pressure appears to have leveled \noff around 959 mb. On the last pass through the eastern eyewall, \njust about a half hour ago, the plane measured a flight-level \nwind of 111 kt, suggesting that the peak winds may have also \nleveled off. The eye itself has become cloud filled in visible \nsatellite imagery, but it is now moving into range of several \nWSR-88D radars along the northern Gulf coast.\n\nStrong deep-layer shear has definitely increased as forecast, with \nvarious analyses now showing 30-40 kt out of the southwest. \nHowever, the shear vector is nearly aligned with the storm's \nmotion, which limits its adverse effects, and upper-level \ndivergence is also increasing over the hurricane. This setup has \nlikely allowed the hurricane to intensify this morning, and the \nhurricane regional models (HAFS-A, HAFS-B, and HWRF), as well as \nthe statistical-dynamical models (SHIPS and LGEM), all suggest that \nIsaias could maintain major hurricane intensity up until its \nlandfall this evening. Therefore, the NHC official forecast depicts \nIsaias with 100-kt winds just offshore the western Florida \nPanhandle this evening. Weakening will occur after landfall, but \nsustained hurricane-force winds will likely occur near and along \nIsaias's track up to 100 miles inland from the coast into southern \nAlabama, and gusts to hurricane force could extend even farther \nnorth into central Alabama. Isaias is likely to lose its tropical \ncharacteristics by 36 hours when it is over northern Alabama.\n\nAircraft fixes indicate that Isaias has drifted a bit east of the \nprevious forecast track. NHC's track forecast leans on the eastern \nside of the guidance envelope, closest to the latest HCCA and GDMI \nguidance, and implies a potential landfall along the extreme \nwestern Florida Panhandle coast this evening. After moving inland, \nthe center of Isaias is expected to continue northward through \nAlabama, before turning northeastward over the Tennessee and Ohio \nValleys (as a post-tropical remnant low) on Sunday.\n\nNow that the eye has become visible in WSR-88D coastal radars, \nhourly Tropical Cyclone Updates will be issued beginning at 11 AM \nCDT (1600 UTC).\n\n \nKey Messages:\n \n1. A life-threatening storm surge is expected from the Mouth of the\nMississippi River to Suwannee, Florida. Residents under evacuation \norders should leave immediately and follow advice from local \nofficials. \n \n2. Extremely dangerous and damaging hurricane force-winds are \nexpected over portions of the Florida Panhandle, southern Alabama, \nand southern Mississippi where a Hurricane Warning is in effect. \nResidents in these areas should have a safe room to ride out the \nstorm and prepare for long-duration power outages.\n \n3. Damaging wind gusts are likely over a large portion of the \nsoutheastern United States from western and northern Georgia \nwestward over much of central and northern Alabama, southern middle \nTennessee, and Mississippi, especially in areas of higher terrain.\nResidents should secure loose outdoor items, avoid driving \nhigh-profile vehicles, prepare for power outages, and be aware of \nthe potential for falling trees.\n \n4. Isaias will bring areas of heavy rainfall to the central U.S. \nGulf coast and much of the Southeast through the weekend. \nConsiderable flash and urban flooding, and significant river \nflooding, are possible.\n\n5. The tornado potential will increase this afternoon and continue \nthrough tonight. The greatest risk will be east of the center, \nparticularly across the Florida Panhandle into southern Georgia. \nThis risk will continue spreading north-northeast across\nparts of the Southeast on Saturday.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  09/1500Z 27.7N  87.3W  105 KT 120 MPH\n 12H  10/0000Z 29.7N  86.8W  100 KT 115 MPH\n 24H  10/1200Z 32.1N  87.1W   55 KT  65 MPH...INLAND\n 36H  11/0000Z 34.2N  87.2W   35 KT  40 MPH...POST-TROP/INLAND\n 48H  11/1200Z 36.5N  85.0W   25 KT  30 MPH...POST-TROP/INLAND\n 60H  12/0000Z 39.1N  81.0W   20 KT  25 MPH...POST-TROP/INLAND\n 72H  12/1200Z...DISSIPATED\n \n"}