Tropical Cyclone Discussion
823 WTNT44 KNHC 082100 TCDAT4 Hurricane Isaias Discussion Number 9 NWS National Hurricane Center Miami FL AL092026 400 PM CDT Thu Oct 08 2026 The eye of Isaias has become apparent on visible and infrared satellite imagery. Interestingly, this is the first eye noted on satellite pictures in the Atlantic basin during the 2026 Hurricane Season. The cloud tops have mostly warmed in the system, but the latest subjective Dvorak classification value from TAFB has increased to T4.5 or 77 kt. NOAA Hurricane Hunter aircraft observations do not indicate a drop in central pressure so far and the peak 700-mb flight-level winds have not increased. However, Tail Doppler Radar wind velocities from the aircraft measured just above the surface support increasing the intensity to 85 kt for this advisory. Satellite and aircraft center fixes indicate that the hurricane appears to have made its expected turn toward the northeast and the initial motion is now 050/10 kt. Isaias is expected to turn northward tomorrow and move between a mid-level ridge extending westward from the Bahamas to the Florida peninsula and a trough near the northwest Gulf Coast. On the forecast track, the center will move inland along the northern Gulf coast within the next 36 hours, and then pass over portions of the southeastern U.S. during the next few days. The official forecast is nudged slightly eastward and follows the latest corrected consensus model guidance. The intensity forecast remains somewhat problematic. The hurricane will be passing over Gulf waters of high oceanic heat content during the next day or so. In fact, the projected track of Isais shows it passing near a warm eddy overnight. However, the vertical wind shear, which is already significant, is expected to increase substantially during the next 36 hours. The current thinking is that the shear will not offset the conducive oceanic conditions until 12-24 hours, so further strengthening is anticipated overnight. The official intensity forecast is at the high end of the model guidance, but in consideration of the expected stronger wind shear in 24-36 hours, some decrease in intensity is indicated as Isaias approaches the coast. Regardless, Isaias is expected to remain a dangerous hurricane through landfall, and strong gusty winds are expected well inland after the center crosses the coast. Key Messages: 1. A life-threatening storm surge is expected from the Mouth of the Mississippi River to Suwannee, Florida. Residents in the warning area should follow advice given by local officials and evacuate immediately if told to do so. 2. Damaging hurricane force-winds are expected over portions of the Florida Panhandle, southern Alabama, and southern Mississippi where a Hurricane Warning is in effect. Residents in these areas should prepare for the possibility of long-duration power outages. 3. Damaging wind gusts are possible over much of central and northern Alabama, extreme eastern Mississippi, and portions of western and northern Georgia, especially in areas of higher terrain. Additional Tropical Storm and High Wind Watches and Warnings may be required for portions of that area later tonight. Residents should secure loose outdoor items, avoid driving high-profile vehicles, and prepare for power outages. 4. Isaias will bring areas of heavy rainfall to the central U.S. Gulf coast and much of the Southeast Friday into the weekend. Considerable flash and urban flooding, along with significant river flooding, will be possible. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 24.4N 89.3W 85 KT 100 MPH 12H 09/0600Z 25.7N 88.4W 95 KT 110 MPH 24H 09/1800Z 28.2N 87.4W 85 KT 100 MPH 36H 10/0600Z 31.0N 87.2W 65 KT 75 MPH...INLAND 48H 10/1800Z 33.2N 87.8W 30 KT 35 MPH...INLAND 60H 11/0600Z 35.0N 87.8W 25 KT 30 MPH...POST-TROP/INLAND 72H 11/1800Z 37.0N 85.0W 20 KT 25 MPH...POST-TROP/INLAND 96H 12/1800Z...DISSIPATED