Tropical Cyclone Discussion
963 WTNT44 KNHC 090858 TCDAT4 Hurricane Isaias Discussion Number 11 NWS National Hurricane Center Miami FL AL092026 400 AM CDT Fri Oct 09 2026 Isaias has intensified overnight. NOAA and Air Force Reserve Hurricane Hunter data showed that the maximum flight-level winds have increased up to 107 kt, with a better-defined eye and a shrinking eyewall. These changes are also present on satellite imagery, with a more symmetric presentation along with a warming eye/cooling eyewall. The available data suggest a current intensity of 95 kt for this advisory. Isaias will likely become a major hurricane soon with the improving satellite imagery, and it could continue to intensify for the next 12 hours or so while it moves over very warm and deep water. However, a large increase in shear is anticipated before landfall, which will probably cause some weakening to occur. This is a tenuous spot because it would only take about a 6h delay in the onset of the shear to bring a stronger hurricane than expected onshore. The new forecast explicitly is a bit higher than the last one, but our best forecast at this time is for a high-end category 2 intensity at landfall, which is about the same as before. Regardless of its exact wind speed at landfall, Isaias will be a dangerous hurricane with significant storm surge, damaging winds, and flooding rains. The wind field is also predicted to grow due to a trough interaction, and some of these impacts will extend well away from the center. After landfall, gusty winds are expected to reach well inland over portions of the southeastern United States. Isaias has turned towards the north-northeast (020/13 kt), and the hurricane is expected to turn northward and accelerate later today due to increasing flow between an upper trough near the northwestern Gulf Coast and a subtropical ridge extending across the western Atlantic. Landfall is expected to occur within the hurricane warning area Friday night or early Saturday. The new forecast is almost the same as before, very near the Google DeepMind guidance, which has been very accurate for Isaias. 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 today. 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 through the weekend. Considerable flash and urban flooding, along with significant river flooding, will be possible. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 26.4N 88.0W 95 KT 110 MPH 12H 09/1800Z 28.4N 87.3W 105 KT 120 MPH 24H 10/0600Z 31.0N 87.1W 65 KT 75 MPH...INLAND 36H 10/1800Z 33.5N 87.5W 35 KT 40 MPH...POST-TROP/INLAND 48H 11/0600Z 35.5N 86.7W 25 KT 30 MPH...POST-TROP/INLAND 60H 11/1800Z 38.2N 83.1W 15 KT 15 MPH...POST-TROP/INLAND 72H 12/0600Z...DISSIPATED