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| #1058962 (Received by flhurricane at: 10:41 PM 27.Aug.2021) TCDAT4 Hurricane Ida Discussion Number 7 NWS National Hurricane Center Miami FL AL092021 1100 PM EDT Fri Aug 27 2021 Ida made landfall in the Cuban province of Pinar Del Rio around 2320 UTC with maximum sustained winds estimated to be around 70 kt. Radar data from Cuba indicate that the inner core of Ida has remained intact after its passage over western Cuba with a well-defined eye and relatively symmetric eyewall evident. In addition, satellite images show deep convection increasing in both intensity and coverage, a sign that Ida is strengthening. The Air Force Hurricane Hunters are currently investigating Ida and so far have found maximum 700 mb flight-level winds of 75 kt. Based on that data, the initial intensity is held at 70 kt. The hurricane is moving northwestward at about 13 kt. A subtropical ridge centered off the southeast U.S. coast is expected to shift westward through the weekend. This feature should continue to provide a steering flow that will take Ida steadily northwestward across the Gulf of Mexico during the next couple of days. The models remain in very good agreement and show Ida making landfall in Louisiana late Sunday or early Monday morning. After the storm moves inland, a decrease in forward speed and a turn to the north and then the northeast is predicted as Ida moves in the flow on the northwest and north sides of the ridge. Since the models are tightly clustered and because the steering flow is well pronounced, there is high confidence in the track forecast. The new NHC track forecast is very similar to the previous one and near the various consensus aids, which are often the most accurate models. Users are again reminded to not focus on the exact details of the track forecast as storm surge, wind, and rainfall impacts will extend far from the center. Ida is expected to remain in conducive conditions for intensification until it reaches the central Gulf coast. The global models show a very favorable upper-level wind pattern over the storm and abundant environmental moisture. These conducive atmospheric conditions combined with very warm Gulf of Mexico waters should allow Ida to rapidly intensify this weekend. In fact, it seems likely that Ida will pass over a warm eddy over the central Gulf of Mexico, where the ocean heat content is very high. All of the models show significant strengthening, but there is a fair amount of spread on how strong the hurricane will get. The NHC intensity forecast remains near the high end of the model guidance, and shows Ida becoming an extremely dangerous category 4 hurricane prior to reaching the coast. After landfall, rapid weakening is expected due to land interaction, drier air, and an increase in shear. As Ida continues to intensify over the Gulf of Mexico, an expansion of its wind field is predicted. The NHC wind radii forecast is largely based on the radii consensus, and winds of at least tropical storm force are likely to reach the coast Sunday morning. Therefore, all preparations to protect life and property for this dangerous event need to be made on Saturday. Key Messages: 1. Life-threatening storm surge and hurricane conditions are expected to continue for the next few hours in portions of western Cuba, including the Isle of Youth, where a Hurricane Warning is in effect. Life-threatening heavy rains, flash flooding and mudslides are expected across Jamaica, the Cayman Islands, and western Cuba, including the Isle of Youth. 2. There is a danger of life-threatening storm surge inundation Sunday along the coasts of Louisiana and Mississippi within the Storm Surge Warning area. Extremely life-threatening inundation of 10 to 15 feet above ground level is possible within the area from Morgan City, Louisiana, to the Mouth of the Mississippi River. Interests throughout the warning area should follow any advice given by local officials. 3. Ida is expected to be an extremely dangerous major hurricane when it reaches the coast of Louisiana. Hurricane-force winds are expected Sunday in portions of the Hurricane Warning area along the Louisiana coast, including metropolitan New Orleans, with potentially catastrophic wind damage possible where the core of Ida moves onshore. Actions to protect life and property should be rushed to completion in the warning area. 4. Ida is likely to produce heavy rainfall later Sunday into Monday across the central Gulf Coast from southeast Louisiana to coastal Mississippi and Alabama, resulting in considerable flash, urban, small stream, and riverine flooding impacts. As Ida moves inland, flooding impacts are possible across portions of the Lower Mississippi and Tennessee Valleys. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 23.0N 84.0W 70 KT 80 MPH 12H 28/1200Z 24.4N 85.6W 85 KT 100 MPH 24H 29/0000Z 26.1N 87.7W 105 KT 120 MPH 36H 29/1200Z 27.8N 89.6W 120 KT 140 MPH 48H 30/0000Z 29.2N 90.8W 110 KT 125 MPH...INLAND 60H 30/1200Z 30.7N 91.0W 60 KT 70 MPH...INLAND 72H 31/0000Z 32.3N 90.6W 35 KT 40 MPH...INLAND 96H 01/0000Z 34.9N 88.2W 25 KT 30 MPH...INLAND 120H 02/0000Z 36.8N 83.9W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi |
