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| #1109155 (Received by flhurricane at: 4:59 AM 27.Sep.2022) TCDAT4 Hurricane Ian Discussion Number 17 NWS National Hurricane Center Miami FL AL092022 500 AM EDT Tue Sep 27 2022 Ian's satellite presentation continued to improve up until the center reached the coast of western Cuba around 0830 UTC. An Air Force Reserve reconnaissance aircraft that was in the storm until around 0400 UTC reported peak 700-mb flight-level winds of 101 kt, and a peak SFMR wind of 97 kt. During the final pass through the center, dropsonde data supported a minimum pressure of 960 mb. Given the continued improvement in satellite imagery, Dvorak data T-numbers from SAB and TAFB of T5.5 (102 kt), and objective estimates from UW/CIMSS of T5.4 (100 kt), the intensity was increased to 100 kt shortly after 0600 UTC. The latest objective Dvorak estimates have increased to around 110 kt, and that is the estimated landfall intensity and initial intensity for this advisory. NOAA and Air Force Reserve reconnaissance aircraft are scheduled to investigate the storm as it moves off the northern coast of Cuba this morning. Ian is expected to spend only spend a few hours over western Cuba, and little overall change in strength is likely during that time. The center should emerge over the southeastern Gulf of Mexico later this morning, where warm water and generally low vertical wind shear conditions are expected to allow for additional intensification, and the NHC forecast calls for Ian to reach category 4 strength. By 24 to 36 hours, increasing southwesterly vertical wind shear and drier mid-level air are likely to result in some gradual weakening. However, Ian is still expected to be a major hurricane when it reaches the Florida west coast. The official intensity forecast is near the latest simple and corrected multi-model consensus predictions. Ian has turned northward and is moving 355/10 kt. The hurricane should continue on a northward motion today around the western periphery of a subtropical ridge. After that time, a broad trough over the eastern United States is expected to cause a north-northeastward turn. There continues to be larger-than-normal spread in the track guidance by 36-48 hours, however the trend in the global models has been more southward and eastward over the last cycle or two. As a result, the NHC track has been adjusted to the southeast of the previous forecast and it lies just west of the TVCA multi-model consensus aid. Users are reminded to not focus on the exact track as some additional adjustments to the track are possible, and wind, storm surge, and rainfall hazards will extend far from the center. The updated forecast track has necessitated several changes to the warnings and watches across the Florida Keys and Florida peninsula, including an extension of the Hurricane Warning southward to Bonita Beach on the west coast. Key Messages: 1. Life-threatening storm surge, hurricane-force winds, flash floods and possible mudslides are expected in portions of western Cuba today. Devastating wind damage is expected where the core of Ian moves across western Cuba this morning. 2. There is a danger of life-threatening storm surge along much of the Florida west coast where a storm surge warning has been issued, with the highest risk from Fort Myers to the Tampa Bay region. Residents in these areas should listen to advice given by local officials. 3. Hurricane-force winds are expected in the hurricane warning area in west-central Florida beginning Wednesday morning with tropical storm conditions expected by late today. 4. Heavy rainfall will spread across western Cuba through Tuesday. This will likely produce instances of flash flooding and possible mudslides in areas of higher terrain over western Cuba. 5. Heavy rainfall will increase across the Florida Keys and South Florida Tuesday, spreading into central to northern Florida Wednesday and Thursday, and the Southeast by Friday and Saturday, likely causing flash, urban, and small stream flooding. Considerable flooding is expected across Central Florida into southern Georgia and coastal South Carolina, with significant, prolonged river flooding expected across central to northern Florida. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 22.3N 83.7W 110 KT 125 MPH 12H 27/1800Z 23.7N 83.7W 120 KT 140 MPH 24H 28/0600Z 25.4N 83.5W 115 KT 130 MPH 36H 28/1800Z 26.7N 83.1W 110 KT 125 MPH 48H 29/0600Z 27.6N 82.6W 105 KT 120 MPH 60H 29/1800Z 28.3N 82.2W 75 KT 85 MPH...INLAND 72H 30/0600Z 29.0N 82.0W 55 KT 65 MPH...INLAND 96H 01/0600Z 31.7N 82.2W 30 KT 35 MPH...INLAND 120H 02/0600Z 35.0N 82.0W 25 KT 30 MPH...INLAND $$ Forecaster Brown/Latto |
