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| #1109114 (Received by flhurricane at: 11:02 PM 26.Sep.2022) TCDAT4 Hurricane Ian Discussion Number 16 NWS National Hurricane Center Miami FL AL092022 1100 PM EDT Mon Sep 26 2022 Ian continues to become better organized on satellite images with intense deep convection in its Central Dense Overcast and numerous surrounding banding features. The overall cloud pattern is quite symmetric with well-defined upper-level outflow. Observations from both Air Force and NOAA Hurricane Hunter aircraft indicate that the central pressure is falling, and the intensity is increased to 90 kt based on a recently reported 700 mb flight-level wind of 101 kt from the Air Force plane. This is also in agreement with a subjective Dvorak satellite estimate from SAB. Aside from its relatively brief time passing over western Cuba, Ian will be moving over waters of very high oceanic heat content during the next couple of days. The various Rapid Intensification (RI) indices show a significant probability of RI and this is reflected in the short-term official intensity forecast. However, the SHIPS guidance, which is based on global model predictions, indicates that a significant increase in southwesterly shear and a substantially drying of low- to mid-level air will begin in 24-36 hours. The NHC forecast, like the previous one, shows strengthening to Category 4 intensity in a day or so, followed by 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 or above the latest simple and corrected multi-model consensus predictions. Ian continues its north-northwestward trek at about 340/11 kt. The hurricane is expected to move north-northwestward to northward over the southeastern Gulf of Mexico during the next day or so, along the western periphery of a subtropical ridge. After around 36 hours, the track forecast becomes more uncertain, since there is considerable divergence of the track models in the 2-3 day time frame. The guidance also shows considerable slowing of the forward speed, due to a weakening of the steering currents, when Ian approaches the west coast of Florida. This slower forward motion is likely to prolong the storm surge, wind, and rainfall impacts, especially along the west coast of Florida. The official track forecast is adjusted just slightly east of the previous NHC prediction based on the latest multi-model consensus aid, TVCN. Key Messages: 1. Life-threatening storm surge, hurricane-force winds, flash floods and possible mudslides are expected in portions of western Cuba beginning overnight and continuing into Tuesday. Devastating wind damage is possible where the core of Ian moves across western Cuba. Efforts to protect life and property should be rushed to completion. 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 Tuesday. 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 and northern Florida Wednesday and Thursday and the Southeast by Friday and Saturday, potentially causing flash, urban and small stream flooding. Considerable flooding, including significant, prolonged river flooding, is likely across Central Florida. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 21.3N 83.4W 90 KT 105 MPH 12H 27/1200Z 22.8N 83.7W 105 KT 120 MPH 24H 28/0000Z 24.5N 83.7W 120 KT 140 MPH 36H 28/1200Z 26.1N 83.5W 115 KT 130 MPH 48H 29/0000Z 27.2N 83.1W 105 KT 120 MPH 60H 29/1200Z 27.9N 82.7W 95 KT 110 MPH...INLAND 72H 30/0000Z 28.6N 82.4W 65 KT 75 MPH...INLAND 96H 01/0000Z 31.3N 82.2W 30 KT 35 MPH...INLAND 120H 02/0000Z 35.0N 81.5W 25 KT 30 MPH...INLAND $$ Forecaster Pasch |
