000 WTNT44 KNHC 271500 TCDAT4 Hurricane Ian Discussion Number 18 NWS National Hurricane Center Miami FL AL092022 1100 AM EDT Tue Sep 27 2022 The well-defined eye of Ian emerged off the coast of western Cuba about an hour ago. Earlier reports from the NOAA Hurricane Hunter aircraft indicate that Ian strengthened up through landfall, with an estimated pressure of 947 mb over western Cuba. While the hurricane has filled somewhat due to the passage over Cuba, Air Force Reserve and NOAA Hurricane Hunter data show that it has grown in size. The initial wind speed is set to 100 kt. Ian is moving northward, or 005/9 kt. Dropsonde data from the NOAA G-IV aircraft indicate a potent upper-level trough is over the western Gulf of Mexico. The strength of this trough, the associated southwesterly flow, and the vertical depth of Ian appear to be the keys to the forecast. There has been a notable trend toward the hurricane remaining more intact up through landfall, meaning Ian is likely to turn to the northeast and not move as slowly as previously anticipated. However, it should be emphasized that this track remains very uncertain, with a typical spread in the steering features leading to big speed and track differences down the line, not to mention the oblique angle of approach to Florida. The latest forecast is adjusted to the southeast for this advisory, showing landfall 6-12 hours faster than before, and we will have to see if the southern trend continues in the afternoon guidance. The rest of the forecast after landfall has been adjusted to the northeast as well, though it is still slower than the consensus guidance at longer range. The hurricane should remain in a favorable environment for restrengthening over the next day or so while it moves over the warm waters of the southeastern Gulf of Mexico and in light-shear conditions. While the shear should increase by tomorrow, it isn't expected to be enough to significantly weaken the hurricane before landfall. Model guidance is in fairly good agreement on this scenario, and the NHC intensity forecast continues to call for an extremely dangerous hurricane landfall for southwestern Florida. The new forecast necessitates a Hurricane Watch for portions of extreme southwestern Florida, and a Tropical Storm Watch for the rest of southeastern Florida that wasn't previously under a watch. Users are reminded to not focus on the exact track as some additional adjustments to the track are possible. Significant wind, storm surge, and rainfall hazards will extend far from the center. Key Messages: 1. Life-threatening storm surge, hurricane-force winds, flash floods and possible mudslides are expected to continue in portions of western Cuba today. Devastating wind damage is expected near the core of Ian. 2. Life-threatening storm surge looks increasingly likely along much of the Florida west coast where a storm surge warning is in effect, with the highest risk from Fort Myers to the Tampa Bay region. Residents in these areas should listen to advice given by local officials and follow evacuation orders if made for your area. 3. Hurricane-force winds are expected in the hurricane warning area in southwest and west-central Florida beginning Wednesday morning with tropical storm conditions expected by this evening. Residents should rush all preparations to completion today. 4. Heavy rainfall will increase across the Florida Keys and south Florida today, spreading into central and northern Florida tonight and Wednesday, into the Southeast U.S. by Thursday and Friday, likely causing flash, urban, and small stream flooding. Considerable flooding is expected across central Florida into southern Georgia and coastal South Carolina, with widespread, prolonged moderate to major river flooding expected across central Florida. FORECAST POSITIONS AND MAX WINDS INIT 27/1500Z 23.0N 83.5W 100 KT 115 MPH 12H 28/0000Z 24.4N 83.3W 115 KT 130 MPH 24H 28/1200Z 26.0N 83.0W 115 KT 130 MPH 36H 29/0000Z 27.1N 82.5W 110 KT 125 MPH 48H 29/1200Z 27.8N 82.1W 75 KT 85 MPH...INLAND 60H 30/0000Z 28.5N 81.7W 60 KT 70 MPH...INLAND 72H 30/1200Z 29.5N 81.5W 50 KT 60 MPH...INLAND 96H 01/1200Z 33.0N 81.8W 35 KT 40 MPH...INLAND 120H 02/1200Z 35.0N 81.5W 25 KT 30 MPH...POST-TROP/EXTRATROP $$ Forecaster Blake