As of 5 am this morning, Ian became a hurricane as it moved over very warm water in an area with no wind shear overhead. Over the course of the day, it has been steadily gaining strength as it continued to move NW and now NNW towards the western tip of Cuba. The outer bands of rainfall are hitting the southern tip of Florida now and will move towards the north as the storm progresses. It should pass over there in the next few hours and then enter the eastern Gulf of Mexico, which is also very warm. It is expected to continue to strengthen until it gets near Tampa, then is expected to slow down to just a few miles per hour and spin there until it starts interacting with a mid-latitude trough that will pull it towards the northeast. By then, cooler temperatures, dry air pulled in from the continent, and strong wind shear will cause it to start to weaken as it moves towards the northeast. But it will still be a large and powerful storm, so impacts are expected to be widespread and severe.
Yesterday you might recall that the models were trending westward over time. Today, they have been drifting back to the east, so more individual model runs are showing Ian crossing the Florida peninsula, entering the Atlantic Ocean, and then swinging left back into Georgia or South Carolina. The 11 pm forecast cone shows that eastward shift. But there are plenty of model tracks showing a different pattern, so it is too early to say for sure what the final track is likely to be. That means a wider area of preparation for the Southeast as a whole. If the storm ends up in the Gulf just west of Tampa, the storm surge and wind damage there will be severe, and evacuations from low-lying areas are underway now. If the storm stalls south of Tampa or crosses onto the peninsula, the surge will be lower, although the wind will remain. Surge of up to 3 feet is already being predicted for the East Coast, including a long stretch of Florida as well as the South Georgia coastline where onshore winds will drive water inland. If the storm track moves back to the west, this will become less likely, but it is still too early to be sure.
Most of Florida and Georgia and parts of adjoining states will experience periods of heavy rain, strong wind gusts, and isolated tornadoes. Fortunately, as the storm weakens, the winds will decrease. Rainfall of 2-4 inches is expected across most of GA and SC, with higher amounts near the coast. Florida will get much more, and flooding is likely there because of the high rain amounts.
The slower forward movement of the storm once it gets close to Tampa means that areas farther north will also see impacts begin a bit later than previously forecast. That means tropical storm force winds most likely won’t affect southern GA and AL until mid-day on Thursday, and the center of the storm itself won’t enter Georgia (on its current predicted track) until Friday afternoon as a much weaker storm and it may not be out of the state until Saturday afternoon. Areas west of the storm’s path will see less rain and wind, but could still feel impacts while the storm is headed their way.
Because of the continuing uncertainties with the timing, strength, and track of the storm, I expect to see further changes to the track, although it’s interesting to see that the forecast cone has not shifted that much over time, just inching to the west and then the east. But the width of the cone after Tampa indicates how unclear the track is after that. For now, areas that are north of Tampa should continue their preparations for the most severe local weather expected, just in case. I’ve seen plenty of pictures on Twitter of farmers harvesting cotton and pecans (where they are ready) ahead of the storm today, and I expect more of that tomorrow and Tuesday as well.
As the storm churns north, continue to monitor the National Hurricane Center for hurricane forecasts and your local NWS office for local weather conditions. If your local emergency manager issues evacuation orders, get out as soon as you can to beat the crowd of those who take longer to pack. I expect to do another update tomorrow night after the 11 pm map is issued.