What a day this has been in the tropics! In this morning’s post, hurricane watchers were worried that Investigation 99L might dissipate before becoming a tropical storm. But as of tonight, Invest 99L has become Tropical Depression #9 and the National Hurricane Center is now producing forecast information for its likely path later this week. Because it is still a very weak system, there is a lot of uncertainty in where the storm will go and how strong it will get (intensity is even harder to forecast than path), which means there is a very wide forecast cone showing where the storm could possibly go. If the storm follows the center of the cone, it is likely to cross the northern end of the Florida peninsula Thursday night into Friday morning as a tropical storm. But as the current map shows, it could make landfall south of Fort Myers FL or just east of Mobile AL, which leaves a lot of area to watch. Areas near the center of the storm, wherever it goes, are likely to see gusty winds and heavy rain (perhaps 5 inches or more in some locations). I think the heaviest rain will probably fall to the right of the path, so depending on where the center of the storm goes, southern Georgia could either get hit hard or almost missed by the rain.
Will the storm become Tropical Storm Hermine? Well, that depends. We were also surprised today by the development of Tropical Depression #8 off the East Coast. You can trace some of the energy in TD8 to Tropical Storm Fiona, but it has merged with other sources of energy to form this new low pressure area. It too is forecast to become a Tropical Storm. The next one on the list after Hermine would be Ian, but at this time it is hard to know which, if either, of these storms will reach tropical storm force first. Fortunately TD8 is only expected to affect North Carolina’s Outer Banks so most of the rest of the Southeast should not be affected by the storm except perhaps for some coastal waves and rip tides.
Meanwhile Hurricane Gaston is well out to sea and headed east, so it won’t affect us, but it has reached major hurricane status so it is quite a beast. And the next tropical wave just about to come off of Africa already has been forecast as having a 50 percent chance of development within five days, so that could be something to watch down the road.
Key points to keep in mind about TD9:
- The models are very unclear about what is going to happen with the storm, both in path and in intensity, so it is too early to make firm plans at this time. However, if you live anywhere in the forecast cone, you should have hurricane plans prepared just in case. And since the cone does change with each new forecast, if you are outside the cone but near it, you should be watching too.
- If you have vacation plans anywhere along the Gulf Coast for the Labor Day weekend, then you should pay careful attention to the forecasts from reliable sources like the National Hurricane Center. If the storm follows the path and timing as expected, then near it the beginning of the weekend could be wet and windy, but it might improve later in the weekend (depending totally on where you are and where the storm goes). Rip currents and high waves could be a problem.
- If you are hosting an outdoor event late in the week or are doing work outside that is dependent on weather conditions, you should also watch the path and timing of the event carefully. People in northern Florida and southern Georgia are particularly likely to see heavy rain ahead of the storm as it moves through the region, especially in areas to the right of the path. If the path shifts significantly in later forecasts, the expected weather could also change quite a bit.
- We are just reaching the peak of tropical storm season in the Atlantic, so don’t let your guard down once this storm passes. The next storm may be just a few days away.
For official hurricane information, see https://www.hurricanes.gov. Local NWS offices will also incorporate tropical storm information into their forecasts. For model runs and other info, I like https://www.spaghettimodels.com but there are many other sources. Beware of private forecasters who hype the most extreme models runs and stick to established forecasting firms like The Weather Channel, AccuWeather and Intellicast if you want reliable information.
