Tropical Storm Grace formed on Saturday morning from what was Invest 95L, then PTC7, then TD7. If that's confusing, don't worry about it, just call it Grace now. Grace is rapidly approaching the Leeward Islands, and strengthening. Grace also makes 2021 join a very elite and infamous list of hyper-active hurricane seasons that had their seventh named storm form by this date: 2020, 2017, 2005, and 1995 (since the reliable satellite era began about 55 years ago).
Grace is going to follow a track similar to Fred's over the next few days. But the details matter. Fred passed directly over Hispaniola and that was its undoing. Grace could just barely miss it and have a totally different outcome. So, the intensity forecast beyond there is quite challenging, but for now, NHC is keeping it as a tropical storm. [refresher on the "cone of uncertainty"]
Clearly, interests in the Greater Antilles and Florida should be watching this very closely. Heavy rain is a concern along its path, but if it should strengthen more than the current forecast, the other hurricane-related hazards start to enter in.
The timing of possible impacts in Florida have been consistent for the past few days: Wednesday-Thursday. As far as intensity goes by that time, it's too early to say, but there is model guidance that suggests a hurricane is not out of the question. For some historical context, the last two hurricanes to make landfall in south Florida were Irma (2017) and Wilma (2005), so it's not as common as many people think. Also, it if follows the northern/Florida route, it would likely end up in the Gulf of Mexico.
The Saturday afternoon of deterministic model guidance is shown below on the left, and the GFS ensemble (color-coded by pressure) is shown on the right. While that map of ensemble tracks might look useless, it actually isn't. It illustrates two basic yet realistic scenarios: Grace weakens by the time it reaches Hispaniola and the weaker storm travels west across the Caribbean, OR, Grace strengthens by the time it reaches Hispaniola and the stronger storm travels west-northwest just skimming north of the Greater Antilles.
Fred has dissipated to an open wave centered over western Cuba as of Saturday morning, BUT, we have probably not heard the last of that name this year. The center failed to redevelop after leaving Hispaniola, then the trek over Cuba was just too much for it. It's about to enter the eastern Gulf of Mexico, where conditions are favorable for redevelopment over the next couple of days.
In the meantime, it is a large sloppy system with strong thunderstorms and heavy rain reaching from central Cuba to central Florida. Although the heaviest rain should remain west/offshore of the Florida peninsula, there will be periods of heavy rain -- the highest totals are expected in the panhandle.
Assuming it does regain tropical storm status, which many models support, tropical storm force winds could reach the north-central Gulf coast by Monday morning. As of now, there isn't an indication that it will reach hurricane strength.
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