Before I answer that, just a quick look at the storm and what's around it to get an understanding of it all. First up, the current surface map is just to the left. You can see the storm just off the coast of Florida, and a few fronts above it with the central Low (triple point) in Ohio.
Now, those fronts will play a very important role in the positioning of Andrea. If you didn't know what all those symbols mean:
SO, next up is the winds. The main thing to keep an eye out for here is that cold front extending from Ohio into Mississippi. Why? Because ahead of a cold front, winds always move along it towards the low, as you can see below:
SO, with all of that said, here's the skinny on how it will most likely be moving in a simple gif below. Just keep in mind what I said above, and that the precipitation from Andrea will combine itself with the precip from those fronts, and you'll get a good idea of why there will be so much precip over a large area.