summer potato storage

I have hot dry summers where I live, so grew the potatoes early to beat the summer heat, so far so good.  

But, now, I have a large potato yield.

The water table is too high to dig in ground storage.

I only need to store them until November or so, I hope to put in a second fall crop of potatoes to eat over the winter.  The varieties are yukon gold and red norland

A secondary question is how to make sure the ones I want to use as seed potatoes in August will be ready to want to sprout then

In the tropics, they use diffused light storage for potatoes.  You basically want to keep the insects and rodents away from them, protect them from high temperatures, and keep them in enough light to reduce sprouting when dormancy ends.  Some shelving wrapped in shade cloth, located in a shady spot would be a minimal solution.  Or, if you have a cool room in your house with a window, you could keep them there.  You should have no problems with your seed potatoes being ready to plant.  Potatoes stored in warm temperatures will have only two or three months of dormancy.