Regardless of where you are in this journey, chances are that your lawn will need some amount of repair come fall. In Charlotte, the sweet spot for overseeding tall fescue is mid-September to mid‑October, when soil temps approach 70deg:

http://www.greencastonline.com/tools/soil-temperature

Don’t be fooled by a quick cool temp period followed by an extended hot period, it’s better to wait. I try to time the exact day of action when the forecast has some consistent light rain for the next few days. Avoid any downpours if possible, we don’t want all our time and money washing into the sewer.

Quick game plan

  1. Mow low (about 2.5–3.0") and bag the clippings.
  2. Dethatch only if you truly have thatch (> ½"). Otherwise, just use a rake to scuff up the surface of any bare dirt spots.
  3. Core aerate (at least two passes).
  4. Amend soil based on a recent soil test (lime/compost as needed).
  5. Spread seed at the right rate with good seed‑to‑soil contact.
  6. Spread starter fertilizer.
  7. Water like a metronome. First light and frequent, then deeper and fewer.

Use a quality tall fescue blend suited to Zone 8a. Diversity in cultivars = better odds.