Here are some reminders. Late blight of tomatoes doesn't infect tomatoes annually as does early blight. But it's more damaging to tomatoes than early blight. A few days of cool weather usually favors late blight. Cool nights and warm, damp days are ideal for its development.
Late blight is most common on Tennessee tomatoes in the late summer.
So listen to the weather forecasts. If conditions are going to favor the development of late blight, begin recommended control measures, even though you haven't detected it. If you don't and late blight develops, it can spread rapidly and cause major damage before you notice it. Here again, take preventative action. It's available through your local county Extension office.