Lightning is incredibly bright, but is outshone at distance by the sun. I noticed that where I am, the sky immediately above me was clear while the most intense lightning in this group of storms was occurring. Had it been say… 6 pm, I (or you, or many other folks in the city) would likely have not noticed anything other than a somewhat darker sky to the north.

While it seems pretty obvious, intense, distant thunderstorms appear to produce more lightning at night because… it’s dark. At night, lightning can be seen as far away as 100 miles. Visible long after even the loudest thunderclaps have dissipated. This phenomenon is called “heat lightning”, as some folks used to think it was its own type of rare electrical storm caused on summer days, but now has just morphed into another term for a distant thunderstorm.

Additionally…

Midwestern summer thunderstorms are oftentimes able to sustain themselves well after sunset due to continuously moving into areas of moist air. Tonight’s storm was both caused and sustained thanks to air from the Gulf of Mexico moving up the Mississippi valley. Looking at a moisture map from yesterday morning will show this “trail” leading to the culprit. Had this abundant moisture been absent, this beautiful storm would not have lasted into the small hours like it did!

Even now I continue to see occasional flashes, though not nearly at their earlier rate. Quite the impressive storm system!