A Supercell's Sunset Dawn
This cumulonimbus had a narrow updraft and forward-flank core area -- opaque enough to see the subtle refracted reds of sunset through both the updraft tower and precip core at right. But it was merging with a larger cell just to its N (right side, out of picture); and the combined storm would rapidly wind up into a tornado-producing supercell after dark. Just when I thought I was taking in the end of the day's sky show, Act Two was yet to begin! The supercell would put on a nice electrical display after dark.
5 WNW Gould OK (2 Apr 99), looking W.