AstroScan's Threatening Skies Screen Saver - Version 1.0 A Thunderstorm approaches - With it comes lightning, thunder, heavy rains, and the possibility of a twister - See the beauty and power of nature in the screen saver. You'll see lightning strikes, a storm as it moves off-shore, a funnel cloud, and the ominous looking roll clouds of an approaching storm. Included are the sounds of rain and storm.