Whenever I see this kind of sky, I'm reminded of paintings of Jesus that I used to see as a kid, where he's kneeling at a rock, praying, and looking up to the heavens. In the background, rays of light are breaking through dark, forbidding clouds. For that reason, whenever I see a sky like this, the phrase 'biblical light' pops into my mind.
The real reason for this kind of sky isn't very sacred, though. In the Pacific Northwest we usually see this kind of light when there is quite a bit of smoke or smog in the air.
For an excellent discussion of cloud heights and types, along with tips on short-term weather forecasting based on your own observations of the sky, click here.
For a great and simple explanation of the mechanics of storm fronts, visit this page.
Ash Creek Images
Photographs of the West by Doug Gorsline
Beams of Sunlight Break Through Heavy, Dark Cumulus Clouds.
