Undulatus

[byslantedlight.livejournal.com]

Woke up to a grey morning, and thought it was going to rain all day, but then I caught sight of something more promising to the west, and next thing I know - undulatus! *g*

Apparently they're formed when air above and below the cloud layer is moving at different speeds or in different diretions, and according to my Cloud Collector's Handbook, Their presence is a reminder, to anyone who might forget, that the atmosphere around is just as much an ocean as is the sea below.

According to other websites, they may indicate precipitation later in the day, so let's see... *g*