Overcast
Cloud cover that blankets the whole sky and shuts out the sun.
What it means
Without sunshine the ground stops heating and fresh thermals stop forming. Overcast describes the covered sky; cumulus spreading out into a layer is one way it develops, not another name for it.
Example in context
By midday it had gone overcast and the thermals died almost at once.
Sources and review
- NWS Glossary: Overcast (opens in a new tab)
- Tom Bradbury: Cumulus spread out (Sailplane & Gliding) (opens in a new tab)
- Jakub Vrána — Paraglidingový slang: o počasí (opens in a new tab)
Reviewed: