Encara no tenim significats per a "heavy thundercloud".
1Outside a heavy thundercloud gathered and darkened the room.
2Rilla scanned the sky also; she did not like its appearance; a heavy thundercloud was appearing in the northwest.
3Warm air starts rising up into cooler climes and condenses to build dark, heavy thunderclouds.
4It seemed as if a gloomy multitude of heavy thunderclouds had gathered over the still, blue arm of the sea.
5It was a dark evening for the time of year; heavy thunderclouds were hanging low in the sky and obscuring the light.
6It was then five o'clock, and the approach of darkness was accelerated by the heavy thunderclouds which were gathering over the northern mountains.
Aquesta col·locació està formada per: