trowal Canadian meteorological term for the line of the upper front of an occlusion and for the region about it where the warm air, having been lifted off the surface, is still relatively low. It is a trough or valley of warm air that is still undergoing lifting, and is normally marked by clouds and precipitation.

trowal A Canadian meteorological term for the line of the upper front of an occlusion and the region about it where the warm air, having been lifted off the surface, is still relatively low. It is a trough or valley of warm air that is still undergoing lifting, and is normally marked by clouds and precipitation.