trowal

Short for trough of warm air aloft.

trowal (plural trowals)

1. (meteorology) The projection on the Earth's surface of the trough of warm air aloft formed during the occlusion process of the depression.
   • 2010, William R. Cotton, Storm and Cloud Dynamics, page 564:

     Mid-tropospheric frontogenesis occurred to the northwest of the negative EPV region as the trowal airstream became confluent with the cold air to the north of the cyclone.

• Occluded front on Wikipedia.Wikipedia