isotach
[ˌaɪsoʊˈtæk]
Definitions
1. noun
A sharp, narrow band of cloud, often associated with a thunderstorm, in which the cloud layer is uniform in density and the air is uniform in temperature and humidity, usually visible as a dark band or a narrow, wispy cloud layer.
“The forecaster predicted that the storm system would produce an isotach of heavy rain over the region.”