Fine line
From Glossary of Meteorology
fine line
A narrow radar echo indicating a boundary (such as a frontal boundary, gust front, or dryline) across which a density or moisture discontinuity exists.
The reflectivity is apparently explained by scattering from the refractive index gradients across the discontinuity and from insects and insect-eating birds that are concentrated along the line.
See clear-air echo.
See clear-air echo.
