Fogtad

Fogtad is a term used in atmospheric science to describe micro-scale fog pockets that form near the ground in coastal and urban settings. The label combines “fog” with the imagery of a tadpole, referring to the common head-and-tail morphology reported in some observations. The concept is used mainly in niche studies of near-ground fog formation and in climate-phenomenon descriptions within regional meteorology.

Fogtad pockets develop when a shallow, moist layer near the surface cools radiatively after sunset, creating localized condensation. Turbulence and low wind shear can stretch patches into slender, elongated shapes that extend downstream from a denser fog core. These patches are typically a few meters to tens of meters thick and can drift with local airflow for minutes to an hour, sometimes dissipating quickly as air mixes.

Detection relies on ground-based cameras, lidar, and drone imagery. Meteorological stations may indicate rapid changes in visibility and dewpoint near the surface. Fogtad is noted for its transient nature and variable contrast against the surrounding air, which can complicate standard fog forecasts.

Reported mainly in coastal temperate regions and narrow river valleys, fogtad is not yet a globally standardized category in meteorology. It has appeared in climate journals as a descriptive term in microclimate studies and in nature writing to evoke atmospheric texture. See also: fog, mist, boundary layer, radiative cooling, urban climate.