Overfog

Overfog refers to a meteorological phenomenon characterized by a dense layer of fog that persists for an extended period, often for multiple days. This can occur in various geographical locations but is particularly common in coastal areas, valleys, and regions with high humidity. The formation of overfog is typically a result of a combination of factors including stable atmospheric conditions, a source of moisture, and a cooling mechanism that causes the air to reach its saturation point.

Unlike transient fog, which dissipates relatively quickly with changes in temperature or wind, overfog is sustained by a continuous supply of moisture and a lack of atmospheric mixing. This can be exacerbated by temperature inversions, where a layer of warm air traps cooler, moist air near the surface, preventing vertical dispersion of fog. The prolonged presence of overfog can significantly impact visibility, leading to disruptions in transportation, including air, sea, and road travel. It can also affect local ecosystems, influencing light levels and temperature for plant and animal life. The duration of overfog is dependent on the persistence of the meteorological conditions that create and maintain it.