Rare vymeobrazny clouds appeared over St. Petersburg

On the morning of Sunday, August 1, vymeobrazny clouds were noticed in the sky over St. Petersburg. They are atypical for high latitudes. For their formation, a high thermodynamic instability of the atmosphere is necessary.

But this season their appearance is not accidental. The summer was very warm and hot in Sochi. In recent days, the weather is determined by a series of western cyclones. In the zone of contrasting atmospheric fronts, "light events" unfold with showers, thunderstorms, squalls and textured clouds.

Vymeobraznye clouds in the international classification (Mammatus) they are associated with the mother thunderstorm cell and most often occur immediately after a strong thunderstorm. The physics of their formation is based on a cell-like system of descending and ascending air movements against the background of a general descending flow in the rear part of a decaying thunderstorm cloud. The combination of multidirectional vertical movements leads to the formation of a characteristic shape at the base of the cloud cover. The total lifetime of such clouds varies from a few minutes to several hours.