A rare phenomenon over the city of Kavala in Northern Greece: A storm with a shelf cloud. A low-hanging, well-defined, wedge-shaped formation that occurs along the leading edge of a gust front in a thunderstorm. Shelf clouds most often form just ahead of intense lines of thunderstorms.
Shelf clouds are considered as one of the most awesome and most alarming phenomena.
The storm broke out after 06:30 Tuesday afternoon, July 17, 2018.
Rain-chilled air descends in a thunderstorm’s downdraft, then spreads laterally when reaching Earth’s surface. Warmer, more moist air is lifted at the leading edge, or gust front, of this rain-cooled air. When this warm, moist air condenses, one sees the shelf cloud.
