Cold front known as veering, and in the southern hemisphere a shift from northwest to southwest (anticlockwise, backing). Normally, cold fronts can be marked by these characteristics: <nowiki>*provided there is sufficient moisture.</nowiki> If the cold front is highly unstable, cumulonimbus clouds producing thunderstorms commonly form along the front. Anvil cirrus clouds may spread a considerable distance downwind from the thunderstorms. The other cloud types associated with a cold front depend on atmospheric conditions such as air mass stability and wind shear. As the front approaches, middle-étage gives way to altostratus and low-level stratocumulus with intermittent light precipitation if the warm airmass being
Wall cloud within the leading edge (typically of a quasi-linear convective system (QLCS) or squall line) on rare occasion. The wall cloud feature was first identified by Ted Fujita and as associated with tornadoes in tornadic storms following a detailed site investigation of the 1957 Fargo tornado. In the special case of a supercell thunderstorm, but also occasionally with intense multicellular thunderstorms such as the aforementioned QLCS, the wall cloud will often be seen to be rotating. A rotating wall cloud is the area of the thunderstorm that is most likely to produce tornadoes, and the vast majority of intense tornadoes. Tornadogenesis