Category: 1. Introduction to convective weather

1.2.3. Updraft

Updraft The updraft of the thunderstorm is the convectivelly rising moist warm air. It is invisible to the eye below the condensation level and becomes visible as the ‘cauliflower’ cloud above the condensation level. The updraft varies a lot between different thunderstorms. Its strength, the air velocity within it (i.e....

1.2.3.2. Updraft depending on the wind

As you watch cumulus and cumulonimbus clouds forming on different days, you will notice on some days the updrafts grow vertically upwards, while on other days they are tilted. The tilt of an updraft depends on the strength, the upward speed of the updraft and how the wind changes with...

1.2.3.3. Pileus cloud caps

Often, a white wispy cloud cap forms above rapidly rising updraft – a pileus cloud. It forms as moist, but stable air above a rapidly rising updraft is pushed upward, causing the water to condense. It is a short-lived cloud, which either fades or is overtaken by the rising updraft,...

1.2.3.5. Overshooting top

Overshooting tops develop on thunderstorms that have particularly strong updrafts. Overshooting tops typically develop on Cumulonimbus capillatus incus clouds. The updraft punches through the equilibrium level (and thus the anvil), rising higher due to its momentum, despite not being buoyant anymore. An overshooting top is usually short-lived, several tens of...

1.2.3.7. Mammatus clouds

Mammatus clouds form on the underside of a thunderstorm’s anvil. The name mammatus comes from the Latin word mamma, meaning “udder” or “breast”. They appear as pouch-like structures protruding from underneath the anvil. Mammatus clouds are gentle downdrafts – sinking cool air – descending from the anvil, that form, evolve...

1.2.3.8. The highest ever measured thunderstorms

The strongest updrafts reach the tropopause and produce overshooting tops. The highest thunderstorms in the world have been recorded in the tropics, where the tropopause is the highest (15-18 km). Thunderstorms reaching 20-22 km high have been recorded there. The July 23, 2010 Vivian, South Dakota severe supercell thunderstorm, which...