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. how quickly that air parcel … Read more 1.2.3. Updraft

1.2.3.1. Visual appearance and upward speed of the updraft

The visual appearance of the updraft can tell a lot about its strength and potential to produce a strong thunderstorm. As the updraft rises going through various phases of Cumulus and potentially Cumulonimbus , it cools and eventually looses buoyancy. In addition to the speed at which the updraft rises, the appearance of its edge … Read more 1.2.3.1. Visual appearance and upward speed of the updraft

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 altitude. Change in wind speed … Read more 1.2.3.2. Updraft depending on the wind

1.2.3.4. Equilibrium level (‚anvil level‘)

Now we have seen why some updrafts are vertical, while others are tilted and some even rotate. Now we take a look at what the top of the updraft looks like and why. We asked ourselves at the beginning of this section: Why does a Cumulonimbus capillatus get its distinctive fibrous top? Why does a … Read more 1.2.3.4. Equilibrium level (‚anvil level‘)

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 seconds, up to several minutes. … Read more 1.2.3.5. Overshooting top

1.2.3.6. Backsheared anvil – updraft strength vs. wind shear

Anvil vs. wind As the anvil is forming, it is under the influence of upper level winds. Typically as you go higher in the troposphere, winds increase. Under stable conditions with a high pressure, winds in the upper part of the troposphere can be very weak, below 10 km/h. However, under more unstable conditions when … Read more 1.2.3.6. Backsheared anvil – updraft strength vs. wind shear

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 and dissipate over a time … Read more 1.2.3.7. Mammatus clouds

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 produced the world record hailstone … Read more 1.2.3.8. The highest ever measured thunderstorms