Storm Cell over Aegina Greece Sept 2015 04

A storm cell is an

air mass In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to ...

that contains up and down drafts in convective loops and that moves and reacts as a single entity, functioning as the smallest unit of a storm-producing system. An organized grouping of thunder clouds will thus be considered as a series of storm cells with their up/downdrafts being independent or interfering one with the other.

Characteristics

A storm cell extend over an area the size of a few tens of square milles/kilometers and last 30 minutes or so. When the updraft and the environmental

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizon ...

is well coordinated, the size and the duration of the cell can be much greater leading to a

supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms ...

. Finally, storm cells can form on the outflow of previous cells leading to multicellular thunderstorms or mesoscale convective systems. Slow motion of these more intense storm cells or groups of cells can produce large precipitation accumulations and flash flood, or other dangerous phenomena like

hail Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...

and

tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, alt ...

es.

Life cycle

One can distinguish three stages in the evolution of a thunderstorm cell:. *formation: the upward current of the cell intensifies and allows the condensation of water vapor from the rising air parcel. This forms a cumulus congestus, then a

cumulonimbus Cumulonimbus (from Latin ''cumulus'', "heaped" and ''nimbus'', "rainstorm") is a dense, towering vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. ...

when ice crystals form at its apex which spreads horizontally in contact with the tropopause. *maturity: downdrafts are emerging. This stage is accompanied by characteristic phenomena such as

lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an average ...

and

thunder Thunder is the sound caused by lightning. Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning pr ...

, showers (sometimes

) and gust front. *dissipation: the cold pool descending from the cloud extends to the earth's surface and helps to block the feed by pushing the updraft downstream.

References

Storm Severe weather and convection {{climate-stub

Characteristics

Life cycle

See also

References