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The many different varieties of thunderstorms

Single_Cell
Single-cell thunderstorms contain only one updraft and are typically short-lived.
Multi_Cell
Multi-cell thunderstorms possess multiple updrafts. They can occasionally produce hail and damaging winds.
Squall_Line
Squall lines are multi-cell thunderstorms that generally have brighter colors along a solid, continuous line. They can produce large hail and damaging winds.
Supercell
Supercells are strong thunderstorms that possess a large, rotating updraft. Large hail and even tornadoes are possible where supercells form.

ROCKFORD (WREX) — Thunderstorms are by far one of nature's most fascinating types of weather. But did you know there are many different kinds of thunderstorms?

Single-cell thunderstorms:

This type of convection is often referred to as "popcorn" thunderstorms. Single-cell thunderstorms are small, brief, and usually weaker. The typical lifespan of a single-cell thunderstorm is less than an hour, as they're usually quick to "rain their selves out."

A mature cumulonimbus. Image courtesy of the NWS.

The quickly developing showers and thunderstorms are driven by heating, especially during the summer afternoons. They can produce briefly heavy rain and lightning, but severe weather isn't typically observed.

Multi-cell thunderstorms:

Thunderstorms that are able to produce multiple updrafts are considered multi-cellular thunderstorms. These usually develop along an outflow boundary or gust front of rain-cooled air. An outflow boundary acts like a miniature cold front, providing additional lift for more thunderstorm development.

Individual cells may last only an hour or so, but the system as a whole can last for many hours. Multi-cell thunderstorms are capable of producing hail, strong winds, brief tornadoes, and even flooding.

Squall lines:

A line of storms accompanied by squally winds and heavy rain are called squall lines. They typically move quickly through any given area and are less prone to produce tornadoes than supercells. They can be hundreds of miles long and the worst of the weather is typically only 10 to 20 miles wide.

A large line of strong thunderstorms moving through the Stateline. This system produced large hail in spots and damaging winds all along the line. The backward C-shape is referred to as a "bow echo." Image courtesy of the NWS-Chicago.

Derechos:

A long-lived wind storm associated with a band of rapidly moving thunderstorms is referred to as a derecho (pronounced similar to "deh-REY-cho" in English). A derecho can produce damage that visually looks similar to tornadoes, however damage is typically directed in one direction along a relatively straight swath.

A powerful derecho moved through the Rockford region in July of 2003. Widespread wind damage was caused, which is typical of long-lived derecho systems. Image courtesy of the NWS-Chicago.

The term "straight-line wind damage" is sometimes used to describe damage done by a derecho. This type of thunderstorm complex has a very specific set of criterion to be met: a wind damage swatch of more than 240 miles and wind gusts of at least 58 miles per hour along most of its length.

Supercells:

Storms that are most likely to produce tornadoes are known as supercells. A supercell is a long-lived and highly organized storm feeding off of a tilted and rotating updraft. The updraft, which can be up to 10 miles wide and up to 50,000-feet tall, can be present as early as 20 to 60 minutes before a tornado forms. This rotation is called a "mesocyclone" and is able to be detected on Doppler radar.

A simplified depiction of a supercell. Notice how small the tornado is in the bottom-center of the picture in relation to the storm itself. Image courtesy of the NWS.

Not all supercells produce tornadoes, but most large and violent tornadoes are spawned from supercells. The tornado is only a very small extension of this large rotation.

Justin Ballard

Justin Ballard joined 13 WREX as the weekday morning meteorologist. He’s a proud graduate of UNC-Charlotte and happy to call Rockford home.

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