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?
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."
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.
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.
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 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.
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.
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.
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.