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Types of Thunderstorms
single cell, multicell clusters, multicell lines and supercells
The array of thunderstorms within the
spectrum reflects our current scientific
understanding. Thus, while the spectrum is
very useful, it is neither perfect nor a
final solution. Nevertheless, arrangement
of storms within the spectrum is dependent
on updraft strength, here represented by
different colors; relative frequencies of
these updraft strength categories, as
indicated by differing lengths on the upper
bar graph; and relative threats of the updraft
categories, here represented by the lengths on
the bottom bar graph.
[Image: thunderstorm spectrum (33K)]
||Thus, while a "strong"
updraft is less common than a "weak" updraft,
the relative threat to life and property is
greater with the "strong" updraft storm. Similarly,
"intense" updraft storms are quite rare but
inflict a disproportionate amount of damage
and personal injury.
The breakdown into single cell, multicell,
and supercell covers the major storm types
within the spectrum. One "cell" denotes one
updraft/downdraft couplet. Thus, there are
several updrafts and downdrafts in close
proximity with a multicell storm. Multicell
storms can be broken down further into the
categories of multicell line and
The "intense" updraft storm is almost
invariably the supercell, a storm capable
of producing the most devastating weather,
including violent tornadoes.
[Image: four basic thunderstorm types (27K)]
||With the two multicell storm categories,
we have defined four basic storm types from
the thunderstorm spectrum. The supercell
is always severe, whereas the others can be
non-severe or severe. We stress that a "severe"
storm is a somewhat arbitrary National
Weather Service definition of a storm with
one or more of the following elements: 3/4 inch
or larger diameter hail, 50 KT downbursts,
Before reviewing these storms, it is
important to emphasize that real thunderstorms
do not always fit neatly into the categories
we have just described. Research has suggested
that the most basic distinction among storm
types is between supercells and everything
else, the so-called "ordinary" cells.
Non-supercell storms consist of one or more
ordinary cells, and we have described three
basic ways in which ordinary cells commonly
occur: as isolated cells, as clusters of cells,
and in lines of cells. Even though real storms
can have physical traits that cross the
boundaries of these categories, this
classification scheme still has considerable
value. This is because the intensity
and type of weather events produced by
a storm tends to be dependent on which
category it fits most closely. We should
also point out that a given storm may change
its type one or more times during its existence.
Last Update: 7/23/97
Single Cell Storms
Typically last 20-30 minutes. Pulse storms can produce severe weather
elements such as downbursts, hail, some heavy rainfall
and occasionally weak tornadoes.
Multicell Cluster Storms
A group of cells moving as a single unit, with each cell in a different
stage of the thunderstorm life cycle. Multicell storms can produce
moderate size hail, flash floods and weak tornadoes.
Multicell Line Storms
Multicell line storms consist of a line of storms with a continuous,
well developed gust front at the leading edge of the line.
Also known as squall lines, these storms can produce small to moderate
size hail, occasional flash floods and weak tornadoes.
Defined as a thunderstorm with a rotating updraft, these storms can
produce strong downbursts, large hail, occasional flash floods and weak to
Dangers of T-storms
Single Cell Storms