SINGLE CELL STORM: Single cell thunderstorms usually last
between 20-30 minutes. A true single cell storm is actually quite
rare because often the gust front of one cell triggers the growth
cell storms are not usually severe. However, it is possible for
a single cell storm to produce a brief severe weather event. When
this happens, it is called a pulse severe storm. Their updrafts
and downdrafts are slightly stronger, and typically produce hail
that barely reaches severe limits and/or brief microbursts (a strong
downdraft of air that hits the ground and spreads out). Brief heavy
rainfall and occasionally a weak tornado are possible. Though pulse
severe storms tend to form in more unstable environments than a
non-severe single cell storm, they are usually poorly organized
and seem to occur at random times and locations, making them difficult
MULTICELL CLUSTER STORM:
The multicell cluster is the most common type of thunderstorm. The
multicell cluster consists of a group of cells, moving along as
one unit, with each cell in a different phase of the thunderstorm
life cycle. Mature cells are usually found at the center of the
cluster with dissipating cells at the downwind edge of the cluster.
storms can produce moderate size hail, flash floods and weak tornadoes.
Each cell in a multicell cluster lasts only about 20 minutes; the
multicell cluster itself may persist for several hours. This type
of storm is usually more intense than a single cell storm, but is
much weaker than a supercell storm.
MULTICELL LINE STORM (SQUALL LINE):
The multicell line storm, or squall line, consists of a long line
of storms with a continuous well-developed gust front at the leading
edge of the line. The line of storms can be solid, or there can
be gaps and breaks in the line.
can produce hail up to golf-ball size, heavy rainfall, and weak
tornadoes, but they are best known as the producers of strong downdrafts.
Occasionally, a strong downburst will accelerate a portion of the
squall line ahead of the rest of the line. This produces what is
called a bow echo. Bow echoes can develop with isolated cells as
well as squall lines. Bow echoes are easily detected on radar but
are difficult to observe visually.
SUPERCELL STORM: The
supercell is a highly organized thunderstorm. Supercells are rare,
but pose a high threat to life and property. A supercell is similar
to the single-cell storm because they both have one main updraft.
The difference in the updraft of a supercell is that the updraft
is extremely strong, reaching estimated speeds of 150-175 miles
per hour. The main characteristic which sets the supercell apart
from the other thunderstorm types is the presence of rotation. The
rotating updraft of a supercell (called a mesocyclone when visible
on radar) helps the supercell to produce extreme severe weather
events, such as giant hail (more than 2 inches in diameter), strong
downbursts of 80 miles an hour or more, and strong to violent tornadoes.
environment is a big factor in the organization of a supercell.
Winds are coming from different directions to cause the rotation.
And, as precipitation is produced in the updraft, the strong upper-level
winds blow the precipitation downwind. Hardly any precipitation
falls back down through the updraft, so the storm can survive for
long periods of time.
edge of the precipitation from a supercell is usually light rain.
Heavier rain falls closer to the updraft with torrential rain and/or
large hail immediately north and east of the main updraft. The area
near the main updraft (typically towards the rear of the storm)
is the preferred area for severe weather formation.