SOME METEOROLOGICAL TERMS
The top portion of a mature thunderstorm that has the appearance of having been "blown off."
Also sometimes called a shelf cloud.
This is usually the dark, ominous looking cloud formation the precedes the passage of a
squall line or multi-cell thunderstorm formation. It is formed as warm moist air overrides
cool downdraft winds at the leading edge of the thunderstorm (the gust front).
The basic thunderstorm, which consists of one updraft and one downdraft.
Area of dust, sand, and debris that
forms near the ground at the base of a tornado.
A small area of rapidly descending air
beneath a thunderstorm. Downburst winds hit the ground and spread out, often at speeds in
excess of 100 mph. See also downdraft, macroburst and microburst.
Area within a thunderstorm where the
predominant air motion is downward. Where there is precipitation there will always
be a downdraft. Downbursts are localized areas within the downdraft of very rapidly
Generally the funnel is a visible
tornado that hasnt yet reached the ground. Funnels consist of water droplets that
have condensed due to the rapid temperature and pressure changes in the vicinity. Also
called condensation funnel.
The area near the leading edge of a
thunderstorm where downdraft winds hit the earths surface and spread out. The gust
front is the leading edge of the spreading winds. The gust front is usually found just
below or very near the arc cloud.
Large ice chunks that grow within the
thunderstorm until they are too heavy to be supported by the mechanics within the storm.
Large hailstones fall at speeds greater than 100 mph.
Area of a thunderstorm where air from
the surrounding environment is "sucked up" into the thunderstorm updraft. The
inflow area is always void of precipitation and the cloud bases are dark and flat.
A downburst with a diameter of greater
than 2.5 miles.
Downward protruding "bumps"
usually on the underside of the anvil of a thunderstorm. Mammatus ("Mama")
clouds are indicative of extreme turbulence.
A downburst with a diameter of 2.5
miles or less.
That portion of the thunderstorm where
the downdraft winds hit the surface of the earth and spread out.
A protruding cloud area above the
usually smooth anvil of a mature thunderstorm that indicates the presence of an intense
Clouds that appear to have broken off
beneath the base of a thunderstorm. Scud (fractus) clouds often may reach to near
the ground and can be easily mistaken for a funnel.
See Arc Cloud
Scud-type cloud that forms near the
base of a wall cloud and protrudes almost parallel to the earth toward the main
precipitation shaft of the thunderstorm.
Rotating area of strong winds and
rapid pressure change that sometimes forms in conjunction with a severe thunderstorm.
The area within the thunderstorm where
the predominant air motion is upward.
An area of dry clear air that often
forms between the main precipitation shaft and the rain-free base wall cloud.
A rotating cloud that forms beneath
the base of the thunderstorm behind the main precipitation shaft where some of the
inflowing air and outflowing air meet and mix. Tornadoes, if they occur, will appear to
drop out of the wall cloud.