Tornadoes Book Report

This essay has a total of 999 words and 4 pages.

Tornadoes

A tornado is a violently rotating column of air that extends from a thunderstorm cloud to
the earth's surface. They are sometimes nicknamed twisters because of their shape and
because of what they do. The winds in the tornadoes are usually 100mph or less. In F4's
they can exceed 250mph. They usually stay on a track of a few miles or less and are less
than 100 yds. wide. For the development of tornadoes there are a few conditions required.
An abundant low-level of moisture and unstable atmosphere is required not only for the
tornado, but for a thunderstorm also. A "trigger", which is a cold front or low level zone
of converging winds, is needed to lift the moisture and the air. When the air rises , it
becomes saturated and continue to rise higher and higher. They then form in areas where
winds at all levels of the atmosphere are strong and turn clockwise with height.Some
tornadoes appear as a funnel shape and some have a churning smoky look . Some contain
multiple vortices , which are small individual tornadoes rotating around a common center.
Some can be invisible , with only swirling dust or debris at ground level as the only
indication of the tornado's presence. Tornadoes can occur at any time of the year, and
anywhere in the world. The unique geography of the US is what helps us produce some of the
most violent tornadoes because of the favorable condition's for their development . The
months with the greatest amount of tornadoes are April, May and June . Tornado seasons
vary in different parts of the US. In the Southeast the peak season is February through
April. In the northern plains it is June through August. Tornado frequency is high in the
South during late winter and in the Plains, mid-west, and Ohio Valley it is high during
early spring through summer. They can occur at any time of day but are more likely to
occur 2-7pm. The most tornadoes occur at around 5pm. In Tornado Alley, very few tornadoes
occur in the morning . In the southeast , most of the tornadoes occur during the night and
early morning hours. Most tornadoes form in conjunction with thunderstorms. Forecasters
therefore have to determine which areas are most at risk with severe thunderstorms. It is
very difficult to tell the difference between a severe thunderstorm with hail and strong
winds without a tornado and a severe thunderstorm with light rain and a severe tornado.
The computers that forecasters use to determine tornado-severe locations observe and
locate areas with strong instability and wind shear. Recent research begins to recover
that tornado formation is an extraordinary series of rapidly evolving storm scale
processes . Forecasters can determine areas where instability and wind shear coexist , and
NEXRAD Doppler Radar is one of the best indicators of impending tornado formation.Doppler
radar displays swirling cloud-level winds that often precede a tornado and can help
forecasters pinpoint areas where tornado formation may be occurring or is imminent . This
gives meteorologists valuable lead time for the issuance of watches and warnings. The
Super OutbreakThe super outbreak is one of the most infamous events that occurred in 1974.
It was one of the most violent tornadic events ever on record in the United States .The
1974 Super Outbreak spawned 148 tornadoes, the largest number of tornadoes ever produced
by one storm system. Thirty of the 148 tornadoes from this system were reported to be
classified as either an F4 or F5 (on the Fujita-Pearson scale) Before the fourteen state
rampage was over 300 people had been killed in 48 killer tornadoes. On the morning of
April 3, an area of low pressure was located in central Kansas. A warm front extended
east-northeastward through the lower Ohio River Valley. South of this front, extremely
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