Involves sudden changes in air pressure Cause rapid air
movement Conditions that bring one kind of storm in one area often
cause other kinds of storms in the same area
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Thunderstorms Tornadoes Snowstorms Hurricanes
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Torrential Downpours Strong winds at greater than 58 mph Hail
inch diameter (or larger) Frequent lightning
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Issued by National Weather Service This means that conditions
are favorable for a thunderstorm Length is multiple hours.
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Issued By Local Weather Service Means a severe storm has been
spotted by doppler radar Usually only an hour
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A sudden spark or energy discharge, caused when electric
discharges jump between parts of a cloud, nearby clouds, or between
a cloud and the ground.
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Temperatures of over 30,000 C (much hotter than Suns surface)
Heated air expands suddenly and explosively making a sound of
thunder.
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Because light travels much faster than sound.
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Stay indoors, away from doors and windows. Avoid objects that
conducts electricity, such as metal objects and bodies of water. Do
not seek shelter under the trees. Do not use phones with cords.
Remember: Cars are pretty safe
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Tornado Alley
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A tornado is a rapidly whirling, funnel shaped cloud that
reaches down from a cloud to touch Earths surface.
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Same system that produces thunderstorms can produce tornadoes.
Late in the day, when earths surface is very warm, convection (the
flow of heat through a material, causing hot parts to rise and
cooler parts to sink) can get very strong. This can lead to a
tornado.
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Conditions are favorable for a tornado to form A tornado has
formed.
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Tornado Happenings 1. When the updraft in a convection cell is
really strong, the air rushes in from all sides at high
speeds.
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2. Air curves into a spin. This lowers the pressure even more.
Air rushes in even faster, and the pressure gets even lower, and so
on. LLike a skater who pulls her arms in close to her sides. The
tornado spins faster and faster.
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3. As the tornado gets stronger, a funnel forms that can
destroy anything in its path. The center of the tornado can reach
speeds of 500 kilometers per hour (about 300 miles per hour) or
more.
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Where Do Tornadoes Happen? Tornadoes happen where dry, cold air
masses mix with warm, moist air masses. More tornadoes occur in the
United States than in any other country, especially in the area
known as TORNADO ALLEY.
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A Famous Tornado Grand Island, Nebraska June 3, 1980
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On June 3, 1980, a series of tornadoes devastated the city of
Grand Island, Nebraska. Seven tornadoes hit within a three hour
period. The storm did massive damage and closed the city down for
three days.
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About 800 tornadoes every year in the United States. The safest
place to take a shelter in a storm shelter or the basement of a
well- built building.
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All year round, most precipitation begins in clouds as snow. If
the air is colder than 0 degrees all the way to the ground, the
precipitation falls as snow.
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Try to find a shelter from the wind. Cover exposed parts of
your body and try to stay dry.
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A tropical storm that has winds of about 119 kilometers per
hour or higher (200 miles per hour). Storm usually doesnt last for
more than 7-10 days. As it moves inland it continues to move across
the land but it begins to weaken
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Map Symbols
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Intertropical Convergence Zone The ITCZ is an area of low
pressure located roughly 5 degrees North and South of the Equator.
It is a place where air converges, rises, and condenses (forming
clouds). It is the rainiest place on Earth!
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So What Does a Hurricane Need in Order to Develop? So a
hurricane needs warm water, time to grow, and favorable upper level
winds in the troposphere. If the winds are too strong, they will
blow the hurricane apart we call that wind shear!
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A list of names from A-W (excluding Q) Alternate from male to
female 6 lists, repeated in cycle Big name storms replaced
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A hurricane poses a possible threat within the next 36 hours
Hurricane conditions expected within 24 hours
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The Saffir-Simpson Scale
http://www.nhc.noaa.gov/aboutsshws.phphttp://www.nhc.noaa.gov/aboutsshws.php
Saffir-Simpson Wind Scale and Animations
http://www.nhc.noaa.gov/surge/ http://www.nhc.noaa.gov/surge/ Storm
Surge Overview and Animations
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Best plan is to evacuate Towns have voluntary evacuation during
a watch, and some switch to mandatory during a warning. Plan early
in advance
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Board all windows Prepare Flashlights, avoid candles Stay tuned
to radio Stay indoors