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STORMS
&
PRECIPITATION
S6E4
Types of Storms:
•Thunderstorm
•Tornado
•Snowstorm
•Hurricane
Watch a Brainpop on
Thunderstorms!
• http://www.brainpop.
com/science/weather/thunderstorms/
Thunderstorm
What is it?
Small storm
with heavy
precipitation,
frequent
thunder &
lightning
Thunderstorm
How does it form?
• When warm air is forced upward along a
cold front & warm, humid air rises rapidly
• In Cumulonimbus clouds (dark, anvil-shaped)
• During Spring/Summer
Go to the Online Textbook…
• Watch Active Art…Ch 12…weather fronts
• http://www.phschool.
com/atschool/phsciexp/active_art/weather
_fronts/index.html
Thunderstorm rolling in over the city
During a thunderstorm,
which comes 1st
lightning or thunder?
LIGHTNING
MCQUEEN
IS #1!
Thunder always
follows
LIGHTNING…
Watch a Brainpop on Tornadoes!
• http://www.brainpop.
com/science/weather/tornadoes/
Tornado
What is it?
• Rapidly whirling,
funnel-shaped
cloud, reaching
from the storm
cloud to the
ground
• Brief, but deadly!
Tornado
How does it form?
• In cumulonimbus clouds with winds at
different heights
• In summer/spring
• as warm, moist
air from the Gulf
of Mexico meets
cold, dry air from
Canada
• 800 or more
tornadoes yearly
in this area
Tornado Alley
Watch a Brainpop on
Snowstorms!
• http://www.brainpop.
com/science/weather/snowflakes/
Snowstorm
What is it?
• Heavy snowfalls
that block roads
• Trap people in
their cars/homes
• Blowing wind
make people lose
their way
Blinding snow can disorient people
Snowstorm
How does it form?
• Extreme cold
• Air colder
than 32°F
ALL the
way to the
ground
Watch a Brainpop on
Hurricanes!
• http://www.brainpop.
com/science/weather/hurricanes/
Hurricane
What is it?
• A tropical
cyclone
• Winds 119
km/hr or
higher
• May be 600
km wide
Hurricane
• Forms in the Atlantic,
Pacific & Indian Oceans
• Called a Typhoon in the
western Pacific
• Hurricane Season in U.S.
from July - Nov
• Eye (center) is calm
Hurricane
How does it form?
• Begins over warm ocean water as a tropical
depression → tropical storm → hurricane
• Last ≥ 1 week
• Loses strength as it crosses land
– no water = no hurricane
Storms bring precipitation…
5 Types of Precipitation
• Rain
• Hail
• Snow
• Sleet
• Freezing Rain
Depend on the temps!
Rain
• Drizzle
• Mist
• Large drops
• Falls when the
temps are above
freezing (32°F)
Hail
• Round pellets tossed around in cumulonimbus
clouds like a rock tumbler
• During thunderstorms
• Forms at any temp
Snow
• Powdery snow falls through cold, dry air
• Clumps together as it falls through humid (wet) air
• Temps below freezing
• Water vapor in clouds made directly into ice crystals
→ SNOW!
Sleet
• Raindrops that
fall through air
that is below
freezing point
of water (32°F)
Freezing Rain
• Happens a lot in
GA in the winter!
• Raindrops fall
through cold air,
then freeze as
they hit frozen
surfaces