Weather study guide
answer
Humidity
 Humidity is the amount of
water vapor in air.
 The air cannot hold much
more water when humidity is
high so your sweat will not
evaporate to cool you off.
Humidity

How is temperature related to the
amount of water vapor air can
hold?
 The warmer the temperature, the
more water vapor it can hold.
Humidity
 What is relative humidity?
 Relative humidity measures
how much water vapor air is
holding compared to how much
it could hold at a certain
temperature; it is written as a
percent.
Precipitation
 How does precipitation form?
 Precipitation forms when
evaporated water vapor condenses
in clouds on particles such as dust
1) sun
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2) clouds
3) evaporation
4) precipitation
5) bodies of water
6) condensation
Identify the types of precipitation
 a. rain
 b. freezing rain
 c. sleet
 d. snow
 e. hail
types of molecules
water vapor and solid
particles (dust)
High and Low Pressure Systems
High and Low Pressure Systems
 Warm air is less dense than colder
air and rises in the atmosphere.
 Rising moist air causes areas of
low pressure, creates clouds, and
is associated with stormy weather.
High and Low Pressure Systems
Cool air is more dense than
warmer air and sinks in the
atmosphere.
 Sinking dry air causes areas of
high pressure, evaporates clouds,
and is associated with fair weather

Wind forms
 Air molecules move from
areas of high pressure to low
pressure; these moving
molecules create wind.
Thunderstorms
Thunderstorms form
when warm, moist air
rises quickly and then
cold air sinks quickly.
Thunderstorms
 Three dangers of thunderstorms
include: heavy rains (flash floods),
lightning, strong winds, tornadoes,
and hail.
Thunderstorms
 Lightning is produced in a cloud
when different parts of the cloud
become oppositely charged. When
current flows between regions of
opposite electrical charge,
lightening flashes
Thunderstorms
 Thunder is caused by the
rapid heating of air around a
bolt of lightening
Tornadoes
 Tornadoes form when the up
and down movement of air in a
thunderstorm begins to move in
a circular motion.
Tornadoes
 Weather that is associated with
tornadoes includes hail and
lightning.
Tornadoes
Tornadoes
 The Fujita Scale is used to rate
tornadoes based on the wind
speed. (F-0 through F-6)
Tornadoes
 Warm moist air from the Gulf of Mexico
collides with cool air from Canada and dry
air from the Rockies. This collisions of air
mass is often triggers thunderstorms, often
very strong ones.
 Tornadoes form during thunderstorms, when
unstable hot air near the ground rises and
meets the cooler air above in the thunder
clouds.
Hurricane
 Low pressure system over the
ocean near the equator
 Hurricanes form when warm,
moist air rises quickly over
warm water.
Hurricane
Hurricane
 Typhoon in the Pacific ocean
 Tropical cyclone in the Indian
ocean
Hurricane
 Three dangers of hurricanes
include: strong winds, heavy
rains (flooding), storm surge,
and tornadoes.
Blizzard
 A severe snowstorm characterized
by strong winds and low
temperatures
Blizzard
 During a blizzard you should
stay indoors, dress warm and
be prepared
 Low pressure often brings stormy
weather, and high pressure often brings
fair weather. Which of the locations is
most likely to have clear skies?
a. Q
b. R
c. S
d. U
Q
 What kind of front does the
line with the half circles
represent?
 warm front
mm
 In what direction is the cold front
moving?
 east
 What type of weather should city
“U” be expecting?
 warmer temperatures