Download Weather conditions

Movement of air masses
causes weather conditions
Air masses, high and low pressure systems and
frontal boundaries cause different weather
conditions
Such as: thunderstorms, hurricanes and
tornadoes
Air Masses
Huge bodies of air that form over water or land
in tropical or polar regions
Temperature and humidity conditions in the air
mass as they form are important to the resulting
weather conditions that happen when the air
masses move
Air Mass Names
Air masses get their names from where they originate
Continental polar-form over cold land bringing cold dry
air
Continental Tropical-form over warm land and bring
warm air
Maritime Polar- form over cold oceans and bring cold
moist air
Maritime Tropical- form over warm oceans and bring
warm moist air
Fronts: place where two air masses
of different temperature and
pressures meet
As these air masses move and collide with each
other, fronts form at the boundaries between the
air masses
4 Types of fronts: Warm front, Cold Front,
Stationary Front and Occluded Front
Warm front
Warm front: Leading edge of a warm air mass
moving in to replace a cold air mass
When a warm air mass collides and rides over a
cold air mass, the resulting warm front may
produce long periods of precipitation and
warmer temperatures.
Warm Front
Warm Front
Cold Front
Cold Front: leading edge of cold air that is
pushing warm air
When a cold air mass collides and slides under a
warm air mass, the resulting cold front may
produce thunderstorms, sometimes tornadoes,
and cooler temperatures.
Cold Front
Cold Front
Stationary Front
Stationary front: boundary between two air masses
where the masses are not moving
When neither a cold or warm air mass moves at a
frontal boundary, the resulting stationary front may
produce long periods of precipitation
Stationary Front
Occluded Front
Occluded front: formed in the atmosphere when a cold
front overtakes a warm front, capturing the warm air
mass between two cold air masses
When a cold air mass pushes into a warm air mass that
is behind a cool air mass, the warm air mass is pushed
up above the cooler air masses. The resulting occluded
front may produce long periods of precipitation
Occluded Front
Front Symbols
High and Low pressure
systems
Warm air rising or cold air sinking combined
with the spinning of the Earth causes the air to
spin forming high and low pressure areas
High and Low Pressure
High Pressure
High pressure systems
usually signal more fair
weather with winds
circulating around the
system in a clockwise
direction
Low Pressure
Low pressure systems with
counterclockwise
circulating winds often
result in rainy and/or stormy
weather conditions
High and Low Air Pressure
Severe Weather: storms
Storms occur when pressure differences cause
rapid movement
Types of storms: thunderstorm, tornado, and
hurricane
Thunderstorm
A storm with thunder, lightning, heavy rain and
strong winds
They form within cumulonimbus clouds
Usually along a cold front
Tornado
A tornado is a rapidly whirling, funnel-shaped
cloud that extends down from a storm cloud
Very low pressure and strong winds cause great
damage to people and property
Likely to form in frontal areas where strong
thunderstorms are present
Hurricane
A hurricane is a low pressure tropical storm that
forms over warm ocean water
Winds form a spinning circular pattern around
the center, or eye, of the storm
The lower air pressure at the center-the faster
the winds blow toward the center of the storm