Download Lesson 5.1 Weather

*Refer to Chapters 10 & 11 in your Textbook
Lesson 5.1 Learning Targets:
1. Analyze how wind circulation and
coriolis develop air masses.
2. I can differentiate between the 4 types of
weather fronts.
3. I can use weather fronts and pressure
systems to make weather predictions.
Wind Circulation:
 Warm, moist air rises
 Cold, dry air sinks
 This creates a circulation of air called an air cell:
1. Hadley Cell: equator
2. Ferrel Cell: mid-latitude
3. Polar Cell: poles
Wind Circulation: *Label Map!*
 Coriolis and the air cells heating and cooling allow
the winds to travel in specific directions
 Tradewinds: occurs along the equator, carries cool
air from the northeast to the southwest
 Westerlies: occurs at the mid-latitudes (above the
Tropic of Cancer in the North), carries warm air
from the southwest to the northeast
 Polar Easterlies: occurs at the north and south
poles, carries extremely cold air from the northeast
to the southwest
Wind Circulation:
Air Masses:

An air mass is a volume of air defined by its
temperature, location, and water vapor content
 m (maritime): moist, over the ocean
 c (continental): dry, over the land
 T (Tropical): warm air
 P (Polar): cold air
 A (Arctic): coldest air
Weather Fronts:
 Weather fronts are boundaries between two air

1.
2.
3.
4.
masses of different temperature
4 Types:
Warm Front
Cold Front
Occluded Front
Stationary Front
Weather Fronts:
 Warm fronts occur when warm air replaces cold air
 The warmer air rises creating small clouds and light
rain that can last a long time, and an increase in
humidity
 Warm fronts move much slower than cold fronts
Weather Fronts:
 Cold fronts occur when cold air replaces warm air
 Cold fronts move much faster than warm, which
causes the warm air to rise vertically quickly
 This creates heavy clouds and thunderstorms that
are quick, before the air cools down and humidity
decreases
Weather Fronts:
 Stationary fronts occurs when a cold front meets a
warm front, but there is not forward movement
(“standing still”)
 Acts like a warm front creating clouds and light rain
or snow that can last a long time
Weather Fronts:
 Occluded fronts occurs when a cold front over
takes a warm front
 This happens when very
cold, cool, and warm air
collide with each other
 Acts like a cold front
creating heavy clouds
and rain or snow
Pressure Systems:
What else can we use to predict weather patterns
besides weather fronts? = Air Pressure
High Pressure System: good weather, low humidity,
low clouds, no precipitation
 Low Pressure System: bad weather, high humidity,
many clouds, rain, snow, or
cyclones
Pressure Systems: