Download E.ES.07.74 Fall 08a - Eastern Michigan University

Julie Glowski
Ahlam Baydoun
Fronts, Air Masses, and Weather
Standard: E.ES.07.74 Describe weather conditions associates with frontal boundaries (cold,
warm, stationary, and occluded) and the movement of major air masses across North America
using weather map.
Grade Level: 7
Objectives
After completion of the lesson, students will be able to:
- Recognize weather conditions associated with frontal boundaries (warm, cold,
stationary, and occluded)
- Describe air masses and their movement across North America
- Use map to show movement of fronts and the associated temperature change
List of Materials
- Colored Pencils
- Isotherms, Fronts, & Data maps
- Computer
- Projector
- Power Point Presentation
- Worksheet
- Pencil
Previous Knowledge
- Understanding of H and L pressure areas
- Know Isotherms and how to locate it on a weather map
- Know and understand typical temperatures in relation to equatorial and Polar Regions
Engage the Learner
Use two pictures, one showing someone dressed for warmer conditions and one
showing someone dressed for cold conditions. Ask class what normal clothing would suffice for
November weather. Once answers are in, remind them of the recent warm weather that
allowed people around our area to wear shorts and flip flops in November.
Briefly tell them that the unusually warm weather was caused by a warm front passing
over the area.
Explore the Content
Teacher will present power point slides that include maps, tables, and important
information on fronts, air masses, and weather.
Explain the Content
1. air mass
a. Define an air mass- An air mass is a large body of air with similar temperature
and humidity. Point out that it doesn’t mean it’s the same temperature all
over that area rather it could be below average or above average throughout
the air mass
b. Name and Describe the different air masses affecting north America
i. cP- cold and dry
ii. cT- hot and dry
iii. mP- cool and moist
iv. mT – warm and moist
c. Air mass classification (show table 8.1)
i. Polar (P) or Tropical (T)
ii. Land/Continental (c)
iii. Water/Maritime (m)
d. Air Mass Map
i. Show all air masses and the source region
ii. Air masses get the characteristics of that region
iii. Air masses don’t stay at region they move
iv. Source region- the longer the air remains stagnant over its source
region , or the longer the path over which air moves the more likely it
will be to acquire properties of the surface below.
2. Fronts
a. Reference back to introduction picture and re-emphasize on how unusual
warm weather took place in November due to a warm front.
b. Define Front Boundary- zone separating air masses
c. Introduce the four different surface fronts that form at the border of air
masses
i. Cold front- occurs where cold air advances
ii. Warm front- occurs where warm air advances
iii. Stationary front- occurs at the boundary of 2 stationary air masses
iv. Occluded front- occurs when a cold front overtakes a warm front
d. Use the front key to show how fronts are depicted on weather map
e. Engage students by asking for volunteers to identify the different front
f. Show an isotherm, front, and data map to show the direction of air
associated with a front.
g. Discuss the different weather conditions associated with frontal boundaries
i. Cold fronts- heavy rain or snow showers, sometimes thunder and
lightning
ii. Warm Fronts- Drizzle or light rain
iii. Occluded- light, moderate, or heavy continuous precipitation or
showers
iv. Stationary fronts- wide variety of weather which includes prolonged
precipitation.
Activity
Each student will be provided with Isotherms, Fronts, and Data map for three
consecutive days. On each day they will color the isotherms according to their temperature. On
third day students will compare their three maps and will see the cold front moving across N.
America from the west to the east bringing cold temperatures.
Assessment
Students will complete a study sheet. They will be able to match up the different
weather conditions with the correct frontal boundary. Students will explain the change in
temperature they saw on their colored maps. Students should be able to see that as the cold
front moved across N. America the temperatures became lower.
Resources
-Essential of Meteorology, C. Donald Ahrens. Fifth Edition
- Dr. Kovacs lecture notes, Eastern Michigan University, Meteorology ESSC 311
- http://www.ametsoc.org/amsedu/dstreme/
- www.fas.org/irp/imint/docs/rst/imint/docs/rst/sect14/airmasses_schem.jpg