LESSON 3: FRONTS
What happens along cold fronts and warm
fronts? The boundary between two air masses is
called a front. As a result, moving fronts indicate a change in the weather. On
a weather map fronts are drawn where there is large change in temperature and a
shift in wind direction. A front can also be described as the boundary between
adjacent Highs with different conditions.
On a weather map, fair weather is generally associated with Highs while
stormy weather is associated with Lows and with the portions of fronts that
extend from them. Highs and Lows are usually hundreds or thousands of miles
across. Both Highs and Lows tend to travel from west to east across the United
States, bringing changing weather as they move.
The image above shows an example of a weather map containing a warm and cold
front. A cold
front means a cold air mass is pushing into a warmer air mass, and is shown
with blue sharp "teeth" pointing the direction of the moving cold air. A warm
front means a warm air mass is pushing into a colder air mass, and is shown
with red rounded "teeth" pointing the direction of the moving warm air.
Use the map above to complete the
- This activity will assist you in interpreting weather maps on which
fronts are already identified.
Imagine that you are located at El Paso, Texas on the
1. As the cold front approaches, what changes in the sky condition
do you expect?
2. What changes in wind direction will occur as the front
3. At the time the front passes what change in temperature will
Imagine that you are located at New York City, New York on the
4. What changes will occur in the sky condition prior to the arrival
of the warm front?
5. As the warm front passes, what changes do you expect in
6. After the front passes, what changes in weather do you
The rainfall is usually different along cold fronts and warm
fronts. Along cold fronts, the air is pushed up rapidly and the front quickly
passes. The rain is often more stormy and relatively brief. Along warm fronts,
the air is pushed more slowly over the cold air mass. The rainfall is usually
more entle and extended in duration.
7. Over which city, New York or El
Paso, are thundershowers more likely to occur? Why?
8. Draw a table
similar to the one below and fill in the characteristics of Highs and Lows in
- Maps from The Weather
- Maps from Tiger Census Maps
Written by: Gene Rempel and Mike
Last Modified September 19, 1998