Air Masses and Fronts
Air Masses:
 Air mass is a large body of air that has similar temperature and
moisture throughout.
 An air mass gets its moisture and temperature characteristics from
the area over which it forms. These characteristics are represented
on maps with a two-letter symbol.
(Overhead – p.44 in your text)
Resulting weather from these air masses:
Air Mass
Maritime polar
Continental polar
Maritime tropical
Continental
tropical
During the
Winter
Brings rain and
snow
Brings extremely
cold weather
Bring mild, often
cloudy weather
During the
Summer
Brings cool, foggy
weather
Brings cool, dry
weather
Bring hot and
humid weather,
thunderstorms,
and hurricanes
Does not affect the Brings clear, dry
weather
and very hot
weather
Fronts:
 A Front is the boundary that forms when two different air masses
meet.
 Weather at a front is generally cloudy and stormy.
There are four different types of fronts:
1. Cold Front – a cold air mass meets and displaces a warm air mass.
Can move fast producing thunderstorms, heavy rain, or snow.
2. Warm Front – a warm air mass meets and overrides a cold air
mass. Usually brings drizzly precipitation.
3. Occluded Front – Faster moving cold air mass forces the warm air
mass up because it is slower moving. Brings cool temperatures and
warm precipitation.
4. Stationary Front – A cold air mass meets a warm air mass and
little horizontal movement occurs. Usually brings drizzly
precipitation.
(Overheads – p.46-47 of your text)
Map symbols for Fronts:
Warm Front
Cold Front
Stationary Front