Air Masses
• An air mass is a large body of air that has
relatively uniform temperature and humidity
characteristics.
• If air remains over a source region long
enough, it will acquire the properties of the
surface below
• They are grouped into four categories based
on their source region
– Polar “P”- Cold
– Tropical “T”- Warm
– Continental “C”- Dry
– Maritime “M”- Wet
• These letters are combined to indicate the
type of air mass:
cP: cold, dry air mass
mP: cold, moist air mass
cT: warm, dry air mass
mT: warm, moist air mass
Fronts
• When 2 air masses meet
• Can be 100s of miles long
• Named by which mass
Overtakes the other mass
Cold Front
Cold Front
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Fast Moving
After there are cold temps
Vertical boundaries
Warm air is pushed up fast
Can lead to thunderstorms
Video from plane
Severe Storm
Warm Front
Warm Front
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Distinct Cloud Pattern
Slow Moving
Can lead to days of rainy weather
Gradual Front Line
Occluded Front
Occluded Front
• Warm air is isolated off of the ground
• Heavy Rain
• 3 different air masses
Stationary Front
Stationary Front
• Neither air mass overtakes the other
• Extended clouds or rain for days