Chapter 20
• Meteorology
• The study of
Earth’s
atmosphere –
including the
weather
processes
• Air Mass
• VERY large body
of air in the lower
troposphere
• Temperature and
humidity are the
same throughout
the entire air mass
Types of Air Masses
• Continental
• Maritime
• Tropical
• Polar
• Arctic
• Originates over
land
• Originates over
water
• Warm
• Cold
• FRIGID!!!!
• Which air mass is
HEAVIEST????
• Which air mass is
strongest???
• COLD
• If a cold air mass
and a warm air
mass meet, who
“wins?”
• The cold mass….it
pushes the warm
air mass up and
away
• COLD
• Front
• The leading edge
of an air mass
Types of Fronts
• Cold Front
•
•
•
•
• Leading edge of a cold
air mass
• Leading edge of a warm
Warm Front
air mass
Occluded Front • A front where a cold air
mass has overtaken a
warm air mass
Stationary Front
• A front that is not
moving; whatever
weather is occurring,
stays there
Thunderstorms
• Cumulonimbus
Clouds…………
• thunderstorms…
• Only clouds that
cause t-storms
• Spark wind, rain,
thunder,
lightning….and
sometimes hail
and tornadoes
• T-storms…….
• Form in warm,
moist air
• Feed off of
warm air from
the ground
•
•
•
•
•
1 – Wind
2 – Rain
3 – Thunder
4 – Lightning
If enough
VORTEX…….
• Hail &
tornadoes
Lightning
• Negative change
from the cloud
(step leader)
starts looking for
a positively
charged object on
the ground
• Thunder is the
noise that is made
when the
connection occurs
• 5 second
rule………
• For every 5
seconds between
the lightning
strike and the
clap of thunder,
the storm is 1
mile away
• Hail……..
• If there is
enough vortex
and shear for
hail, then…..
• Tornado…………….
• Ice that comes
flying down from
the top of a
cumulonimbus
cloud and
strikes the
ground
• A funnel-shape,
violently
rotating funnel
of air that
touches the
ground
• Fujita Intensity
Scale
• Rates the
strength of
tornadoes
• Ranges form F0F5
• Squall lines
• A line of
thunderstorms
that occur out in
front of the air
mass