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Weather
A. What is weather?
1. Defined as the short term conditions of
2.
the atmosphere.
Changes in the weather are due to the
uneven heating of the earth’s surface.
B. Atmospheric Variables
 1. these describe the
changes in the
weather.
 2. includes:
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Air temperature
Air pressure
Moisture (humidity)
Precipitation
Wind direction and speed
Cloud cover
c. The Atmosphere and Energy
 1. The SUN is the main source of energy
on Earth that drives weather changes.
 2. Weather occurs in the lowest layer of
Earth’s atmosphere called the
TROPOSPHERE.
 3. This is the only layer of earth’s
atmosphere that contains water vapor,
necessary for all types of weather.
D. Weather Forecasting
 1. Meteorology: the study of weather.
 2. Forecasting is defined as: knowing
current weather patterns and using them
to determine the future state of the
atmosphere.
 3. Weather maps are one of the most
important tools used in weather
forecasting.
E. Weather Maps
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These maps show:
1. bands of precipitation
2. HIGH and LOW pressure systems
3. fronts
F. Fronts
 1. Defined as a
boundary between
two different air
masses.
 2. Different air
masses have different
temperatures,
humidity and winds.
 3. There are warm,
cold, occluded and
stationary fronts.
G. Warm Fronts
 1. warm fronts bring: warmer temperatures
 2. lower air pressure
 3. periods of lighter precipitation that might last
for a longer period of time
H. Cold Fronts
 1. cold fronts bring: Colder temperatures
 2. higher air pressure
 3. periods of heavy precipitation that last for a shorter
period of time.
 4. associated with thunderstorms
I. Occluded Fronts
 1.occur when one
cold front overtakes a
warm front and the
two combine.
 2. leads to longer
periods of
precipitation around a
LOW pressure center.
 3. All LOW pressure
centers tend to track
towards the NE
J. Air Masses
 1. What is black and white and flat?
 2. An air mass is defined as a huge body
of air having similar characteristics
throughout:
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Temperature
Air pressure
Moisture
Wind
Continued….
 3. a panda that’s been squashed by a
truck…haha, get it? Black, white, flat?
 4. Air masses obtain their characteristics
from their source region OR the area they
sit over.
 5. Maritime (m) air masses originate over
water and are moist.
 6. Continental (c) air masses originate
over land and are drier.
Continued…..
 7. Tropical (T) air
masses originate at
lower latitudes and
are warmer.
 8. Polar (P) air
masses originate at
higher latitudes and
are colder.
 9. Combining the
moisture and
temperature terms…
Continued….
 …gives us the names of various air
masses.
 10. Names of air masses are:
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mT = maritime tropical
mP = maritime polar
cT = continental tropical
cP = continental polar
cA = ???
K. Air-mass Tracks
 1. ALL air masses,
from across the U.S.
track through a
“corridor” in the NE
making weather
prediction very
difficult in this part of
town.