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LACEMOP
Factors that
Shape Weather
Weather & Climate
Weather : a condition of the
atmosphere in one place during a
short period of time
Climate: weather patterns typical
for an area over a long period of time
Latitude
The influence of latitude on climate is part of the
Earth-Sun Relationship
 The sun’s direct rays fall upon Earth in a
regular pattern
 This pattern correlates w/ Latitude Zones
 Within each zone, the climate follows
general patterns
Earth-Sun Relationships
Air Masses
Air masses take on the “weather” of the place
from which they came.
-a front — most weather changes are
caused by these.
-Convectional Precipitation:
- Typical of hot climates
- Convection occurs after morning sunshine
heats warm, moist air. Clouds form in the
afternoon and the rain falls.
Fontal Precipitation — when 2 fronts of
different temperatures meet.
Warm air forced upward by heavier, cool air.
Rising warm air cools = precipitation
Most common type
Continentality
Large bodies of water have a
moderating effect on land temperatures.
Why? Land and water absorb and store
energy at different rates.
Land changes quickly — water more
slowly.
Opposite
air blows off the water and moderates
land temperature.
Elevation
-The earth’s
atmosphere thins
as altitude increases.
Thus: as elevation increases,
temperature decreases
~ b/c thinner air retains less heat.
- Even in sunny places, mountains are
cold, snowy places year-round.
Mountain Barriers
• Can block air masses & cause precipitation.
Mountain Barriers
•Orographic Precipitation: warm moist air
forced upward when passing over a mountain.
Warm winds cool as they rise over the
mountains and clouds form.
•Windward: mountain side which faces the
ocean
• Leeward: mountain side which is in a “rain
shadow” (no precipitation received)
• Air is warm and dry on the Leeward side
Ocean Currents
• Help to distribute heat
• Carry warm water from tropics to poles
and return cold water to the Equator
• Winds affect current movement
• Air masses take on water temperature
Wind Patterns
Trade winds -- blow from the
northeast toward the Equator
and from the southeast toward
the equator
Wind Patterns
Westerlies – prevailing winds
in the mid-latitudes blow
diagonally west to east
Wind Patterns
Polar Easterlies – blow
diagonally in the high latitudes
east to west—pushing the
cold air toward the mid
latitudes
Pressure & Wind
•Rising warm air
= low pressure
•Falling cool air
= high pressure
• Wind moves high to low
• Movement from equator to
poles and back
Wind Patterns
•Coriolis Effect: rotation of
the earth bends the patterns
of the wind