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WEATHER
El Nino & La Nina
El Nino
Weaken from east
Flows toward east
Mild and wet
Dry and cool
La Nina
WINDS
WARM WATER
U.S. WEATHER
AUSTRALIA
WEATHER
Strengthen from east
Move farther west
Dry and warm in South
Wet and cold in North
Mild and wet
Hurricanes
HURRICANES
WIND SPEED
SIZE
DURATION
PROPERTIES
74 mph – 286 mph
Up to 500 miles wide
2-4 weeks
How does the ocean play a role in the formation?
- A column of hot air from the Sahara that is three miles
high spreads and picks up moisture from warm water
(summer) and continues this process westward forming a
tropical storm and then a hurricane.
Rainfall Patterns
Rains
Winter
Precipitation
Summer
Dry
Little
allprecipitation
allyear
rain,
year
rain,
–
summer
all
long
from
winter
year,
all
–20°
from
dry
year
more
to
–-5°
–from
32°
infrom
summer
to8°
32°
and
8°
70°
to-15°
to20°
–
to45°
from
90°
to
and
and
45°
-30°
and
-5°
-30°
to to
-65°
70°
-15°
toto-40°
and
-90°
40° to -65°
Air Masses
- Air masses are large bodies of air that are horizontally uniform in
characteristics, like temperature and moisture content
cP
mP
mP
mT
Co
cT
Continental = dry
Maritime = moist
mT
Polar = cold
Tropical = warm/hot
Arctic = extremely cold
Fronts and Pressure Systems
•
•
•
•
•
•
•
Front – boundary separating air masses, zone of transition
Low pressure system – storm system, can travel thousands of miles and
are responsible for the majority of precipitation
High pressure system
– Semi-permanent system that occupies the central portion of the
Atlantic and Pacific
– Large systems that represent large domes of cold air that follow lows
Cold Front – cold air replaces warm air at the surface, most violent
weather
Warm Front – warm air replaces cold air at surface, usually northeast of a
cold front
Stationary front – doesn’t move, behaves like a warm front
Occluded front – when cold front “catches” a warm front, mature storm
systems
Fronts and Pressure Systems
Occluded Front
Warm Front
Stationary Front
Global Forces - Winds
Coriolis Effect
Trade Winds
The Earth’s Rotation causes
surface currents to move in curved
paths rather than a straight line.
Affected by their latitude and the Coriolis
Effect. In the tropics and poles, the winds
blow from east to west. In the temperate
climates, they blow from west to east.
Polar Easterlies
90
°
60°
Westerlies
30
°
Tradewinds
0°
Tradewinds
30°
Westerlies
60
Polar Easterlies
90
Global Forces - Water
Gyres
Deep Ocean Currents
Any large system of rotating ocean
currents, particularly those involved
with large wind movements
-Deep cold currents move water toward equator
-Cold water warms and rises to replace warm
water leaving
-Warm water travels on surface toward poles
-Warm water replaces cold water