Download Air Masses and Fronts

Air Masses and Fronts
What are the major types of air masses that
affect the weather in North America?
Air Mass
a huge body of air
w/similar temperature,
humidity, air pressure
Types Air Mass
tropical
warm, low pressure
polar
cold, high pressure
maritime
(L. mare-sea)
form over ocean, wet
continental
form over land, dry
Combinations
maritime/tropical warm, humid
Gulf of Mexico, Atlantic
move North to influence
weather in
south, central US
form over Pacific affect
weather West coast US
maritime,polar
cool, humid from
NPacific, NAtlantic
affect weather westUS
continental,tropical
continental,polar
hot, dry, summer
SW US, plains
cool,dry affect
weather all NA
How do air masses move?
front
area where 2 air
masses meet but
do not mix
causes storms &
changeable weather
Types fronts
cold front
warm front
cold, dense air
sinks bringing fast
weather changes
violent thunderstorms
After cold front
leaves
clear skies, cooler
temperatures remain
produces clouds,
rain. winter-snow
After warm front
leaves weather is
warm, humid.
stationary front
occluded front
warm front cold front
meet but do not
overtake each other,
produces rain, snow,
fog for many days
(L. up close)
warm air mass caught
between 2 cold fronts
dense, cold air moves
beneath warm front.
weather may be cloudy,
rainy or snowy.
Weather Systems
cyclones
(Gr-wheel)
area of low air pressure
produces a swirling
center of low air pressure
As air rises in cyclone,
weather produced is
storms and rain.
anticyclones
high pressure centers of
dry air.
cool air moves
downward, produces
dry, clear weather