Download Metorology 5

AIR MASSES
• Source region- Characteristics that air takes on
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from it’s place of origin.
Air Mass- A huge section of the lower troposphere
that has the same kind of weather throughout.
(named for their source region)
AIR MASSES
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Maritime Tropical: (mT) warm and moist.
Continental Tropical: (cT) warm and dry.
Maritime Polar: (mP) cold and moist.
Continental Polar: (cP) cold and dry.
Continental Arctic: (cA) very cold and dry.
AIR MASSES
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May take many days to pass one location.
Weather changes may be very slight or extreme.
Size can be up to 2000km in diameter.
They are uniform throughout.
AIR MASSES
• Air mass tracks or paths:
• If moving from the south, they move east and
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north.
From the north they move east and south.
For the most part they move from the west to
east.
Fronts and Pressure
• Cyclone : Low pressure area.
• Anticyclone: High pressure area.
Fronts
• Warm Front: the leading edge of an
advancing mass of warm air; it separates
warm air from the colder air ahead.
• A warm front moves more slowly than the
cold front.
Warm Front
• rainfall gradually increases as the front
approaches.
• Warm air is lighter and usually gets forced
upward when hitting a cold front.
Cold Front
• Cold Front: the leading edge of the
temperature drop off of colder air.
• Cold fronts can move up to twice as fast and
produce sharper changes in weather than warm
fronts.
• cold air is denser than warm air and rapidly
replaces the warm air preceding the boundary
Fronts
• Stationary fronts: is a boundary between two
different air masses, neither of which is strong
enough to replace the other.
• Usually clouds, prolonged precipitation, and
storm trains are found at these types of fronts.
Fronts
• Stationary fronts will either dissipate after
several days or dissolve into shear lines, but
can change into a cold or warm front if
conditions aloft change.
Fronts
• Occluded fronts: is formed during the process
of cyclogenesis when a cold front overtakes a
warm front.
• Thunderstorms possible, but usually their
passage is associated with a drying of the air
mass.