Term
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Definition
bodies of air that has a particular set of temperature and moisture characteristics
formed in specific regions |
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Term
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Definition
| areas where an air mass acquires its characteristic properties of temperature and moisture conditions |
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Term
Tropical vs. Polar air masses
Temperature |
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Definition
tropical (T) - warm
polar (P) - cold |
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Term
Continental vs. Maritime air masses
Moisture Conditions |
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Definition
continental (C) - dry
maritime - humid |
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Term
cP
Weather Associated with air Masses |
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Definition
form in northern Canada and the interior of Alaska and the Arctic
winter: clear skies and cold temperatures
summer: cool and dry
low precipitation, except for lake effect snows |
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Term
mP
Weather Associated with air Masses |
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Definition
Pacific
originates as a continental polar air mass in siberia, and picks up moisture as it moves across the north pacific
drops most of their moisture due to orographic lifting in the western mountains
Atlantic
forms off the east coast of Canada
Cyclones crossing New England can draw moisture to create...? |
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Term
cT
Weather Associated with air Masses |
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Definition
forms in SW US desert regions
hot, dry air
has little influence outside of its own region |
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Term
mT
Weather Associated with air Masses |
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Definition
originate in the gulf of Mexico, Caribbean Sea, or Atlantic Ocean
warm, humid, and unstable
source of most of the precipitation in the easter 2/3 of the US
summer: high temperatures and oppressive humidity |
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Term
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Definition
boundaries that separate air masses of different densities
can form between any two contrasting air masses
narrow
frontal surface slopes at a low angle so that warmer air overlies cooler air |
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Term
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Definition
warm air movies into a region of cooler air
friction with the ground slows the advance of air at the ground relative to air aloft
gently sloping boundary between 2 air masses
rising air forms clouds and light to moderate precipitation over extended periods
if the warm front is unstable and temperature differences are great, cumulonimbus clouds and thunderstorms occur |
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Term
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Definition
forms as cold air actively advances into an area of warm air
Advance more rapidly
Steeper slopes and higher velocity lead to more violent weather patterns
Rapid release of latent heat in the rapidly rising air lead to heavy downpours and high winds. (cumulonimbus clouds)
Precipitation is heavy but short
Air behind the cold front is dominated by subsiding and cool air mass – leads to clearing of skies |
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Term
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Definition
An active cold front overtakes a warm front
Advancing cold front wedges warm front upwards
A new front emerges between the advancing cold air and the air over which it is gliding
Weather is complex |
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Term
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Definition
Occur when neither warm nor cold air advances
These conditions can last for days, producing Altocumulus clouds
Temperatures remain stagnant, winds are gentle, and precipitation is light to moderate |
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Term
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Definition
Wind speed > 119 kilometers (74 miles) per hour
Rotary cyclonic circulation
~ 500 km in diameter
Forms over warm, tropical water from energy from condensing water vapor |
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Term
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Definition
| cumulonimbus low pressure |
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