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weather patterns such as summer heat waves and winter cold spells are caused by large bodies of air called ___
air masses
when two air masses meet they form a ___ which is a boundary that separates two air masses
front
a ___ is a vertical cylinder of a rotating air that develops in an updraft of a thunderstorm
tornado
terms ___ & ___ describe the moisture characteristics of air masses
continental & maritime
if an observer sees cirrus clouds, followed later by cirrus stratus, and then altostratus they are witnessing the approach of a ___ front
warm front
___ are the most powerful storms on earth
hurricanes
terms ___ & ___ describe the temp characteristics of air masses
tropical & polar
during life cycle during life cycle of a middle latitude cyclone the process of ___ occurs when a cold front overtakes a warm front and the warm air is forced upward
occlusion
when would you expect the characteristics of an air mass would change
when it moves over a different region with different weather
a ___ air mass is cold and dry in winter & cold and dry in summer
continental
middle latitude cyclone are large centers of ___ that generally travel from west to east and cause stormy weather
low pressure
which two criteria are used to classify air masses
their temp & moisture
in the great lakes region during winter ___ air masses can cause lake effect snow
continental polar
at any given time there are estimated ___ thunderstorm on progress on earth
2,000