The air masses that have the greatest influence on weather conditions in the central United States are Continental polar and Maritime Tropical air masses.
A large volume of air in the atmosphere with uniform temperature and moisture is called an air mass.
These air masses can extend horizontally for thousands of kilometres. Vertically, they can extend from ground level to the stratosphere which is up to 16 kilometres into the atmosphere. Air masses formed on land are called continental air masses and those formed over water are called maritime air masses.
When strong winds blow, air masses are moved as a whole and when they move, they carry the weather conditions of their original source with them. This influences the weather in their new location.
If the air mass clashes with an already present air mass at the new location, it can give rise to a severe storm.
Therefore two air masses affecting weather conditions in the United States are Continental polar and Maritime Tropical air masses.
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