The lowest winter temperatures usually occur in the middle of all continents. In the Northern Hemisphere, cold, dry air moves south from the North Pole, bringing cold weather. Storms move from west to east along the southern edge of the cold air. In the United States, winter storms produce large snowfalls in some areas. The most snow falls in the western mountains and in much of the northern region east of the Rocky Mountains.
Many winter storms bring rain to warmer southern areas.
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