Which factors contribute to winter precipitation in the Midwest Region?

• A. Great Lakes and Gulf of Mexico
• B. Pacific Ocean
• C. Atlantic Ocean
• D. Arctic Ocean

Answer: (A)

Winter precipitation in the Midwest mostly comes from available moisture meeting cold air and the way that air masses move across the region. The Great Lakes supply moisture directly to the atmosphere as cold air moves over their relatively warm surface waters, creating lake-effect snow thatbuffets areas downwind of the lakes. The Gulf of Mexico provides another major moisture source: warm, humid air from the Gulf is drawn north by winter weather systems and, when it encounters cold Midwest air, it often falls as snow or other wintry precipitation.

The Pacific, Atlantic, and Arctic Oceans aren’t the primary moisture sources for Midwest winter weather. The Pacific mostly drives storms toward the western U.S., the Atlantic mainly affects the eastern U.S., and while Arctic air can bring cold outbreaks, it doesn’t supply the moisture needed for heavy precipitation.