It's cold outside. Well-below-freezing cold. Flannel pajamas and should-I-get-a-space-heater cold.

Well then why, as motorists headed out Friday morning across parts of the Midwest, were tiny droplets of rain falling — and not freezing until they hit the ground?

asap asked Julie Adolphson, a meteorologist at the National Weather Service forecast office in Pleasant Hill, Mo.

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Question: How can it rain outside when it's below freezing?

Answer: "There's warm air aloft, where the liquid is condensing to make something that falls — in this case a raindrop," Adolphson said. "It's cold on the surface. The cold air is very shallow, so when the rain comes down it doesn't have enough time to freeze to make a snow grain or an ice pellet. It hits the ground and then it freezes. That's what an ice storm is."

Rain that fell in Kansas and Missouri on Friday morning formed at about 5,000 feet above the ground, she said, and temperatures didn't hit freezing until about 3,000 feet. "That's not enough depth for it to change into a snowflake," she said.

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Bonus question: What do forecasters mean by "wintry mix"?

"That's when you're expecting more than one type of winter phenomena," she said. "If you get a combination of two or more we call that a wintry mix."

The phenomena in question, explained by Adolphson:

— Sleet: Not necessarily liquid rain and snow together, she said. More like little balls of ice, snow grains or ice pellets, but not hail.

— Snow: The old favorite. When water freezes well above the land in temperatures well below freezing and the atmosphere remains freezing down to the surface.

— Freezing rain: Liquid raindrops, but they hit a surface that is below freezing and freeze on impact.

— Freezing drizzle: Lighter than freezing rain. Freezes on impact and makes a frozen glaze.

— Thundersnow: When a thunderstorm produces snow. "It occurs with very, very strong atmospheric dynamics," Adolphson said.

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Caryn Rousseau is an asap writer based in Kansas City, Mo., where there's ice — or is it rain? — outside her office window.

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