Therefore, significant snowfall at such very low temperatures is rare. Decker of the Oregon Climate Service at Oregon State University offers the following: "The maximum concentration of invisible water vapor which can occur in air decreases to extremely low values at very cold temperatures. Most clouds form through a process called expansion cooling.
First, a mass of air rises, causing it to expand because of the lower atmospheric pressure. Expansion causes the air to grow cooler, which reduces the amount of water vapor it can contain. The 'excess' vapor condenses out into a cloud. Hence, the clouds that form at colder temperatures--if any form at all--contain much less suspended water in the form of ice crystals, the starting sites for snow crystal formation.
Water vapor condenses out of the cold air to form a cloud. Whether the cloud can produce snow depends partially on how cold the air was when it formed. Clouds that form at cold temperatures contain fewer ice crystals because the air had less water to give. Ice crystals are needed to serve as nucleation sites to build the larger crystals we call snowflakes.
If there are too few ice crystals, they can't stick together to form snow. However, they can still produce ice needles or ice fog. At truly low temperatures, like degrees Fahrenheit and Celsius the point at which the temperature scales are the same , there is so little moisture in the air it becomes extremely unlikely any snow will form.
The air is so cold it's not likely it will rise. If it did, it wouldn't contain enough water to form clouds. You could say it's too cold to snow. Meteorologists would say the atmosphere is too stable for any snow to occur. Actively scan device characteristics for identification. Use precise geolocation data. It sounds like nonsense because it is nonsense. Snow can occur even at incredibly low temperatures as long as there is some source of moisture and some way to lift or cool the air.
There's one sliver of truth in the myth, however, in that very cold temperatures are often associated with dry air, in which you won't get snow. It's the dry air that prevents the snow, however, not the temperature. Wind chill advisories have been issued for most of the midwestern United States. Snow fell in Florida. Serreze says that, technically speaking, anything under 32 degrees Fahrenheit is conducive to snowfall.
Snow is made with a relatively simple recipe. All it takes is water vapor, cloud condensation nuclei , and an uplift mechanism. This week, the Eastern seaboard has had all the ingredients.
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