Dear harmaster1,
Yes. It can snow when the tempreture is below freezing, as "snow
occurs when water vapor in an air mass is cooled below freezing"
(SOURCE: Salt Institute, Snowfighters Training Program
<http://www.saltinstitute.org/snowfighting/5-snow.html>).
In fact, in order not to get sleet or "just" rain, temprature must be
bellow freezing all along the way to the ground: "Precipitation starts
in the cloud as snow. As it falls, it may travel through a layer of
air that has a temperature greater than 32 F (0 C). This layer melts
the snow into rain. If the temperature at ground level is below
freezing, then the water may refreeze in the air, and we get sleet.
Or, if the layer of sub-freezing air at ground level is thin, the
precipitation falls as rain but then freezes once it touches a
freezing object on the ground.
For snow to fall, all of the layers of air that the snow falls through
once it leaves the cloud must be sub-freezing.
The warm middle layers are normally caused by the movement of warm
fronts or cold fronts through the area. In the Southeast, temperatures
often hover around 32 F, so the form of precipitation can change all
the time. In more northern areas, the temperature is well below
freezing, so snow is a sure thing." (SOURCE: "If the temperature is 30
degrees F, why do we sometimes get snow and other times get freezing
rain?" HowStuffWorks, <http://www.howstuffworks.com/question302.htm>).
You could see more explanations on :
Jetstream site: Precipitation
<http://www.srh.weather.gov/jetstream/synoptic/precip.htm>
Precipation Types: Snow Forcasting
<http://www.met.tamu.edu/class/ATMO151/tut/snow/snow4.html>
WINTER PRECIPITATION INDICES PAGE
<http://www.theweatherprediction.com/winterwx/thicknesscriteria/>
I hoep this answered your question. Search terms:
snow temperature "below freezing"
<://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=snow+temperature+%22below+freezing%22&spell=1>
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