Wednesday, January 07, 2009

Can it snow when it is 48 degrees?


Graupel

Answer: Yes! If you live in extreme North Alabama you may have noticed what you thought was snow. The temperature at the surface was in the upper 40's but the air was much cooler 4000-5000 feet above the surface. Snow can fall into dry air at the surface if there is a thick enough layer of cold air above the surface. That is what happened today. Technically the precipitation was graupel. Graupel is defined as a form of form of frozen precipitation consisting of snowflakes or ice crystals and supercooled water droplets frozen together. Daniel Lamb of the Huntsville NWS posted about this here.

Some pictures of the unusual event (for Alabama) were posted by James Spann at Alabamawx.com.

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