Winter Precipitation: All Depends on the Temperature

The temperature profile during the winter months is key when trying to determine what type of precipitation will occur.  It's possible that on Thursday many Stateline residents could experience several different types of precipitation throughout the day, all depending on what the temperature is.


To understand why, we need to look at a temperature profile throughout the atmosphere.  Precipitation that occurs high up in the sky is usually frozen because temperatures are below freezing in the upper levels of the atmosphere.  But as that precipitation begins to fall, it can encounter a wide range of temperatures before reaching the surface.  If the temperature profile is below freezing from top to bottom, the precipitation will fall in the form of snow. 


Often times ahead of a storm system warm air is brought northward and can cause some of the precipitation to either partially or fully melt before reaching the surface.  If the layer of warm air isn't very thick, the frozen precipitation will only partially melt before refreezing.  This is what is known as 'sleet'. 


If the warm layer above the surface is warm enough for a longer duration in the atmosphere, then the frozen precipitation will melt, turning into rain.  Freezing rain occurs when the temperature at the surface is either at, or very close to, freezing (32 degrees).  This causes the liquid precipitation to freeze on contact.  While sleet and freezing rain are both dangerous for driving conditions, you may actually have a little better traction and control when there is sleet on the ground.  When freezing rain occurs, ice forms on surfaces causing roads to become very slippery.  If warm air is above freezing all throughout the atmosphere, rain will occur.