From the National Weather Service:

A SURFACE LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP AND MOVE ALONG THE GULF COAST SUNDAY NIGHT AND MONDAY.

COLD AIR WILL BE IN PLACE ACROSS MIDDLE TENNESSEE AS THE SYSTEM SPREADS SNOW NORTHWARD ACROSS THE AREA. THE POTENTIAL EXISTS FOR A SIGNIFICANT SNOWFALL ACROSS THE ENTIRE MID STATE FROM SUNDAY NIGHT THROUGH MONDAY.

POTENTIAL SNOWFALL ACCUMULATIONS OF ONE TO TWO INCHES MAY BE EXPECTED OVER EXTREME NORTHERN MIDDLE TENNESSEE...WITH TWO TO FOUR INCHES THROUGH THE CENTRAL PARTS OF THE MID STATE...WITH FOUR TO SIX INCHES OVER SOUTHERN AREAS.

IN ADDITION...MORE SNOW IS FORECAST MONDAY NIGHT AND TUESDAY WHICH WILL ADD MORE ACCUMULATION TO THE SNOW TOTALS BROUGHT BY THE WINTER STORM.