The National Weather Service in East Tennessee is warning that a "significant severe weather outbreak" is possible on Wednesday.
In a graphical forecast published Monday morning, the NWS's Morristown weather forecast office said that damaging straight-line winds would be the main threat, but added that storms will also be capable of producing large hail and "potentially a few tornadoes."
The greatest risk will be from noon to 9 p.m. Wednesday, though the NWS said the timing would be refined as the event approaches.
The NWS's Storm Prediction Center in Norman, Okla., on Monday issued an "enhanced risk" area for severe weather that included Nashville, Knoxville, Chattanooga and all points in between. The enhanced risk, which is the third of five categories on the SPC's threat assessment scale, means there is a 30 percent chance of severe weather.
The SPC's enhanced risk area included a total of 75,308 square miles and a population of more than 8.5 million people, also including the cities of Birmingham and Huntsville in Alabama.
The SPC said Monday morning that a "widespread damaging wind event" is possible within the enhanced risk area.
Forecasters say a warm front will move through the region on Tuesday, helping to push temperatures into the upper 60s on Wednesday. That will set the stage for a squall line — a line of thunderstorms or broken segments of a thunderstorm line — to push through the region from west to east as a cold front approaches Wednesday afternoon.
Behind the cold front, meteorologists say another hard freeze is likely by the end of the week.