Severe Storms Possible : vimarsana.com

This all stems from an area of low pressure that will continue moving NE through the remainder of the night which will drag a cold front through the Tennessee Valley on Friday. 
There is a wide time-frame for each portion of the Tennessee Valley. In some ways that represents a level of uncertainty with this system.  This level of uncertainty tends to be common with systems that come with a Conditional Threat. The timing does reflect the onset of severe weather in different portions of the Tennessee Valley. For example: Severe weather could arrive to the I-65 Corridor between 7:00 AM and 11:00 AM Friday.