The combination of mostly clear skies and light to calm winds will allow for temperatures dropping into the low and mid 40s for most locations. However, sheltered valleys could drop into the 30s and patchy frost will be possible in those locations, especially for areas east of I-65. Sensitive vegetation could be affected. In addition, some patchy dense river valley fog is also possible tonight. Use caution if traveling Tuesday morning, especially near typically fog prone bodies of water.