The severe threat produced from Wednesday evening will slowly shift east tomorrow into the extreme southern Ohio and central Tennessee Valleys.  A complex setup makes timing crucial Thursday afternoon.

Here’s What To Know 

The Storm Prediction Center currently has a Moderate Risk of Severe Weather posted across Western Tennessee and Northern Mississippi.  But the severe threat extends well beyond this “bulls-eye” from the Midwestern to Southeastern United States.

The severe threat will extend well beyond Tennessee and Mississippi, with damaging winds and hail also a threat for Thursday.

By tomorrow morning, leftover storms from today will begin to fizzle out across the Midwest.  This will make for a rainy morning with a few rumbles of thunder across southern Illinois and Indiana.  The true threat comes early in the afternoon, along a slow moving cold front across the Tennessee Valley.

Early precipitation can help or hurt severe potential later in the day, depending on the cloud cover and how much moisture is present.  For tomorrows setup, clearing in the early afternoon will allow the atmosphere to destabilize, a key ingredient for thunderstorm formation.  How much so will depend on how much warm, moisture-rich, air is able to be pushed northward ahead of the front.

“Severe thunderstorms potentially capable of damaging winds, isolated tornadoes, and hail are forecast on Thursday over parts of the middle and lower Mississippi Valley into the Ohio and Tennessee Valleys.” NWS Storm Prediction Center

The slow movement of the front in model runs supports this idea.  Coupled with a small lower level jet, damaging winds and hail will be possible across Tennessee, Kentucky, and southern Indiana.  Along with the wind threat, the possibility for isolated tornadoes exists across  Northern Mississippi, Western Tennessee, and Kentucky.

Lower level wind profiles show some potential of tornadoes, especially within squall lines.  These tornadoes form and dissipate quickly, making it difficult to issue warnings for.  With this is mind, the primary threat will be for damaging winds and hail with the afternoon and evening storms.

Tornadoes within squall lines often form from small “notches” in the line, called mesovorticies. These tornadoes are notoriously difficult to warn for due to their ability to form and dissipate quickly.

Overnight this line of storms will weaken, pushing east toward the Appalachian Mountains.  High pressure then settles in behind the cold front and to make for quieter conditions through the weekend.