Although some scattered shower & t'shower activity could occur during the morning hours, it appears that the biggest severe weather threat will be in the afternoon/evening time period.
The 1st graphic to the right shows The Storm Prediction Center's 30% chance for severe weather within 25 miles of a point. Notice that it lowers east of Nashville. They have us in the "Slight Risk" category.
The biggest threat will be damaging straight line winds, but a few isolated tornadoes are still possible.
The 2nd graphic shows the tornado threat as "low". Although this is indeed true, don't be surprised if a tornado warning or two are issued amongst severe t'storm warnings. But it's just not one of those "super outbreak" situations.
Like many times, we have plenty of "shear" dynamics in the atmosphere to cause severe weather and tornadoes, BUT marginal "instability" (heat/moisture), and what instability we have decreases to the east.
As for rain and Trick or Treat plans, parents, it would be a good idea to have an indoor alternative. There is a slight chance we could see a temporary break between afternoon and later evening storms, but I wouldn't count on it.
On Thursday, I will be in the News 2 Storm Center tomorrow with my colleagues, so if things get bumpy, turn on News 2.
For weather geeks, the bottom graphic shows 70 knot Surface to 500 mb "Bulk Shear", 0-3km SRH values up to 500 m2/s2 (plenty high to cause rotational updrafts).
BUT CAPE values (instability) never get above 500 joules/kg (if that), and get lower the farther east you go.