Risk of severe storms Sunday night upgraded to 4 out of 5. What does that mean? WSMV 4First Alert Forecast: Powerful storms expected overnight, some severe WSMV 4TN Forecast: Severe weather threat continues into Memorial Day weekend | Timeline WKRN News 2Tornado Watch in effect for parts of the Mid-South WREG NewsChannel 3Thousands without power as severe storms move through East Tennessee WATE 6 On Your Side