A storm that brought severe winter weather to the central Rockies and central High Plains is forecast to bring an outbreak of strong thunderstorms to portions of the Midwest and South from today until Thursday, bringing the potential for tornadoes, damaging winds, and large hail. Heavy rain could also trigger pockets of flash flooding.

Regarding this activity, the National Oceanic and Atmospheric Administration (NOAA) reports (as of March 16 at 2:21 pm EDT):

Summary: A regional outbreak of severe storms is expected Wednesday into Wednesday night across portions of the lower Mississippi Valley into Alabama. Widespread severe storms capable of producing tornadoes (several of which may be intense), very large hail and intense damaging wind gusts are expected. More than one round of severe storms are possible across parts of Mississippi into Alabama during the afternoon into the overnight hours.

• Storms will be ongoing Wednesday across central AR into northern MS/AL and will pose a threat mainly for large hail. However, conditions will become more conducive through the morning that will increase the risk for damaging wind gusts and a few tornadoes. 
• Further south across eastern OK into eastern TX, a line of supercells and lines of storms are expected to develop as they move into AR and approach the Sabine Valley. All severe hazards are expected with this activity from Wednesday morning into the afternoon. This severe risk will likely continue into Wednesday night across Alabama and vicinity continuing into Thursday further east.
• Multiple rounds of intense, severe storms will be possible, mainly across MS/AL on Wednesday afternoon into the overnight hours.
• Storms will intensify across central and eastern AR/LA during the late morning/afternoon. Fast storm motion will support widespread damaging wind gusts with some greater than 75mph expected. Large hail (some greater than 2 inch in diameter) is also expected with this activity, especially from the AR/MO border into northern LA, southwest TN and northern/central MS.
• Further east across northeast LA into MS and AL a more concerning scenario appears possible. Most forecast models agree that a round of afternoon thunderstorms are expected and will have an opportunity to remain more discrete and could quickly become a supercell capable of producing strong (EF2+) tornadoes.
• Intense supercells are expected to advance eastward across MS and into AL overnight. This will bring a second round of significant severe storms capable of intense tornadoes, large hail and intense damaging winds across much of MS/AL. 
• If these trends are maintained, an upgrade to a High risk could be necessary in future outlook updates tonight due to the threat for strong (EF2+) tornadoes.

NOAA also advises that now is the time to review severe weather safety plans, and ensure multiple ways to receive severe weather watches and warnings.

Read more at the National Weather Service and the Weather Channel.