In photos: Days of deadly storms bring flooding fresh threats to Midwest, South

A "significant" extreme weather system that's lashed the U.S. South and Midwest for days was shifting through the Southeast on Sunday — with forecasters warning of more severe thunderstorms, tornadoes and flooding threats.The big picture: The National Weather Service said severe weather concerns would persist into Monday across portions of the Southeast from the storm system that's killed at least 18 people since it ramped up last Wednesday, with officials in Tennessee confirming 10 storm-related deaths as of Sunday. An aerial view of damage left by a reported tornado in Jeffersontown, Kentucky, on April 6. The NWS' Weather Prediction Center said there's a Moderate Risk (level 3/4) of excessive rainfall across areas of central and southern Alabama with a broader Slight Risk (level 2/4) across adjacent areas of the interior of the Southeast and the central Gulf Coast region going into the night of April 6. Photo: Leandro Lozada/AFP via Getty Images John Clayton, 56, carries his cat in a kayak as the Kentucky River begins to flood his house on April 6 in Frankfort, Kentucky. The storms had killed at least two people in the state, said Gov. Andy Beshear in in a video posted to his social media accounts. Photo: Michael Swensen/Getty Images An aerial view of damage left by a reported tornado in Jeffersontown on April 6. At least one storm-related death has been reported in Indiana and another in Mississippi. Photo: Landro Lozada/AFP via Getty Images Officials in Missouri announced the deaths of a Franklin County firefighter and the Whitewater Fire Protection District chief, both of whom were responding to storm callouts. Screenshot: Missouri Highway Patrol Group I/X Crews in Little Rock, Arkansas, clearing debris including downed trees. The severe weather killed a 5-year-old boy, the Arkansas Department of Public Safety said in an April 5 online post. Photo: City of Little Rock/Facebook Pendleton County Search and Rescue take county electricians on a boat to turn off an electrical box in a flooded park on April 5 in Falmouth, Kentucky. Falmouth, as the Licking River continues to rise. "The major river flooding is expected to continue through much of this week," per the NWS. Photo: Michael Swensen/Getty Images Downed trees and structure damage are seen after tornadoes moved through the area on April 3 in Selmer, Tennessee. While the overall rainfall threat was set to diminish on April 6, the NWS said there the threat for severe thunderstorms would exist over the coastal plain of the Southeast, "with some damaging wind potential before the front passes through." Photo: Jason Davis/Getty ImagesGo deeper: Rainstorms are getting more intense amid climate change

A "significant" extreme weather system that's lashed the U.S. South and Midwest for days was shifting through the Southeast on Sunday — with forecasters warning of more severe thunderstorms, tornadoes and flooding threats.

The big picture: The National Weather Service said severe weather concerns would persist into Monday across portions of the Southeast from the storm system that's killed at least 18 people since it ramped up last Wednesday, with officials in Tennessee confirming 10 storm-related deaths as of Sunday. An aerial view of damage left by a reported tornado in Jeffersontown, Kentucky, on April 6. The NWS' Weather Prediction Center said there's a Moderate Risk (level 3/4) of excessive rainfall across areas of central and southern Alabama with a broader Slight Risk (level 2/4) across adjacent areas of the interior of the Southeast and the central Gulf Coast region going into the night of April 6.

Photo: Leandro Lozada/AFP via Getty Images John Clayton, 56, carries his cat in a kayak as the Kentucky River begins to flood his house on April 6 in Frankfort, Kentucky. The storms had killed at least two people in the state, said Gov. Andy Beshear in in a video posted to his social media accounts.

Photo: Michael Swensen/Getty Images An aerial view of damage left by a reported tornado in Jeffersontown on April 6. At least one storm-related death has been reported in Indiana and another in Mississippi. Photo: Landro Lozada/AFP via Getty Images Officials in Missouri announced the deaths of a Franklin County firefighter and the Whitewater Fire Protection District chief, both of whom were responding to storm callouts.

Screenshot: Missouri Highway Patrol Group I/X Crews in Little Rock, Arkansas, clearing debris including downed trees. The severe weather killed a 5-year-old boy, the Arkansas Department of Public Safety said in an April 5 online post. Photo: City of Little Rock/Facebook Pendleton County Search and Rescue take county electricians on a boat to turn off an electrical box in a flooded park on April 5 in Falmouth, Kentucky.

Falmouth, as the Licking River continues to rise. "The major river flooding is expected to continue through much of this week," per the NWS. Photo: Michael Swensen/Getty Images Downed trees and structure damage are seen after tornadoes moved through the area on April 3 in Selmer, Tennessee.

While the overall rainfall threat was set to diminish on April 6, the NWS said there the threat for severe thunderstorms would exist over the coastal plain of the Southeast, "with some damaging wind potential before the front passes through." Photo: Jason Davis/Getty ImagesGo deeper: Rainstorms are getting more intense amid climate change.