While a widespread severe weather outbreak is not anticipated, rain capable of causing travel disruptions and storms strong enough to knock down trees will push across the southern United States into Monday.
As the coolest air of the season so far advances eastward, moisture from the Gulf of Mexico will be wrung out in the form of torrential downpours and locally gusty thunderstorms.
The thunderstorms will erupt well ahead of and along the leading edge of the cool air.
For most locations, the storms will merely be briefly heavy and gusty. However, some communities can be hit with damaging wind gusts that break tree limbs and cause sporadic power outages.
A couple of the strongest storms can produce a brief tornado.
"The greatest risk for an isolated tornado will generally be limited to within 50 miles of the Gulf coast into Monday afternoon," according to AccuWeather Lead Storm Warning Meteorologist Eddie Walker.
"The risk will shift from southeastern Louisiana on Sunday to northern Florida on Monday," Walker said. "There's a remote chance of a tornado as far north as South Carolina on Monday as well."
By far drenching rain will be the most common occurrence during the transition to cooler weather. Locally heavy rain is forecast during the thunderstorms, along the leading edge of the cool air and accompanying the first several hours of the cooldown.
The rain can be heavy enough to slow travel. Street and highway flooding may occur in areas that drain poorly.
The combination of rain and poor visibility may force motorists to slow down on the highways as many head home from weekend football games and begin their new week of work and school.
Minor airline delays are possible on Sunday in Houston, into Sunday night in New Orleans and Nashville, and Monday in Atlanta and Charlotte, North Carolina.
In the wake of the rain and storms, daytime temperatures will be slashed by 10-20 degrees Fahrenheit and nighttime temperatures will be cut by 15-30 degrees this week.