...Severe thunderstorms are possible from parts of the Southern Plains to parts of the Middle Mississippi Valley/Western Ohio Valley...
...Heavy rain possible over parts of the Lower Mississippi Valley/ Central Gulf Coast...
A quasi-stationary front extending from the Northeast southwestward to the Southern Plains will be the focus for showers and thunderstorms from the Great Lakes to the Southern Plains/Lower Mississippi Valley through Friday morning.
A wave of low pressure will move along the boundary forcing part of the front to move eastward into parts of the Eastern Ohio Valley/ Tennessee Valley by Saturday morning. The area of showers and
thunderstorms will move eastward into the Ohio/Tennessee Valleys by Friday evening, retreating to the Lower Mississippi Valley/Central Gulf Coast by Saturday morning.
In addition, rain will develop along the boundary over the Northeast and the Upper Great Lakes by Friday morning, becoming an area of light to moderate rain extending from the Northeast to the Central Appalachians.
Meanwhile, a second front will sink southward from West-Central Canada to the Upper Great Lakes/Central Plains by Saturday. the system will produce light to moderate rain over parts of the Upper Mississippi Valley on Friday moving into the Upper Great lakes by Saturday morning.
Additionally, an upper-level low the Southwest/northwestern Mexico will slowly sink farther southward into Mexico by Saturday. The cold pool of air aloft will aid in triggering showers and thunderstorms over parts of the Northern/Central Rockies moving southward to the Lower Rio Grande Valley by Saturday.