...Severe thunderstorms possible over parts of the Central Plains/ Middle Missouri Valley...
...Heavy rain possible over parts of Oklahoma/Arkansas...
A stationary front extending from the Mid-Atlantic roughly southwestward to West-Central Texas will merge with another front extending from the Middle Mississippi Valley to the Northern High Plains by Monday evening. The conglomerate boundary will yet unite with a third front moving southeastward from Ontario by Tuesday.
Showers and thunderstorms will develop along parts of the first boundary from the Mid-Atlantic to Texas through Monday morning.
Showers and thunderstorms will develop along the second front from the Central Plains to parts of the Upper and Middle Mississippi Valley that will move eastward into parts of the Great Lakes to parts of the
Southern/Central Plains on Monday.
The third front will sink southeastward from East-Central Canada to the Lower Great Lakes/Ohio Valley by Tuesday morning, while linking up to the boundary over the Central/Southern Plains.
Showers and thunderstorms will develop over parts of the Great Lakes on Monday morning moving southeastward into the Northeast/Lower Great Lakes/Ohio Valley by Tuesday.
In addition on Tuesday, showers and thunderstorms will develop along and ahead of the hybrid front extending from the Central Rockies to parts of the Lower Mississippi Valley to the Mid-Atlantic/Northeast.
Furthermore, upper-level energy will also aid in triggering showers and thunderstorms over parts of the Gulf Coast through Tuesday.
Monsoonal moisture and diurnal heating will produce scattered showers and thunderstorms over parts of the Southern/Central Rockies and the Great Basin.