Locally heavy storms stretching from the Midwest to part of the Northeast will raise the risk of flooding and travel disruptions through Tuesday.
An area of blazing sunshine and excessive heat in the Southeast states will be rimmed by a river of moisture and rounds of showers and heavier thunderstorms.
While the rainfall will be beneficial in some areas following dry conditions during May and early June, it will be excessive in others.
According to AccuWeather Meteorologist Becky Elliott, "The storms are likely to be very drenching, where an inch or more of rain can fall in an hour's time."
It's the type of rainfall that may render an umbrella ineffective without a raincoat and waterproof shoes.
Commuters from Chicago and Detroit to Pittsburgh, Philadelphia, Baltimore and Washington, D.C., should be prepared for adverse conditions.
Repeating showers and thunderstorms will bring the potential for flash, urban and small stream flooding from parts of the Ohio Valley and Great Lakes to the mid-Atlantic. Some places could receive several inches of rain through Tuesday.
In urban and suburban areas, the downpours can rapidly fill catch basins, collect in underpasses and flood basements.
While the storms will be the most extensive and strongest during the afternoon and evening hours, a blinding downpour with urban flooding could occur at any time.
The exception will be across upstate New York and central and western portions of New England, the rainfall will tend to diminish late Monday. Then, storminess will increase across these areas on Tuesday.
Parts of the Great Lakes and Northeast will get a break on Wednesday, before showers and storms return later in the week.
"The pattern shows little signs of breaking down during the week, with multiple rounds of rain and embedded thunderstorms likely," Elliott said.
In addition to the drenching nature of the storms, a few can turn locally severe.
"A few gusty and perhaps locally damaging storms can occur into Monday evening across the Ohio Valley," Elliott said.
On Tuesday, drenching, gusty and locally severe storms are possible over a larger area extending from the Ohio Valley to the mid-Atlantic and western New England.
As the Upper Midwest and Northeast deal with rounds of downpours, a pipeline of tropical rain and renewed flooding will threaten parts of Texas, the lower Mississippi Valley and southern Plains this week.