Unstable weather across the northeast quadrant of the country over the next few days...
Isolated to scattered showers and thunderstorms for the Southwestern and Southeastern states...
Some active and unstable weather is expected from the Plains to the Great Lakes as a few weak frontal boundaries sweep across these regions.
To begin with, a very weak boundary moving towards the Ohio Valley will continue to produce showers and thunderstorms ahead of it for the Ohio Valley and the Northeast. However, the best and most organized activity should remain farther north into the upper and lower Great Lakes and southeast Canada.
Behind this, additional waves of energy in the flow aloft may generate a few organized areas of convection from the Upper Midwest on Monday and into the Middle Mississippi Valley by Tuesday. Moisture with these systems remains marginal, at best, but plenty of instability and lift along the boundaries may be sufficient enough for isolated storms to contain heavy rainfall and severe weather.
Elsewhere, monsoonal flow off the tropical Pacific Ocean will continue to fuel widespread showers and thunderstorms across the Four Corners region. As usual, the best coverage of storms should occur during the afternoon and evening hours when diurnal heating is at its peak.
In the southeastern states, stormy weather is likely for the Florida peninsula and up the southeastern coast as moisture is brought onshore due to the clockwise flow around higher pressure in both the western Atlantic and the Gulf of Mexico.