Weather Underground Forecast for Saturday, July 28, 2012.

Expect more showers and thunderstorms across the eastern U.S. as two frontal boundaries affect the region on Saturday. One cold front will extend down the East Coast, from the Northeast to the Gulf states. Meanwhile, another cold front over the Upper Midwest is moving over the Great Lakes and into the Ohio River Valley. These systems are expected to produce widespread scattered showers and thunderstorms for most areas east of the Mississippi River Valley.

Behind this activity in the Plains, a trough of low pressure is moving off the Northern Rockies and into the Northern Plains. Flow around this system will pull moisture in from the Gulf of Mexico, feeding energy into the region. This will allow for showers and thunderstorms to develop across the Dakotas, moving into the Upper Midwest by nightfall. Some of these storms may turn severe with strong winds and large hail. South of this system, warm temperatures will continue for the Central and Southern Plains as high pressure dominates. Expect heat advisories to remain in effect as high temperatures approach 100 degrees again on Saturday.

Out West, monsoonal moisture lingers over the Four Corners and kicks up more thunderstorm activity for the Southern and Central Rockies. Heavy rainfall and severe thunderstorms are not likely in these areas.