This NOAA satellite image taken Sunday, Sept. 18, 2011 at 01:45 PM EDT shows a swath of cloud cover over the nation's mid-section as a trough of low pressure extends over the Plains. This system ... more 
This NOAA satellite image taken Sunday, Sept. 18, 2011 at 01:45 PM EDT shows a swath of cloud cover over the nation's mid-section as a trough of low pressure extends over the Plains. This system supports a wave of low pressure in eastern Kansas and an associated frontal boundary that extends through the Mid-Mississippi Valley into the Ohio Valley. These disturbances interact with moisture spreading northward from the Gulf of Mexico and stir up scattered showers and thunderstorms. To the southwest, low pressure moves through the Southern Plains, while an associated warm front lifts through Ozarks with ample moisture. Showers and pockets of thunderstorms develop in parts of eastern Texas through the Lower Mississippi Valley and the Ozarks due to these disturbances. To the north, showers and cooler temperatures develop in parts of Minnesota and Wisconsin as a cold front from the north approaches the Upper Midwest. Elsewhere, variable cloud cover remains over the Mid-Atlantic as a frontal boundary exits further away from the Coast. (AP Photo/Weather Underground) less 
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Associated Press | Photo By Weather Underground
Sun, Sep 18, 2011 4:07 PM EDT