Weather Underground Forecast for Monday, July 02, 2012. High heat remains in the forecast for the East on Monday as a broad ridge of high pressure remains the prevailing weather feature of the region. This system will span from the Four Corners eastward, allowing temperatures in much of the region to rise well into the 90s and 100s. Expect a variety of heat advisories and excessive heat watches and warnings to persist as heat index values reach into the triple digits. Residents in these advisory areas are encouraged to take proper precautions against the heat. Meanwhile, a frontal boundary will remain situated across the Ohio Valley while the tail of a cold front extends through the Mid-Atlantic. This will allow areas of showers and chances of thunderstorms to form near the boundary during the afternoon and evening hours. Much of the Mid-Atlantic will be at slight risk of severe thunderstorm with hail and damaging wind gusts. In the Plains, a frontal system form the West will move into the Northern Plains, spreading chances of showers and thunderstorms into the Upper Midwest. There is a slight risk of severe thunderstorm development from the eastern Dakotas through the western portions of Michigan¼'s Upper Peninsula. While the main concerns with severe storms in these areas are damaging wind gusts and hail, localized tornadoes can not be ruled out. In the West, monsoon moisture over the Central and Southern Rockies will increase chances for showers and thunderstorms. Temperatures in the Lower 48 states Sunday have ranged from a morning low of 33 degrees at West Yellowstone, Mont. to a high of 108 degrees at Smyrna, Tenn.