Weather Underground Forecast for Monday, August 13, 2012.
Unsettled weather will spread eastward into the Midwest on Monday as a low pressure system from the Central Plains advances into Illinois. An associated warm front will extend ahead of the low through the Ohio Valley, while the associated cold front trails behind and extends from the low through the Southern Plains. Moisture from the Gulf of Mexico will meet with energy from this system to produce light to moderate scattered showers and isolated thunderstorms ahead of the associated frontal boundaries and around the low, from parts of the Mid-Mississippi Valley and the southern Upper Great Lakes through the Ohio Valley and into the Southern Plains and Lower Mississippi Valley. There is a slight risk of severe thunderstorm from the Lower and Mid-Mississippi Valleys through the Tennessee and lower Ohio Valleys with damaging wind, large hail, and isolated tornado threats.
Meanwhile, additional shower activity is anticipated to the north of this region as a cold front skirts across northern Minnesota and Wisconsin.
To the east of this activity, areas of showers and thunderstorms in much of the Eastern Seaboard will taper down as the frontal system stalling across the region exits into the Atlantic and high pressure expands across the region. Expect continued shower and thunderstorm activity in Florida.
In the West, monsoon moisture will kick up areas of afternoon showers and possible thunderstorms from the central and southern valleys of inland California through the Four Corners. Meanwhile, a strong high pressure system will remain over the Southwest on Monday, resulting in another day of very hot temperatures. Daytime highs across the Dessert Southwest are expected to range from 110 to 115, while high temperatures in the central and southern inland valleys and foothills of California range from 100 to 110. Temperatures in the Lower 48 states Sunday have ranged from a morning low of 30 degrees at Stanley, Idaho to a high of 114 degrees at Thermal, Calif.