Weather Underground Forecast for Friday, September 14, 2012.
Expect more showers and thunderstorms to develop along a cold front that continues moving across the Central U.S. on Friday. This system will move eastward from the Great Lakes, Mid-Mississippi River Valley, and Southern Plains. By Friday night, the front will extend from the Northeast, over the Ohio River Valley, and into the Lower Mississippi River Valley. Expect widespread showers and thunderstorms to develop along this front throughout the day. Heaviest rainfall and strongest storms will develop along the Lower Mississippi River Valley as the system obtains moisture and energy from the Gulf of Mexico. However, expect lighter and more scattered thunderstorms to develop across the Ohio River Valley and into the Northeast. Temperatures will continue dropping as this front passes and pulls cooler air in from Canada. Expect more seasonable temperatures to return to the Midwest and Ohio River Valley with highs ranging in the 60s and 70s on Friday. In the North, frost and freeze warnings will remain in effect for parts of the Northern Plains and Upper Midwest as overnight lows dip into the upper 20s again. To the south of this frontal boundary, onshore flow will persist for Florida, kicking up more afternoon showers and thunderstorms across the state.
Out West, high pressure builds over the Rocky Mountains and West Coast, creating another sunny and dry day. This will maintain dangerous fire weather conditions across the Pacific Northwest, the Northern Rockies, and parts of the Desert Southwest. Temperatures in the Lower 48 states Thursday have ranged from a morning low of 17 degrees at West Yellowstone, Mont. to a high of 100 degrees at Thermal, Calif.