Published July 04, 2012
High heat remains the top weather story for the nation this Independence Day as high pressure persists across the Plains and East. Daytime temperatures will once again climb well into the 90s and lower 100s this afternoon, while heat index values range from 100 to 110 degrees.
Expect a variety of Heat Advisories, Excessive Heat Watches, and Excessive Heat Warnings to remain in effect, especially across the Midwest. Residents are encouraged to take extra precautions while outside this holiday to reduce the risk of heat exhaustion and heat stroke.
In the East, the hot and humid airmass and high instability over the region will continue chances of daytime showers and thunderstorms in the Eastern Valleys, Mid-Atlantic, and Southeast through the afternoon and evening. Additional activity will develop to the north, as the cold front in the Upper Mississippi Valley advances eastward and a warm front lifts through the Northeast. Showers and thunderstorms are anticipated ahead of the fronts, across the Great Lakes and the Northeast.
To the west of this activity, the frontal system in the Northern High Plains will advance into the Northern Plains with showers and thunderstorms. Chances of showers and thunderstorms will spread into western Minnesota Wednesday night as the associated cold front advances eastward.
Further west, monsoon moisture streaming in across the Southwest will maintain chances of scattered showers and afternoon and evening thunderstorms in the Four Corners. Temperatures in the Lower 48 states Tuesday have ranged from a morning low of 35 degrees at West Yellowstone, Mont. to a high of 104 degrees at Smyrna, Tenn.