The National Weather Service issues a warning for a prolonged and dangerous heat wave sweeping much of the US this week, with temperatures rising ahead of the July Fourth holiday.The lower Great Lakes, the mid-Atlantic, the Mississippi and Ohio River valleys and cities including New York City, Philadelphia, Washington, Chicago, St. Louis and Dallas will see daytime highs in the mid-90s to low 100s Fahrenheit and heat indices of 100 to 115 F, with nights in the 70s offering little relief.The heat is expected to persist into next weekend across the Great Plains, the southeast and the mid-Atlantic, overlapping
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National Weather Service urges limiting outdoor activity, staying hydrated and using air-conditioning or cooling centers.