Dangerous Heat Wave to Affect Large Swath of U.S. This Week

A long and dangerous heat wave will impact a large swath of the United States this week, the National Weather Service said. Temperatures are rising ahead of the July Fourth holiday and will feel hotter due to arriving high humidity. Several days of high temperatures will settle in across the lower Great Lakes, the mid-Atlantic, and the Mississippi and Ohio River valleys.

East Coast cities including New York, Philadelphia, Washington and Baltimore will feel the heat, along with Midwestern and Great Lakes cities such as Chicago, St. Louis and Detroit. Southern cities including Dallas, Little Rock, Arkansas, and Memphis, Tennessee, will also see high temperatures.

High heat will last into next weekend across the Great Plains, southeast and mid-Atlantic. Forecasters described the event as the first widespread heat wave of the summer, impacting more than half of the country and expanding across the central and eastern U.S. Temperatures will reach well into the 90s and low 100 degrees Fahrenheit.

High humidity will lead to heat indices of 100 to 110 degrees F, and as high as 115 F. Nightly lows in the 70s F will not provide much relief. The National Weather Service advised limiting outdoor activity, staying hydrated and ensuring access to air-conditioning during extreme temperatures.

The Centers for Disease Control and Prevention said heat can impact anyone, with signs of overheating including muscle cramping, dizziness, unusually heavy sweating, shortness of breath, headaches, weakness and nausea. , especially Phoenix, Las Vegas, central Texas, and much of the southwest, were already experiencing temperatures around 100 F.

Much of the West remains unusually cool, with high temperatures running 20-35 degrees below average across portions of the Northwest and northern Rockies.