Overview

• Over 170 million Americans face extreme heat warnings and advisories through Tuesday as the wave spans from Ohio to New England
• Cities including Cleveland, Chicago, Boston and Washington, D.C. have reported heat indices above 100°F with only minimal overnight relief
• Dozens of cooling centers have opened in major cities to shelter vulnerable groups like the elderly, children and residents without air conditioning
• A weakening upper-level ridge and an approaching front are forecast to break the heat dome by Wednesday, allowing temperatures to ease
• The National Weather Service warns that high humidity and sustained night-time lows in the 70s raise the threat of heat-related illnesses