Overview

• A stationary high-pressure system in the upper atmosphere is trapping heat and Gulf moisture to form a heat dome that will persist into next week.
• Daytime highs are forecast in the 90s to low 100s Fahrenheit with overnight lows in the mid-70s from the Great Lakes to the East Coast.
• The National Weather Service has issued category 4 heat-risk warnings for Nebraska, Kansas, Iowa, Wisconsin, Missouri and Illinois ahead of the weekend surge.
• Elevated humidity from Gulf moisture and Midwest crop “corn sweat” is boosting heat index values and straining the body’s ability to cool itself.
• Forecasts predict record highs of 100°F in Denver, 96°F in Chicago, 99°F in Washington D.C. and 96°F in New York Central Park.