Much of the United States remains under dangerous heat wave alerts as widespread, dangerous temperatures continue Sunday and into the week. Parts of the Southeast coast will bear the brunt of the sweltering conditions.

The most intense heat is expected from Savannah, Georgia, to Virginia Beach, Virginia. Heat indices—which reflect how hot it feels when humidity is factored in—are forecast to range between 108°F and 116°F in this corridor.

The Midwest will also face oppressive conditions on Sunday. From Lincoln, Nebraska, to Minneapolis, residents can expect “feels-like” temperatures between 97°F and 111°F, continuing a stretch of stifling heat.

Charleston, West Virginia, and St. Louis, Missouri, are both under extreme heat warnings on Sunday, with forecasted heat index values ranging from 102°F to 112°F, bringing hot and humid conditions.

Sweltering Conditions Continue Across the U.S

Heat advisories have been issued for several major cities in the U.S, including Dallas, Texas; Oklahoma City, Oklahoma; Indianapolis, Indiana; Tampa, Florida; Little Rock, Arkansas; Kansas City, Missouri; and Washington, D.C. In these areas, heat index values—which reflect the effect of temperature and humidity—are forecast to range from the upper 90s to as high as 110°F.

Heat advisories are forecast for Monday and Tuesday along parts of the I-95 corridor, from Boston to New York City, with feels-like temperatures ranging between 95°F and 105°F. Conditions may persist through Tuesday, increasing the risk of heat-related illnesses.

Heat Wave to Grip Eastern U.S. Through Midweek

life-threatening heat and humidity are forecast to persist across the eastern half of the United States through Wednesday, as a prolonged heat wave continues to intensify.

Major cities including St. Louis, Memphis, Charlotte, Savannah, Tampa, and Jackson, Mississippi are expected to experience actual temperatures in the upper 90s to low 100s. With tropical moisture settling in across the region, heat index values what it actually feels like, are projected to climb to 105°F to 115°F for multiple consecutive days.

These conditions pose elevated risks for heat-related illness.

Nighttime and early morning hours are unlikely to offer relief, with lows expected to remain in the 70s or higher.

Extreme Heat Wave Risk and Severe Thunderstorm Watches in Effect

Between Monday and Wednesday, large areas of the Southeast are expected to face the highest level of extreme heat alert, rated 4 out of 4 , including major cities such as Atlanta, Charlotte, Jacksonville, and Tallahassee, Florida.

At the same time, parts of southern and central Minnesota and eastern South Dakota are under a severe thunderstorm watch until midnight. Areas in northern Minnesota and northwestern Wisconsin remain under a severe thunderstorm watch until 1 a.m..

Storms and Flight Disruptions Expected Sunday

Later Sunday, additional severe storms are possible across parts of Minnesota, Wisconsin, and Michigan’s Upper Peninsula.

Meanwhile, as thunderstorms move into the Northeast, widespread travel disruptions are occurring. As of 9:30 p.m. ET, 1,105 flights have been canceled nationwide, and 8,320 flights are delayed.