Dangerous Heat Wave to Build in Central U.S. Today, Expand East Through July 4th Week

Dangerous heat will build across the Plains and Midwest today. It will then expand to the East Coast through the upcoming week, bringing increasingly oppressive heat and humidity ahead of Independence Day.

A strengthening upper-level ridge will remain settled over the central U.S., while also expanding into the Great Lakes and Ohio Valley. This will bring summertime heat into full swing as temperatures across the Plains and Midwest climb into the low to mid 90s, with heat index values pushing into the 100 to 110 degree range.

Tuesday will feature similar conditions, with the core of the heat holding steady from the Midwest to central Mississippi and Ohio valleys. The edge of the hotter, more humid air will also push east toward the Appalachians. 

By Wednesday, the heat dome will become firmly established as it reaches the East Coast, bringing a noticeable increase in both temperatures and humidity from the Southeast through the Mid-Atlantic and into the Northeast. This will mark a transition to a widespread and persistent stretch of heat across the eastern United States. The hottest period of the week is expected from Wednesday through Friday when high pressure is fully anchored overhead. During this time, afternoon highs will climb into the upper 90s to lower 100s, and with the added humidity, it will feel more like 105 to 110 degrees, with a few locations briefly exceeding 110 degrees. Adding to the significant heat risk will be very limited nighttime relief, with overnight lows only falling into the upper 60s and 70s and remaining closer to 80 degrees in urban areas. 

Extreme Heat Warnings stretch from western Wisconsin and central and southern Minnesota into Missouri, including the St. Louis metro area, and northeastern Kansas. Widespread Heat Advisories are in effect from Louisiana and Mississippi to the Lower Great Lakes and as far north as a small part of southeastern South Dakota and southwestern Minnesota, as well as in parts of Georgia, the Florida panhandle, and coastal South Carolina. The Twin Cities, Ames and Iowa City, Iowa, Milwaukee, Chicago, Indianapolis, Kansas City, Mo., Memphis and Nashville, Tenn., Topeka and Wichita, Kan., Pine Bluff and Jonesboro, Ark., and Jackson, Miss., are included.

Extreme Heat Watches have also been issued for a small part of northern Mississippi and much of New Jersey into eastern Pennsylvania and into southern New England, including Allentown, Philadelphia, Trenton, and Atlantic City, N.J. and Boston.

By next weekend, the fair weather center is expected to weaken slightly but remain situated near the Mid-Atlantic Coast. This will keep temperatures on the hot side with continued humidity across the Eastern U.S. through the Independence Day holiday weekend.

If you are in one of these areas experiencing unseasonably hot temperatures, it will be important to stay hydrated and cool. Avoid exposure to the sun from late morning into the early evening. Take frequent breaks in the air conditioning or shade. Eat and dress lightly. Use sun protection if outdoors. Never leave kids or pets unattended and remember to “Look Before You Lock!” Recognize the signs of heat-related illness.