MISSISSIPPI VALLEY — A powerful heat dome that brought intense heat to parts of the West last week is shifting eastward, setting up a potentially dangerous stretch of weather across the Mississippi Valley, mid-Atlantic and Southeast as Labor Day weekend approaches.

The change in the weather pattern will send daytime temperatures sharply higher across a large portion of the central and eastern United States. Forecast highs are expected to reach 10 to 15 degrees Fahrenheit above historical averages through the first several days of September.

For millions of residents, the combination of unusually high temperatures and persistent heat could create difficult conditions during the final stretch of summer.

The heat will not be limited to one or two isolated locations. Several major cities are expected to experience temperatures in the 90s, with some locations potentially approaching the century mark.

Temperatures Could Approach 100 Degrees

The most intense heat is expected across portions of the Mississippi Valley and Southeast, where afternoon temperatures will climb well into the 90s.

Raleigh, North Carolina, and St. Louis could see temperatures approach 100 degrees during the hottest portion of the pattern.

Other major cities will also experience significant heat. Forecast highs are expected to reach the 90s in Cincinnati, Philadelphia, Atlanta and Washington, D.C.

The unusually warm conditions are being driven by the persistent heat dome, which allows strong high pressure to remain in place and encourages hot air to build across the region.

With temperatures running so far above normal, even people accustomed to summer heat may need to take additional precautions.

Chicago, Philadelphia and Raleigh Face Heat Waves

The persistent heat is expected to produce official heat waves in Chicago, Philadelphia and Raleigh, North Carolina.

A heat wave is generally defined as three or more consecutive days above a temperature threshold, although the threshold varies depending on the local climate.

For Chicago and Philadelphia, that threshold is 90 degrees. In Raleigh, where summer temperatures are typically warmer, the threshold is 95 degrees.

Chicago is forecast to experience its heat wave from August 31 through September 2. Philadelphia’s heat wave is expected to begin September 1 and continue through September 3.

Raleigh is forecast to endure the longest stretch, with a four-day heat wave from September 1 through September 4. The timing means several major population centers could remain under intense heat as people prepare for Labor Day celebrations and outdoor activities.

Residents Urged to Take Heat Precautions

Health officials and forecasters are urging residents to take the heat seriously, particularly during the afternoon when temperatures and the sun’s intensity are at their highest. People are encouraged to stay well hydrated and avoid prolonged strenuous activity during the hottest parts of the day.

Those who must work or exercise outdoors should consider taking frequent breaks and limiting exposure to peak afternoon heat whenever possible.

The risk can become greater when high temperatures persist for several consecutive days because overnight relief may be limited, giving the body less opportunity to recover.

Labor Day Weekend Could Begin Under Sweltering Conditions

The arrival of September will not necessarily bring an immediate end to summer-like heat across the central and eastern United States.

Instead, the heat dome is expected to remain influential through the first few days of September, keeping temperatures significantly above normal in several regions.

For Chicago, Philadelphia and Raleigh, the forecast heat waves highlight how persistent the pattern could become.

While temperatures and conditions will vary from city to city, the overall message is clear: a major stretch of heat is moving east just as Labor Day weekend approaches.

Residents across the affected areas should keep an eye on the latest local forecasts, especially if they have outdoor plans. Staying hydrated, taking breaks and avoiding unnecessary exposure during the hottest hours can help reduce the risk posed by extreme heat.

Is your area expecting unusually hot weather this week? Share your Labor Day weekend plans and how you’re preparing for the heat in the comments below.