A significant weather pattern shift is underway, and it’s bringing with it intense, prolonged heat for millions across the central and southern United States. According to AccuWeather meteorologists, a massive dome of high pressure is building over the Plains and Mississippi Valley — a setup poised to trap heat and humidity for weeks to come.
This “heat dome” will cause temperatures to soar into the triple digits for many locations that have so far escaped the worst of summer’s heat. Cities like Dallas and Kansas City — which have yet to record 100°F days this year — are expected to break that barrier repeatedly in the days ahead.
Dallas was averaging 1.4 degrees below its normal July temperature, but forecasters say that is about to change dramatically. With multiple 100°F days expected, the city is likely to end the month near or above historical averages.
Kansas City, which hasn’t reached 100°F since August 25, 2023, is also likely to face several scorching days under the dome, according to AccuWeather Senior Meteorologist Chad Merrill.
The heat dome is driven by a northward bulge in the jet stream, locking high pressure over the central U.S. This system could meander east to west in the coming weeks, but forecasters say it may persist through much of August.
Along with the heat, high humidity will add to the discomfort. As ground moisture evaporates in areas recently hit by rain, the resulting mugginess will keep heat index values dangerously high — even during the nighttime hours. Overnight lows in many areas, including parts of Nebraska, Missouri, Texas, and Louisiana, are expected to hover between the mid-70s and low 80s, offering little relief from the daytime heat.
Officials are urging caution for outdoor workers, athletes, and anyone spending extended time outside. Heat-related illnesses become a serious risk in such conditions, and regular hydration and shaded breaks are strongly recommended.
While the Northeast will also see brief periods of heat and humidity, the core impact of the dome is focused over the southern and central U.S., where the extreme pattern may leave its mark for weeks to come.
