Extreme heat in the Midwest and severe storms in the East: Here's what the Labor Day weekend looks like

A cold front moving in from the northeast and a developing low-pressure system over the northern plains will shape the weather across the United States over the Labor Day weekend, while a powerful heat wave maintains dangerous conditions in the central part of the country.

Severe thunderstorms and locally heavy rain in the East

Rounds of thunderstorms, some severe, with strong wind gusts and locally heavy rainfall will move slowly southward throughout Sunday and Monday. The main focus this weekend will be on the Ohio Valley, the south-central Appalachians and the mid-Atlantic coast, before shifting to the Southeast and the Gulf Coast starting Monday.

Behind the front, cooler air will break the recent heat wave in the Northeast and the Mid-Atlantic. Highs are expected to range from the mid-70s °F to the low 80s °F on Sunday, with lows dropping to 40–50 °F in New England, offering a first glimpse of fall in the second half of the weekend.

Rain and risk of flash flooding in the West

In the West, a deep upper-level trough will continue to move inland into the Northwest, favoring scattered showers and embedded thunderstorms throughout the weekend. At the same time, a southerly flow will intensify the influx of monsoon moisture into the Great Basin, where a nearly stationary front will increase the coverage of rain and thunderstorms.

The National Weather Service warns of a risk of flash flooding between southern Nevada and central Utah, particularly in urban areas, dry riverbeds and areas affected by previous wildfires. Under the influence of the trough, temperatures will remain 10 to 20 °F below normal, with subzero lows at high elevations, even as far north as California.

Storm over the northern plains and thunderstorms in the Midwest

Over the northern high plains, a surface low is expected to strengthen and deepen on Monday, just ahead of the aforementioned trough. Interaction with above-average moisture will generate a broad band of moderate to locally heavy rain on the northern flank of the system, affecting parts of the northern Rockies.

To the east of that band of precipitation, a cold front moving in from the Pacific could trigger intense thunderstorms in the northern plains, which on Tuesday would extend into the Upper Midwest as the cyclone matures and moves across the Canadian Prairies.

Dangerous heat wave in the heart of the country

In contrast, an upper-level ridge anchored over the central United States will keep oppressive heat in the south-central Great Plains and the Mississippi Valley. Heat indices will reach values of 105 to 110 °F, and record-breaking warm nights are expected across much of these regions throughout the weekend and into next week.

Authorities recommend limiting outdoor activity during the hottest hours, staying hydrated, and closely monitoring local advisories, especially if you are planning outdoor activities for Labor Day.