U.S. Weekly Weather Outlook: Long-Running Heat Wave Persists as Severe Storms and Flooding Threaten the Heartland

By Orbis Weather Staff August 15, 2026

The week ahead brings little relief from what has become one of 2026’s longest-running heat waves, with dangerous heat entrenched from the Gulf Coast into the Plains and East Coast even as saturated ground across the Ohio Valley keeps flash-flood risk elevated and a stubborn severe-thunderstorm pattern targets Texas, Oklahoma and parts of the Northeast. Out west, critical fire weather continues to raise the stakes for an already record-challenging wildfire season. Here is what to expect across the country this week.

National Forecast

A broad upper-level ridge stretching from the Desert Southwest to the western Atlantic remains the dominant feature on the map, locking dangerously hot air in place across the South and Plains while keeping the storm track pinned across the northern tier of the country. That same pattern is allowing repeated rounds of thunderstorms to train over the Ohio Valley, keeping flood risk high on ground that’s already saturated from the past week’s rain. Out west, a series of weak disturbances will bring occasional gusty, dry conditions east of the Cascades and into the Great Basin, sustaining elevated fire weather. Forecasters expect this general pattern — hot and dry in the South and West, wet and stormy in parts of the Midwest and Northeast — to hold through much of the week before any significant pattern change arrives.

Severe Weather Risk

The most organized severe-weather threat this week sets up across west-central Texas and Oklahoma, where forecasters say areas of storms are likely into the middle of the week as a series of weak disturbances ride along the northern edge of the heat dome. Damaging wind and large hail are the main hazards with any stronger cells, and a few storms could also produce heavy rainfall capable of triggering localized flooding. Confidence in exact timing and coverage remains low, typical of a marginal, ridge-adjacent severe setup.

Farther east, the Northeast and parts of the Mid-Atlantic remain in a pattern prone to quick-hitting severe storms, with damaging winds, large hail and an isolated tornado risk possible as disturbances slide along the periphery of the heat dome. A secondary area of concern lingers along the Carolina coast, where daily rounds of showers and storms could turn briefly severe. Any storms that develop in these zones will be capable of producing localized wind damage and power outages.

Heat Alerts

Little relief is in sight for the South, where Excessive Heat Warnings remain in effect across southeast Louisiana, coastal Mississippi and much of Middle Tennessee and the Cumberland Plateau. Actual air temperatures are expected to push into the upper 90s to low 100s through the weekend and into early next week, with heat index values climbing into the 110s in the hardest-hit areas. Forecasters say this stretch is on pace to become 2026’s longest heat wave to date, with only marginal rain chances offering any relief and overnight lows staying in the upper 70s to low 80s, providing little overnight recovery.

The heat isn’t confined to the Deep South. Extreme heat has been spreading into the Southern Plains and mid-Mississippi Valley, with Oklahoma City and parts of Missouri, Kansas and Oklahoma forecast to see highs in the high 90s to triple digits this week. Along the East Coast, Washington, D.C., and Philadelphia are both flirting with the 90s and heat indices near 100°F, while New York City and Providence, Rhode Island, have seen heat index values in the low-to-mid 90s. Health officials continue to stress that heat remains the deadliest weather hazard in the U.S. and are urging residents to limit outdoor activity during peak afternoon hours, stay hydrated and check on elderly or vulnerable neighbors.

Snow/Cold Threats

There are no snow or meaningfully cold-air threats anywhere in the Lower 48 this week — mid-August remains solidly in the grip of summer heat, and the nation’s storm track is running well north of any location where snow would be possible. The one exception is interior Alaska, where cooler air and mountain snow have already been showing up in the high country as the state trends toward what climatologists are calling a “chilly” late summer compared to recent years, though even there conditions remain well within seasonal norms for the Arctic and Interior. Look for the first legitimate cold outbreaks and mountain snow across the Lower 48 to wait until at least September.

Rainfall Forecast

The heaviest rain risk this week remains centered on the Ohio Valley, where a Flood Watch covers parts of eastern Ohio and northern West Virginia, including Belmont, Harrison and Monroe counties in Ohio and Ohio, Marshall and Wetzel counties in West Virginia. While general rainfall totals should stay under 2 inches, localized amounts up to 5 inches are possible, and with the ground already saturated from 2 to 3 inches of rain over the prior two days, forecasters warn it won’t take much — potentially as little as three-quarters of an inch in an hour — to trigger renewed flash flooding. Elsewhere, scattered showers and storms will bring beneficial but unevenly distributed rainfall to the Southern Plains and Northeast, while the South and West stay largely dry, doing nothing to ease the ongoing heat and elevated fire danger.

Regional Breakdown

Northeast

Expect a mix of lingering summer heat and the threat of quick-hitting severe storms this week. Heat index values have been running into the low-to-mid 90s in New York City and Providence, with Philadelphia and Washington, D.C., flirting with the 90s and heat indices near the century mark early in the week before a gradual cooldown into the mid-80s by midweek. A corridor from Binghamton and Albany, New York, through Williamsport, Pennsylvania, and into northern New England carries the greatest risk of damaging wind, large hail and an isolated tornado as storms fire along the northern edge of the heat dome.

Southeast

Dangerous, prolonged heat is the headline story, with Excessive Heat Warnings in effect across southeast Louisiana, coastal Mississippi and Middle Tennessee, where heat index values are forecast to reach the lower 110s through the weekend and into early next week. Daily highs in the upper 90s to low 100s, combined with high humidity and only a 25 to 30 percent chance of rain, will keep heat-related illness risk high across the region. In the tropics, two disturbances being monitored in the Gulf and Atlantic — Invest 92 and 94L — show signs of weakening, and forecasters currently see no Gulf Coast tropical threat over the next seven days.

Midwest

Recovery remains the theme after last week’s destructive derecho and catastrophic Ohio Valley flooding. A Flood Watch remains posted for eastern Ohio into the middle of the week, with the region’s already-saturated soils raising the risk of renewed flash flooding even from modest rainfall totals. Meanwhile, heat is building in from the west, with Missouri, Kansas and Oklahoma likely to see highs in the high 90s to low 100s as the broader heat dome expands eastward.

Plains

Heat and severe storms share top billing across the Plains this week. Oklahoma City and surrounding areas are expected to see highs in the high 90s to triple digits, while forecasters flag west-central Texas and Oklahoma for the best chance of organized severe storms into midweek, with damaging wind and large hail the primary hazards as disturbances track along the ridge’s northern flank. Confidence in exact storm timing and placement remains low, but any activity that develops will be capable of quickly turning severe given the available heat and instability.

West

Critical fire weather remains the dominant concern, with the greatest risk centered over southeast Nevada into Utah, where a 40 percent probability of critical fire conditions is in play as dry, breezy weather moves through the region. That risk could extend into the Cascades’ lee and the Great Basin as multiple weak disturbances track across the Northwest. In Oregon, wildfire smoke continues to blanket parts of the state, with statewide acreage burned this season — over 2 million acres — rapidly approaching the 2024 record. Heat advisories remain in effect for much of western Oregon and southwest Washington, with highs expected to reach the 100s and as high as the 113°F in southern Oregon counties, while red flag warnings continue to be issued for areas including the southern Willamette Valley and the western Columbia River Gorge amid gusty winds and single-digit humidity.

Orbis Weather will continue tracking these developing patterns throughout the week and will issue updates as forecasts evolve, particularly for the severe weather and flood risks across the central U.S.

Compiled from: NOAA Storm Prediction Center, NOAA Weather Prediction Center, NOAA Climate Prediction Center, National Weather Service, AccuWeather, and regional television and print outlets cited below.