A sharp weather pattern shift is setting up across the United States, with severe thunderstorms moving into the Mississippi, Ohio, and Tennessee valleys while dangerous heat expands across the South and West, and meteorologist Ryan Hall says the heat may ultimately become the most serious part of the forecast.
Hall, host of the meteorology YouTube channel Ryan Hall, Y’all, said the pattern from Friday, July 31 onward will feature several different hazards at once, including a conditional tornado threat in Missouri, flash flooding farther east, potentially record-breaking heat in the Desert Southwest, and another possible severe-weather setup developing over the northern Plains early next week.
The overall pattern is not expected to settle down quickly either, because Hall said the western heat dome could reload deeper into August while monsoon moisture increases in the Southwest and dry conditions begin raising drought concerns farther north.
Friday Brings Storms to Missouri and Iowa
Hall said thunderstorms will already be active across Iowa and Missouri early Friday as the recent severe-weather corridor shifts farther east into the mid-Mississippi Valley.
Nearly 11 million people are expected to fall under a marginal severe-weather risk stretching from Iowa through the Ozarks, while a second area of concern develops across the central and southern High Plains.
Hall said he is confident storms will form Friday afternoon and evening, although the harder question is which storms will become severe and how organized they will be.
A disturbance moving through the region is expected to deepen a surface low from central Iowa toward southern Illinois Friday night, while breaks in the cloud cover could allow the atmosphere to become increasingly unstable.
Hall said warm air aloft may limit some of the hail threat by melting hailstones before they reach the ground, which would make damaging winds and clusters of storms the more widespread concern.
Central Missouri could still see instances of large hail, however, and Hall said short-range models were also showing enough low-level rotation to support a tornado threat if individual storms remain organized.
The area he was watching most closely was eastern Missouri, particularly from Columbia toward St. Louis, where the strongest low-level wind shear may arrive during the late afternoon and evening.
If a supercell can remain discrete in that environment, Hall said the main tornado window would likely fall between roughly 3 p.m. and 9 p.m.
The overall severe-weather risk is not especially high on paper, but Hall cautioned that recent events have shown how even lower-probability setups can still produce tornadoes when the right storm develops in the right place.
Flash Flooding Could Become a Local Problem
Friday’s storms will also carry a heavy-rain component because atmospheric moisture is expected to run near the highest levels normally seen for late July.
Hall said a slight risk of excessive rainfall is in place, although he does not expect widespread flooding because many of the storms should move quickly.
The greater concern will be communities that happen to sit beneath repeated or especially intense downpours, where three to four inches of rain could fall fast enough to put roads underwater.
That kind of setup can be deceptive because many people may see little more than a brief storm while another town not far away deals with a much more serious flooding problem.
Farther west, Hall said upslope flow behind the front could trigger supercells in Colorado, with golf-ball-size hail and wind gusts of 60 to 70 mph possible around areas such as Denver and Pueblo.
He characterized Friday overall as a lower-end severe-weather day, but one that still deserves close attention because of the localized tornado and flooding potential.
Dangerous Heat Expands Across the South and West
While thunderstorms will receive much of the attention east of the Rockies, Hall said the heat is the more dangerous story in the broader forecast.
Heat-index values across parts of the South are expected to reach 105 to 115 degrees on Friday, accompanied by widespread major heat risk and isolated areas of extreme heat risk.
Hall warned that those conditions can become dangerous very quickly for anyone without access to air conditioning, shade, or reliable hydration.
Actual temperatures across the southern Plains are expected to reach the mid-to-upper 90s and low 100s, while the Desert Southwest faces even more extreme numbers as high pressure strengthens to near-record levels.
Phoenix could approach 115 degrees with a chance of reaching 117 or 118, while Las Vegas may challenge daily or even broader heat records.
Death Valley could approach 127 degrees.
Hall said the heat wave will also spread into Southern California, making extreme temperatures a major concern for outdoor events and anyone spending extended periods outside.
One of the more troubling parts of the forecast is that overnight temperatures may remain unusually high.
Hall said parts of the Mojave Desert may not fall below the 90s at night, meaning the body has little opportunity to recover after enduring extreme daytime heat.
That lack of nighttime relief is often what makes prolonged heat waves especially dangerous, because the stress builds from one day into the next rather than resetting overnight.
Saturday Shifts the Storm Threat East
By Saturday, Hall expects the main storm system to move into the Ohio and Tennessee valleys.
Cities including Nashville, Louisville, Lexington, Cincinnati, and Huntsville are expected to fall within the same general severe-weather corridor, with about 14.3 million people under a marginal risk.
Damaging winds should be the main hazard because the atmosphere will remain humid and unstable, although Hall said there is some lower-end tornado potential from Indiana into Middle Tennessee.
Wind shear appears relatively weak, so he expects storms to form more as messy clusters rather than long-lived supercells.
That would favor brief spin-up tornadoes rather than a more organized tornado outbreak.
The more important concern Saturday may once again be flooding.
Hall said storms could repeatedly move southwest to northeast along a slow-moving front, allowing multiple rounds of rain to pass over the same communities in Tennessee and Kentucky.
He expects the excessive-rainfall threat to remain in the slight-risk category rather than rise to a more serious level, but some places could still see significant water rises if storms repeatedly track over them.
Meanwhile, much cooler and drier conditions are expected across the Dakotas and western Minnesota, where Hall described Saturday as one of the most comfortable weather days in the country.
That relief will not last everywhere, because heat should begin returning to parts of South Dakota by Sunday.
Sunday Brings a Broad Rain Shield
Hall said Sunday’s rain map becomes much larger, stretching from the Gulf Coast all the way into the Northeast as deeper moisture moves north ahead of the system.
The area he is watching most closely is upstate New York and Vermont, where the ground remains saturated after recent heavy rain.
Albany recently set an all-time daily rainfall record of 5.45 inches, Hall noted, and even another one or two inches could cause creeks and streams to rise quickly because the soil has little room left to absorb additional water.
Out West, another strong system moving into southwestern Canada should finally break some of the northwestern heat, although Hall said gusty winds could create critical fire-weather conditions across Montana and the northern Rockies before cooler air arrives.
That contrast is part of the larger pattern flip: some areas will be moving into much-needed relief while others remain locked in either extreme heat or repeated storm chances.
Monday Could Bring a Bigger Severe-Weather Threat
Hall said the most important day in the extended forecast may be Monday, when a new disturbance and strengthening jet stream move into the northern Plains.
That setup could create a more substantial severe-weather threat from the northern Plains into the upper Mississippi Valley along a cold front.
Confidence remains limited because the event is still several days away, and Hall said timing will be critical.
If the front moves through overnight, instability could fade before storms organize, but if it arrives during the afternoon or evening, the atmosphere may have enough energy to support a more serious event.
Behind the front, temperatures in the Dakotas could fall dramatically, dropping from near 100 degrees into the 70s.
That cooler air should gradually spread southward, bringing a noticeable break from the heat across portions of the northern tier.
By Tuesday, Hall said there may be a few severe storms across the central High Plains along with another flash-flood threat over Colorado burn scars.
He was less willing to make specific severe-weather calls for Wednesday and Thursday because the models diverge on where the next disturbances will track.
The Heat Dome Reloads Into August
The part of the forecast Hall expressed the most confidence in was the continuation of extreme western heat.
Triple-digit temperatures are expected to hold from California through Utah and Arizona into the middle of next week, and Hall said the western ridge may strengthen again between August 6 and August 12.
That would renew the risk of extreme heat across California, the Great Basin, and the nearby Rockies, with both daytime highs and overnight lows threatening records.
Hall also expects the heat to expand eastward toward the Plains and Southeast later in that period.
At the same time, monsoon moisture is expected to increase across the Desert Southwest, bringing heavier rainfall that could help some dry areas while worsening flash-flood concerns over burn scars.
Farther north, Hall said a combination of dry soil and persistent hot weather could increase the risk of rapid-onset drought across parts of the Great Lakes, Great Plains, and mid-Mississippi Valley, with the Dakotas already showing signs of that trend.
His broader forecast therefore points to a country split between several competing weather regimes: severe storms moving through the central and eastern states, dangerous heat becoming entrenched across the West, and a brief northern cooldown arriving before the heat dome strengthens again.
Hall said the number he would remember from the entire forecast is 115, referring to the kind of afternoon heat parts of the Desert Southwest may experience repeatedly.
For the coming week, the storm threats will shift from one region to another, but the heat appears more persistent, and Hall warned that it could remain the most dangerous weather hazard on the map well into August.
Mark grew up in the heart of Texas, where tornadoes and extreme weather were a part of life. His early experiences sparked a fascination with emergency preparedness and homesteading. A father of three, Mark is dedicated to teaching families how to be self-sufficient, with a focus on food storage, DIY projects, and energy independence. His writing empowers everyday people to take small steps toward greater self-reliance without feeling overwhelmed.
