September could bring a sharp change in the weather pattern across the United States, with expanding heat, several chances for severe thunderstorms, possible bursts of cooler air and renewed questions about tropical activity all developing under an increasingly strong El Niño pattern.
Meteorologist Max Schuster, host of the YouTube channel Max Velocity – Severe Weather Center, said the opening weeks of September may be especially unsettled as very warm Pacific waters continue to influence the broader atmospheric pattern. He expects unusually hot weather to dominate much of the central and eastern United States at first, while storm systems remain active farther west and additional fronts begin moving across the northern states.
Schuster said Pacific temperatures are running extremely warm and could eventually support what he described as a “super El Niño,” with the waters continuing to heat up over the next several months. That does not point toward one single kind of weather everywhere, but it could help create a month filled with major temperature swings and several opportunities for storms.
Heat Dome Expands Across The Country
The most immediate concern heading into September is a large area of high pressure stretching across the southern Plains and gradually expanding farther north and east.
Schuster said temperatures will rise sharply around the Mississippi River Valley during the first several days of the month, with parts of Illinois and Iowa potentially reaching the 90s and even the 100s in some locations. By the middle of the week, the heat dome could stretch from Arizona toward the Carolinas.
Later in the week, that same ridge may expand toward Minneapolis, Chicago and possibly Michigan, allowing the heat to spread much farther north than it typically would at this point in the calendar. Schuster believes some places could challenge record-high temperatures as the high-pressure system strengthens.
The contrast across the country is notable because while the central and eastern states deal with building heat, the West Coast is expected to remain under a much different pattern. A dip in the jet stream should keep temperatures cooler there while helping produce rain and storms across portions of the Four Corners and eventually California.
Schuster cited the Climate Prediction Center outlook as showing above-average temperatures favored across much of the Great Plains, Midwest and Southeast during the first week of September, while areas from Seattle toward San Francisco have better chances of running cooler than normal.
Severe Weather Threat Returns
The heat will not be the only concern during the opening days of the month.
Schuster is also watching several rounds of thunderstorms that could affect the northern Plains, Midwest, Northeast and eventually parts of the Ohio Valley. The first risks are expected to remain fairly limited, but the environment could become more volatile as stronger disturbances move through.
For Monday, August 31, he said a storm system moving into the Midwest could support isolated severe thunderstorms around Wisconsin and areas east of Minneapolis. He cautioned that storm development is not guaranteed, but any thunderstorm that manages to organize could potentially produce hail, damaging winds and perhaps an isolated tornado.
A large amount of instability is expected in the region while a low-pressure system strengthens farther north in Canada, placing some of the strongest wind shear nearby. That combination is why Schuster believes even a relatively small number of storms could become important if they form.
Tuesday appears quieter overall, although isolated storms around Sioux Falls or Minneapolis could still produce strong winds.
The larger concern arrives Wednesday, when Schuster expects a stronger system to move toward the Northeast. He said northwesterly flow may support a more significant damaging-wind threat, while hail and tornadoes could also be possible.
That Wednesday setup stands out because severe weather arriving from northwesterly flow can sometimes organize quickly, especially when strong winds aloft overlap with warm and unstable air. Schuster did not present the event as certain, but his forecast suggests it is one of the more important periods to watch during the first week of September.
Another Storm System Follows
The unsettled pattern may continue almost immediately afterward.
Schuster said another storm system could cross the Midwest by Thursday, bringing another round of severe-weather possibilities across Iowa, Minnesota and Wisconsin, with Illinois potentially becoming involved as well.
By Friday and Saturday, surface high pressure is forecast to build around the Great Lakes, but he does not expect that to completely eliminate storm chances. Isolated severe thunderstorms could still develop within a broad corridor extending from around Minneapolis toward Atlanta.
Another system moving across California during the middle of the week may also help set the stage for storms farther east later in the week, with activity potentially shifting from the northern Plains toward the Midwest by Friday and Saturday.
Taken together, the forecast does not necessarily point to one continuous severe-weather outbreak. Instead, it suggests several separate opportunities for storms, which could make the first week of September feel unusually active even if individual events remain localized.
A Bigger Cooldown Could Follow
The forecast becomes much less certain beyond the first week of September, although Schuster believes the odds of a notable push of colder air are increasing.
Some computer-model runs have shown a substantial dip in the jet stream developing over the Midwest and eastern United States, which would allow a strong cold front to move south out of Canada. Such a setup could produce another round of severe weather along the front before noticeably cooler air arrives behind it.
Other model runs have shown a very different pattern, including more complicated storm activity along the West Coast while the heat dome remains stronger farther east.
Schuster emphasized that the second week of September is still roughly seven to 10 days away, leaving plenty of time for those projections to change. Even so, he currently leans toward colder-than-normal air becoming more likely somewhere across the northern tier of the country during that period.
For the month as a whole, he said the temperature outlook becomes less decisive. The Climate Prediction Center is showing roughly even chances of above- or below-average temperatures across large parts of the country, while the southern Plains and Southeast have somewhat better odds of finishing warmer than normal.
That creates an interesting September setup because the month may begin with widespread summerlike heat before stronger cold fronts gradually become more common. Instead of a smooth transition into fall, Schuster’s forecast points toward repeated swings between heat and cooler Canadian air.
El Niño Shapes The Tropical Picture
El Niño is also producing very different conditions between the Pacific and Atlantic tropical basins.
Schuster said the Pacific hurricane season is highly active, helped by warmer water and reduced wind shear. Two tropical storms east of Hawaii are expected to strengthen during the coming days, potentially becoming Category 2 and Category 3 hurricanes, while additional areas of possible development are also being monitored.
The Atlantic has been much quieter. Schuster noted that the basin has recorded no hurricanes so far in 2026, raising the possibility of an unusually quiet or even record-setting season if that pattern persists.
Even during an El Niño year, however, he stressed that tropical storms and hurricanes can still form.
One disturbance being watched near the Lesser Antilles consists of the remnants of Tropical Storm Dolly and is expected to move toward Florida and the Bahamas over the next several days. Schuster believes strong wind shear will make redevelopment unlikely, although he said a small chance remains that the system could organize and eventually create concerns around Florida or the Gulf of Mexico.
If it fails to redevelop, he expects the system mainly to produce rain rather than become a significant tropical threat.
Another disturbance near Louisiana has been given roughly a 20 percent chance of development over the next few days. Schuster said it should move generally toward Houston while producing scattered showers and thunderstorms along the Louisiana coastline, without signs of a widespread washout.
September Could Bring Repeated Weather Swings
Schuster expects September to remain busy even if the Atlantic tropics stay quieter than normal.
The first part of the month appears likely to feature a powerful heat dome across much of the central and eastern United States, repeated thunderstorm chances from the northern Plains through the Midwest and Northeast, and cooler, wetter conditions around portions of the West.
The larger question is what happens once stronger cold fronts begin pressing south from Canada. Schuster believes that transition could increase severe-weather opportunities again while eventually bringing more noticeable fall air into northern parts of the country.
After an unusually active August despite relatively little tropical activity, he expects September to continue the unsettled pattern in a different way, with greater chances for cooler air but plenty of heat and storm potential still mixed in.
That combination is what may make September especially interesting: instead of one dominant weather regime, the month could repeatedly shift between lingering summer heat, strong storm systems and the first more meaningful signs of fall.
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.
