CHICAGO, ILLINOIS — A very wet stretch of weather is lining up for the center of the country next week, with the NOAA 6-10 Day Precipitation Outlook, issued September 23, 2026, showing a 50 to 60 percent chance of above-normal precipitation from Minnesota and Wisconsin south through Iowa, Illinois, Missouri, Arkansas, Louisiana, Mississippi, and East Texas.
The outlook is valid from September 29 through October 3, 2026, and forecasters say Tuesday through Thursday is the main window for repeated rounds of showers and thunderstorms across northern Illinois.
50 to 60 Percent Above-Normal Rain Odds Center on the Mississippi Valley
The strongest wet signal on the map runs in a wide band down the Mississippi Valley, stretching from the Upper Midwest all the way to the Gulf Coast. This darker green zone falls in the “Likely Above” category, meaning rainfall totals are favored to come in above what is typical for this time of year.
Cities sitting inside or near this corridor include:
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Chicago, Rockford (Illinois)
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Des Moines (Iowa)
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Minneapolis (Minnesota)
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Milwaukee (Wisconsin)
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St. Louis (Missouri)
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Little Rock (Arkansas)
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Memphis (Tennessee)
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Jackson (Mississippi)
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Shreveport (Louisiana)
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Houston (Texas)
For residents in these areas, the end of September and the first days of October look noticeably more unsettled than usual.
Tuesday Through Thursday: Repeated Storms Target Northern Illinois
Local forecasters covering northern Illinois highlighted Tuesday, September 29 through Thursday, October 1 as the focus period for multiple rounds of showers and thunderstorms. Rather than one quick system, the setup points to several waves of rain moving across the same areas over consecutive days.
Some of these storms could produce very heavy rain. When downpours repeat over the same neighborhoods, even moderate rainfall can quickly add up and overwhelm drainage systems, especially in urban parts of the Chicago metro.
Flooding Concerns Rise, While Severe Weather Stays Off the Table
Forecasters noted the heavy rain could produce more flooding across the area. The word “more” matters here, since it signals that ground conditions and waterways may already be dealing with recent rainfall.
Most vulnerable areas include:
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Low-lying roads
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Viaducts and underpasses
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Small creeks
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Poorly drained areas
Rivers and streams across northern Illinois and neighboring states will also be worth watching as the week goes on.
On the positive side, there is no severe weather risk at this time. That means damaging winds, large hail, and tornadoes are not currently expected with this pattern. The main concern remains heavy rain and flooding, though forecasts can shift as the event gets closer.
Wider Wet Signal Covers the Plains, Great Lakes, and East Coast
The wet pattern is not limited to the Mississippi Valley. Lighter shades of green, showing 33 to 50 percent odds of above-normal precipitation, cover much of the Great Plains, including:
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Kansas
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Nebraska
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Oklahoma
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The Dakotas
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Most of Texas
To the east, the Ohio Valley, Great Lakes, Southeast, Mid-Atlantic, and Northeast also lean toward a wetter-than-normal stretch. States such as Michigan, Indiana, Ohio, Kentucky, Tennessee, Alabama, Georgia, Florida, Pennsylvania, New York, and New England all fall within the above-normal zone, though with lower confidence than the central corridor.
Drier-Than-Normal Pattern Expected Over Idaho, Utah, and the Interior West
The picture flips out West. A “Below Normal” zone, with 33 to 50 percent odds of drier-than-normal conditions, sits over Idaho, Utah, and parts of Wyoming, Montana, and Nevada.
Much of California, Nevada, Oregon, and the northern Rockies falls into the near-normal category, while the coastal Pacific Northwest, including western Washington, leans above normal for precipitation.
Alaska and Hawaii Outlook
Alaska:
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Western part: Near-normal precipitation
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Southern and southeastern Alaska: Above-normal
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Aleutian Islands: Mix of near-normal and above-normal conditions
Hawaii:
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Favored for above-normal precipitation across the entire island chain during the same period
What Residents in the Wet Zone Should Do Now
With several days of lead time, residents across northern Illinois and the wider central U.S. have a chance to prepare before the rain arrives.
Home Preparation:
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Clear gutters, downspouts, and storm drains near your home
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Check sump pumps and consider a battery backup if your basement is prone to water
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Keep an eye on local forecasts for any Flood Watches or Flash Flood Warnings once the event is closer
Driver Safety:
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Remember: Just a few inches of moving water can sweep a vehicle off the road
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Never drive through flooded roadways
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Plan extra travel time during heavy downpours midweek
Agricultural Planning:
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Farmers wrapping up fall harvest in Iowa, Illinois, Minnesota, and Missouri may want to plan around the wet stretch
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Repeated rain could slow fieldwork and delay harvest operations
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Monitor soil moisture levels and adjust equipment schedules accordingly
General Preparedness:
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Have a weather radio or smartphone alerts enabled
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Know your evacuation routes if you live in flood-prone areas
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Keep emergency supplies accessible, including flashlights and batteries
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Avoid camping or outdoor activities in low-lying areas during the peak rain days
The takeaway: If you’re in the Mississippi Valley corridor from Chicago to Houston, next week looks wet. Prepare now, stay informed, and don’t underestimate the flooding potential when multiple rounds of rain hit the same areas over consecutive days.
