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FRIDAY, SEPTEMBER 04, 2026   |   SPECIAL REPORT & ANALYSIS

SPECIAL REPORT  |  CROP WEATHER

Heat Dome Tightens Grip, but Plains Rain Signal Emerges

Brutal heat threatens late crops before a potential moisture break arrives ahead of winter wheat planting

Analysis  ·  September 4, 2026

The U.S. weather pattern remains threatening for crops across the southwestern Corn Belt, central and southern Plains and northern Mid-South, where a persistent upper-level ridge is expected to suppress rainfall while maintaining temperatures generally 10 to 15 degrees above normal during the coming week. The most intense heat is now expected Tuesday and Wednesday, when portions of the southwestern Corn Belt and southern Plains could run 15 to more than 20 degrees above normal.

The heat now in force

The heat is already significant. National Weather Service advisories Friday cover portions of Iowa, Nebraska, Kansas, Oklahoma and northern Texas, with projected heat indices reaching 105 degrees across parts of Iowa, Nebraska and Kansas and as high as 109 in Oklahoma and northern Texas.

Table 1. Heat headlines in force Friday morning, Sept. 4, 2026. Source: National Weather Service forecast offices; heat indices as issued.

Figure 1. The ridge and the storm track, Sept. 4-10. Schematic rendering of the forecast temperature departure and rainfall pattern described by NOAA/WPC and CPC guidance; state shading indicates the dominant signal, not a uniform value.

The week-two signal, and how much to trust it

The bigger change in the forecast is farther out. The latest 11-15 day outlook calls for the upper-level ridge to flatten enough to allow above-normal rainfall chances to expand across portions of the Plains and western Corn Belt. NOAA’s Climate Prediction Center similarly favors above-normal precipitation across much of the Rockies and Plains during its Sept. 11-17 outlook, although forecasters stress confidence is below average because models disagree sharply over how much moisture will penetrate beneath the ridge.

That distinction is important: the wetter forecast is encouraging, but it is not yet a high-confidence rain event. CPC rates confidence in both its six-to-10-day and eight-to-14-day forecasts at just 2 on a scale of 5. Models generally lean wet while historical analogs and atmospheric teleconnections point much drier, making rainfall placement and amounts unusually uncertain.

Figure 2. Precipitation lean for Sept. 11-17. Schematic rendering of the NOAA Climate Prediction Center 8-14 day outlook issued Sept. 3, 2026. Forecast confidence: 2 of 5.

Table 2. Week one against week two, by region. Source: NOAA/CPC 6-10 day and 8-14 day prognostic discussions and Week-2 U.S. Hazards Outlook, issued Sept. 3, 2026.

What the heat does to corn and soybeans

For corn and soybeans, the next week is more of a finishing-weather issue than a make-or-break pollination event. Much of the crop is sufficiently advanced that the heat will not carry the same yield threat it would have in July. But extreme temperatures combined with depleted soil moisture can accelerate maturity, shorten late kernel filling in corn and reduce soybean seed size, particularly across Missouri, Kansas, Nebraska and adjoining areas where crops remain less mature or moisture reserves are limited.

That suggests the weather carries some supportive implications for corn and soybean prices, but probably not enough by itself to generate a major weather rally unless the expected week-two rainfall disappears and the hot, dry pattern becomes more persistent.

Table 3. Crop and pasture conditions, week ended Aug. 30, 2026. Source: USDA NASS Crop Progress. Labor Day pushes the next report to Tuesday, Sept. 8.

The winter wheat question

The implications could be more important for winter wheat. Kansas alone planted 6.9 million acres of winter wheat for the 2026 crop, underscoring how important central Plains soil moisture becomes as producers move toward fall seeding. Hot, dry weather through early September will continue pulling moisture from the upper soil profile. A meaningful rain event during the Sept. 11-17 period could therefore arrive at an almost ideal time to recharge seedbeds ahead of hard red winter wheat planting and improve prospects for germination and fall establishment.

CPC’s current outlook is particularly favorable for Kansas, Nebraska, Colorado and the northern Plains, where above-normal precipitation is indicated during Sept. 11-17. Oklahoma and northern Texas are currently closer to near-normal precipitation probabilities, so the southern Plains moisture outlook remains less convincing.

Figure 3. Drought coverage and agricultural area affected. Source: U.S. Drought Monitor, National Drought Mitigation Center; agricultural area shares as reported for the week ended Sept. 1, 2026.

The other side of the divide

Meanwhile, the northern Plains and northern Corn Belt remain on the opposite side of the weather divide. Thunderstorm chances will persist during the next several days, producing generally above-normal rainfall from portions of the Dakotas into Minnesota and nearby areas. CPC continues to favor above-normal precipitation across North Dakota, South Dakota and Minnesota into the extended period.

Bottom line: The immediate agricultural concern remains extreme heat and rapid soil-moisture loss across the southwestern Corn Belt and central and southern Plains. For mature corn, the damage window is narrowing, while soybeans, sorghum, cotton, pastures and livestock remain more exposed. But increasingly, the weather story is shifting toward the potential mid-September pattern change. If the projected Plains rainfall materializes, it would ease crop and pasture stress and, importantly, improve conditions ahead of winter wheat planting. If that rain signal disappears in subsequent forecasts, concerns about Plains dryness could quickly become a more significant wheat-market issue.

Weather & Market Scorecard: Ridge-Locked South, Verified North

Table 4. Weather & Market Scorecard, Friday, Sept. 4, 2026.

Figure 4. Three sessions into September. Source: CME Group settlements as reported by Brownfield Ag News, Sept. 1-3, 2026.

What changed since Thursday

Weather. The National Weather Service escalated the product, and the product is the story. Thursday’s map carried heat advisories; by early Friday NWS Topeka had posted an Extreme Heat Warning for roughly two dozen central, north-central, east-central and northeast Kansas counties running through 7 p.m. Sept. 8, with afternoon heat indices of 100 to 107. NWS Kansas City/Pleasant Hill issued its own Extreme Heat Warning through Sept. 8, and Springfield, Mo., added an advisory through Sept. 6. An advisory says uncomfortable; a warning says dangerous.

Drought. The Sept. 3 Drought Monitor, valid Sept. 1, landed after Thursday’s edition and it is the single biggest data change. Coverage of the lower 48 in D1-D4 drought rose to 59.1% from 56.6%, a third straight weekly increase and 6.4 points in a fortnight. Corn area in drought is 28%, up a point; soybeans 30%, up two; spring wheat 82%, up two; the cattle herd 60%, up two. The South saw widespread expansion in Mississippi, Texas, Oklahoma and Arkansas. The High Plains was the one improving region, with 0.5 to 2 inches from western Nebraska and western Kansas into Colorado and Wyoming.

Outlook. CPC’s Sept. 3 six-to-10 and eight-to-14 day discussions replaced Tuesday’s, valid Sept. 9-13 and Sept. 11-17, with confidence unchanged at 2 of 5 in both. The wet signal reads as more clearly anchored in the West than it did Thursday: above-normal precipitation probabilities exceed 40% from the Pacific Coast into the western Rockies, while the central Plains east to the Atlantic is explicitly flagged as uncertain, with models leaning wet and analogs leaning dry. The Plains rain is still the right thing to watch; it is not yet the thing to trade.

Hazards. The week-2 hazards outlook rolled forward to Sept. 10-16. Extreme heat was stepped down to a slight risk on Sept. 10-11 across the Great Plains, the Mississippi, Ohio and Tennessee valleys and the Southeast, from Tuesday’s moderate risk for Sept. 9. The Rapid Onset Drought area is now described as the central and southern Plains and the middle and lower Mississippi Valley.

Crops. No new condition data. Monday’s Crop Progress remains the newest read and the rows carry it unchanged; Labor Day pushes the next report to Tuesday, Sept. 8.

Markets. Thursday reversed two rows. December Chicago wheat broke 19 3/4 cents to $7.54 1/4, its worst session of the week, and December corn slipped 2 3/4 cents to $5.40 3/4; November soybeans recovered 6 cents to $13.16 1/4. Cattle went the other way and went hard: October live cattle jumped $4.12 to $214.30 and October feeders $6.72 to $321.10 on cheaper feed, a firmer cash market and short covering after an oversold stretch. Choice boxed beef eased $1.48 to $377.30.

Scorecard rows that moved. Cattle and HRW wheat were both re-labeled to say out loud that fundamentals and flat price have separated – forage costs and seedbed deficits are still building while Thursday’s tape went the other way in each. The eastern Corn Belt row was reframed around the new below-normal precipitation lean for the Ohio and Tennessee valleys rather than the retired flood risk. The western Corn Belt row moved from forecast to verification on the High Plains rainfall. Mid-South/Delta narrowed as the Tennessee Valley and Southeast dropped out of the Rapid Onset Drought wording.

AG POLICY & MARKETS DAILY   |   SPECIAL REPORT  |  CROP WEATHER — FRIDAY, SEPTEMBER 04, 2026