Cutoff low, expanding ridge, and strengthening El Niño reshape U.S. crop weather outlook into June, farmers should watch sub-seasonal trends closely as June approaches.
A highly active stretch of weather across key agricultural regions in the United States is signaling a major shift in atmospheric patterns that could influence crop development, drought conditions, and summer forecasts says Eric Snodgrass, Sr. Science Fellow, Nutrien Ag Solutions.
Over the past weekend, storms delivered meaningful rainfall across parts of Florida, Texas, and South Dakota. These accumulations, measured over a 72-hour period, are already helping chip away at persistent drought conditions highlighted in the U.S. Drought Monitor.
With additional precipitation opportunities emerging, this trend may continue to improve soil moisture profiles in critical growing areas says Snodgrass.
At the same time, temperature trends are also shifting quickly. A cooler-than-normal start to May across much of the eastern United States is expected to reverse sharply, particularly across northern regions. This transition will help recover growing degree day (GDD) deficits that have slowed crop development early in the season. Meanwhile, western regions that have experienced warmth will soon cool as a new system moves in.
Big Pattern Change Takes Shape
Snodgrass explained that meteorologists are closely monitoring a developing upper-level cutoff low that is expected to detach from the main jet stream and move into the western United States between May 25 and May 27.
As this system sinks into the Great Basin, it is set to interact with a strengthening ridge of high pressure building across the northern tier of the U.S. and into central Canada.
This evolving setup is significant for agriculture. The cutoff low is expected to enhance the subtropical jet stream, drawing moisture into drier areas of the Western Plains. At the same time, it will increase rainfall potential across the southern United States, providing further opportunity to erode long-standing drought conditions.
There are also indications that this pattern could persist into June. Two dominant high-pressure systems, including the Bermuda High, are suppressing upward motion in the atmosphere and redirecting storm systems southward. This type of blocking pattern mirrors conditions observed during the onset of the 2023 El Niño and raises questions about how long the current configuration will remain in place.
Model Trends and Regional Impacts
Forecast models are beginning to align on several key features for the next two weeks:
The European operational model suggests drier conditions will dominate across the Midwest, Northern Plains, Great Lakes, and the Canadian Prairies.
In contrast, the southern United States is expected to see pockets of heavy rainfall, with totals ranging from 2 to 5 inches in some areas.
A split-flow jet stream pattern is forecast to persist into early June, supported by ridging not only in the central United States but also across the North Atlantic and Western Europe.
Out West, the late-May system will bring strong winds, with gusts of 40 to 60 miles per hour possible across Oregon, northern California, and the Great Basin. These conditions elevate wildfire risk, particularly in areas already experiencing dry fuels.
Temperature extremes are also emerging as a concern. Under the influence of a strong ridge, there is no risk of frost across northern regions. Instead, heat will dominate. Montana has already issued heat advisories and red flag warnings, with temperatures expected to climb into the 90s and near 100° Fahrenheit.
El Niño Signals Strengthen
Large-scale climate indicators are increasingly pointing toward a significant El Niño event developing through the summer.
One of the most critical indicators, the Southern Oscillation Index (SOI), continues to drop sharply. This index measures the pressure difference between Darwin, Australia, and Tahiti and provides insight into trade wind behavior. When the SOI falls below minus seven, it signals a shift toward El Niño conditions. Current trends suggest that threshold is being crossed, reinforcing the likelihood of a robust event.
It is important to understand that El Niño is driven by atmospheric changes first, with ocean temperature anomalies following. The alignment of the SOI, MJO, and wind patterns suggests that one of the stronger El Niño events on record may be developing.
June and July Outlook: A Transition Worth Watching
Sub-seasonal forecast composites tied to negative SOI conditions offer a useful guide for the weeks ahead.
In June, the central United States is expected to trend drier, while the Southwest and Southeast experience increased storm activity. By July, the pattern often shifts, bringing more frequent storms into the central U.S.
Current forecasts appear to match this progression closely, making the transition between June and July especially important for agricultural planning.
Bottom Line for Producers
Seasonal outlooks for June through August remain highly variable and should be interpreted with caution. Instead, Snodgrass suggests the most reliable insights will come from sub-seasonal analysis in two- to three-week windows.
With rapid changes underway, farmers and agribusiness stakeholders should stay attentive to short-term forecasts and evolving climate signals. The weeks ahead will play a critical role in shaping crop outcomes and water availability as the 2026 growing season progresses.
Photo Credit: USDA