NOAA places El Niño development and persistence through February 2027 at nearly 100 per cent, with sea surface temperatures in the Niño 3.4 region already running approximately 2°C above average, Nutrien meteorologist Eric Snodgrass said on July 13, 2026.

That mounting tropical signal now sits atop an immediate threat: a powerful heat ridge anchored over the central United States that tied or broke all-time temperature records over the weekend and pushed excessive heat watches from the northern Four Corners region through Idaho, Wyoming and Montana and into the Northeast.

"The ridge is the main story," Snodgrass said, referring to an unusually strong upper-level high-pressure system parked over the Upper Midwest.

How serious is the flash drought risk?

Snodgrass projects a large "dry donut hole" will persist across the middle of the United States for the next two weeks, with the western Corn Belt taking the driest conditions.

Precipitation will fall below normal at exactly the wrong moment, as corn and soybeans enter their critical reproductive growth stages.

NASA soil-moisture projections show the combination of persistent heat and reduced rainfall could rapidly deplete available moisture supplies across the western Corn Belt and Northern Plains.

Flash droughts compress what would normally be months of crop stress into weeks. Corn and soybeans become particularly vulnerable when heat coincides with declining soil reserves.

Where does corn yield potential stand today?

Des Moines has already accumulated stress degree days roughly 20 units above normal through early July, according to Snodgrass.

Additional extremes could push corn closer to the yield-loss thresholds that agronomists track historically across the Midwest.

Warm nights may matter as much as hot days. Snodgrass flagged overnight temperatures above 74°F (23°C) as the threshold farmers should watch, because crops lose their recovery window when lows stay elevated after sunset.

"If this forecast fails and the heat stays anchored over the Midwest and Northern Plains, expect rapidly declining crop conditions and more significant yield-loss risk," he warned.

Computer models show the hottest air gradually shifting northwest later in July, with some easing possible between July 20 and July 27. Considerable uncertainty remains.

What is happening outside the heat dome?

Storm systems will continue tracking the perimeter of the ridge, in the so-called "ring of fire" pattern that brings active weather to the Canadian Prairies, Great Lakes, Ohio Valley, Appalachians and Mid-Atlantic.

Snodgrass noted history shows these systems occasionally bend southward from Canada and drop unexpected moisture into the ridge's interior.

The Southwest monsoon remains active and could extend farther west than normal, while beneficial rainfall over the past week has lifted moisture conditions across drought-affected areas of the Southeast and Mid-Atlantic.

A weak tropical low may form along the Gulf Coast early next week. No hurricane development is expected, but the system could generate heavy rainfall from the Gulf Coast into the southeastern United States.

Meanwhile, large wildfires along the Ontario-Minnesota border and across Ontario and Quebec continue degrading air quality across Canada and the northern United States.

Past-week flooding hit eastern Tennessee and scattered areas across Missouri, southern Illinois and Kentucky.

How strong could this El Niño get?

NOAA's near-100 per cent probability runs through February 2027, and Snodgrass said current measurements are approaching levels historically tied to "Super El Niño" events.

Global atmospheric indicators suggest the current heat ridge could weaken and retreat westward later this month as atmospheric momentum declines. He cautioned, however, that weather patterns occasionally stay locked in place longer than expected.

What should farmers watch next?

The decisive variable over the next two weeks is whether storm systems can punch into the heat dome and restore soil moisture before crop stress compounds.

Producers should monitor overnight lows, weekly rainfall totals, and the July 20-27 model shift for the first signals of either meaningful relief or escalating drought pressure across the western Corn Belt.