Statistics say we’re due for drought
By James D. Ritchie

It’s hard to offer pinpoint forecasts for severe weather trends, but the numbers call for dry.

On the first day of summer, the mercury topped 100 degrees in 40 U.S. cities, from Sacramento, Calif., to Richmond, Va. In the nation’s heartland, for the rest of the season, searing heat ushered in a relentless drought that had people talking about a return to the Dust Bowl days of the 1930s.

That was in 1988, the year of the most recent general drought in the Midwest. Heat waves and rainlessness are nothing new, of course. Some section (or more than one) of the crop belt gets hit virtually every year.

But is another widespread drought in the offing for the Midwest?

“We’re due,” said Elwynn Taylor, atmospheric scientist with the Iowa State University agronomy department. “Looking back at the past 800 years of weather history [viewing such evidence as tree growth rings], there has been a major drought every 18 to 20 years. Our last hard drought was in 1988.”

And some signs are threatening. In July 2006, El Niño conditions came into play. El Niño, you may recall, is the term applied to above-average warming of the surface waters of the Pacific Ocean along the equator. That warming pumps up a terrific amount of energy and moisture, which generally has a positive influence on Midwest crop weather.
El Niños typically last a year to 14 months. But this one was unusually short. Just before Christmas, El Niño petered out and conditions in the equatorial Pacific shifted back into weather neutral. Then, in March, El Niño’s cooler and dryer cousin, La Niña, put in an appearance.

“We’ve never experienced a widespread drought during an El Niño event, but this El Niño didn’t last long,” said Taylor. “And, since we moved toward La Niña so quickly, we could be in for a drought—maybe as severe as in the 1980s.”

Taylor isn’t exactly predicting that kind of harsh summer, but some of the portents are disturbing.

“I watched Arkansas weather through March,” he said. “The wetness or dryness of Arkansas in March is a good indicator of what Corn Belt weather will be at planting time.”

For much of winter (through February) most of Arkansas was wetter than usual. True to form, ample moisture—at times too much—visited the Corn Belt as planting time approached. Along about now, in June, Taylor shifts his attention to the Carolinas.

“I watch South Carolina especially,” he said. “In summer, a high pressure system typically parks in the Atlantic, dominating weather systems. When that Bermuda High is strong and located in the right place, it has a strong influence on the eastern Corn Belt. When South Carolina is dry in June, we can expect dry summer weather in the central and eastern Midwest.”

There aren’t many clues to the rest of the growing season in longer-range outlooks. National Weather Service Climate Prediction Center (CPC) looks for temperatures to be well above normal in the south from now through August, especially in Florida and south Texas. But for the Corn Belt proper, CPC gives even chances for normal temperatures and precipitation. Larry Acker, of 3F Forecasts, Polo, Ill., looks for a hotter-than-normal summer—drier and windier than normal across most of the Corn Belt.

Abnormally dry weather for the rest of the season would cause big hurts. Earlier, corn growers announced intentions to plant 90.5 million acres in 2007, compared with 78.6 million acres last year. That’s a 15 percent bump and most of the increase is borrowed from soybeans and cotton—especially on Dixie acres equipped with irrigation. Not all of those intended acres got planted, but this is still the biggest corn acreage since 1949.

As mentioned, what kind of crop that huge acreage produces remains to be seen. Thanks to technology and better agronomy, the upward trend line on corn yield should see a national average of 148.8 bushels per acre, with a decent growing season.

“If we have a good year, corn yield should average 158 bushels,” said Taylor. “With La Niña back, we may see yields of only 143 bushels or so. Based on 100 years of weather data, the worst we could expect is a 110-bushel average yield. The best: 169 bushels per acre.”

With the volatility in the market now, small weather events can make an out-sized difference in corn prices. Depending on the size of the crop, ethanol will claim 25 to 30 percent of the production. If we have a short crop, livestock feeders, exporters and other corn users will have to bid hard to stay competitive.

“There will be no corn carryover when harvest begins,” said Art Barnaby, ag economist at Kansas State University. “Any production problems will send markets higher. If there is real damage, such as the 130-bushels-per-acre national average yield we saw in 2002, then the market will increase to ration the available supply.”

Even with a good crop, Barnaby expects corn prices to average above $4 per bushel. With a so-so growing season, the price could peg on $5 or higher. “If we get a 1988-style drought, all bets are off,” said the KSU economist.

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