Iowa State University Extension climatologist Elwynn Taylor spent three days at the 2012 Farm Progress Show answering farmers' questions about the weather. The show was August 28-30 at Boone in central Iowa. It was a hot three days—temperatures reaching the high 90s. What was the most common question?
"Farmers asked a lot of questions, but none were desperate questions," says Taylor. "Most farmers have crop insurance and that will likely get them through the 2012 drought situation. They may not make money if they don't have a crop to sell, but crop prices are high and hopefully those farmers who are hit hardest by the 2012 drought will be able to cover expenses and get through."
The big question: Is this the end of the drought of 2012? Or will it stretch into next year? "I gave six scheduled talks to audiences, two per day at the show. At the end of all six of my presentations, that question was asked right away," says Taylor. He also visited with numerous individual farmers streaming through the ISU exhibits in the university's hoop building.
It'll be quite a challenge to fully recharge subsoil moisture
So what is the answer? "We don't know for sure if the end of the 2012 growing season is going to be the end of the drought," says Taylor. "But we do know it's going to be a big challenge to recharge all of the reserve moisture to the subsoil. Not just the moisture that was used up during the 2012 drought year but the moisture reserve that was used last year, too."
Hopefully, the weather between now and next spring will be slightly to the wet side of usual to replenish soil moisture for the 2013 crop. "But we're not counting on that," he says.
This 2012 drought really began last year. The rains stopped around the first of July 2011 over much of the Corn Belt, so the crop did suffer a bit in 2011. Subsoil moisture was reduced already a year ago between July and harvest time. And the subsoil moisture supply didn't recover over the past winter as we had a dry fall and dry winter. We're still very low on subsoil moisture supply in Iowa and the Midwest. The tank of reserve soil moisture, so to speak, is either very low or is still pretty dry in a wide area of the Corn Belt.
For clues to what kind of weather Iowa and the Corn Belt will likely have in 2013, you need to keep an eye on La Nina, says Taylor. A continuing La Nina weather pattern means more drought ahead. But if the pattern switches and an El Nino phase develops, weather conditions will favor a return to normal rainfall, normal temperatures and good yields.
Keep an eye on La Nina/El Nino situation for clues to 2013 yield prospects
Recently some weather analysts have said perhaps La Nina is showing signs of weakening and a return to El Nino conditions is coming. That would favor good yields in 2013. During the Farm Progress Show there was a report from one private weather research firm indicating concern that El Nino is weakening which would mean continued dry weather. The question is, did we ever get into a full-fledged El Nino in 2012? And if so, is it now weakening?
"We didn't reach the real classification or criteria of El Nino," says Taylor. "Some weather analysts believed they saw an El Nino coming and made some assumptions. So you may have heard in the news that an El Nino was established. But this weather pattern or event has not officially made it to El Nino strength yet. It just got close and seems to be languishing at the present level trying to make up its mind whether it's an El Nino or a La Nina."
And yes indeed, over the past two weeks or so, there are two or three definite signs of some weakening and that the situation is now moving back towards a La Nina, adds Taylor. With an El Nino the temperature of the water on the surface of the ocean off the west coast of South America (near the equator) is warmer than usual. "But what's happening now is there are some flaws in the consistency of the ocean temperature being warmer than usual off the west coast of South America," he says. "There are a few cooler spots appearing in the water now."
Scientific indicators signal that an El Nino hasn't yet returned
The atmospheric pressure associated with El Nino and La Nina is the real indicator or measure of how these two possible occurrences (La Nina or El Nino) are going to be influencing the weather. "We as climatologists and weather scientists set a value historically for the atmospheric pressure differences (it's called the Southern Oscillation Index or the SOI) and it has not yet reached its value to be classified as El Nino," says Taylor. "The SOI has just gotten close to that level previously, but it is now drifting away from that level at the present time."
Does this situation increase the odds that Iowa and the rest of the Corn Belt could return to a La Nina pattern? Would that increase the possibility we could have similar weather in the coming winter, spring and summer of 2013 as we had in 2012?
"Let's just say it makes it possible we could have similar weather," says Taylor. "We can't put odds on it. We don't have any data historically on such an occurrence. So setting odds isn't really possible to do with any real certainty, but just to see this happening tells us the possibility of a continuation of drier than normal weather has to be considered."
Possibility of drier-than-normal weather stretching into 2013 must be considered
The 2012 drought year has been compared to the 1988 drought. It's also been compared to the mid-1950s. What are Taylor's thoughts on that? He says 2012 is comparable to droughts in the mid-1950s and to the mid-1970s and to 1988. "And all of these droughts are comparable for the same reason," he adds.
A strong La Nina got the drought going in 2012. So did a La Nina event in the 1950s. "The 1950s was the strongest measured La Nina since climatologists have been keeping records, which is about 120 years," says Taylor. "This La Nina we've just experienced in 2012 is the second strongest one compared to the one in the 1950s. The 1950s La Nina was stronger and it went on for about three years and caused a great deal of concern. However, both of these La Nina events, 2012 and mid-1950s, are similar in nature. And both of them are in the same locations; the 1950s drought occurred in similar areas as what we are seeing this year."
Farmers have better hybrids today, and better corn growing techniques
"We have two sets of numbers," Taylor answers. "One of our yield estimates is based on the data that says this is not only the first major drought since 1988, but it's of equivalent strength. Going with the equivalent strength analysis, most forecasts we're seeing are based on the 2012 drought being nearly identical to the 1988 drought. But we have better corn hybrids today and better management for growing corn. So if 2012 is just like 1988, my calculation is the yield this year would be 121 bushels per acre. USDA's first official estimate of the 2012 corn crop, which USDA released in its August Crop Report, was 123.4 bushels per acre. That will be updated by USDA in its September Crop Report to be released September 12."
Various groups are trying to come up with a number for the U.S. yield average for corn this year. A well-known private forecaster last week released an estimate of just over 120 bushels per acre for the average yield of the nation's corn crop in 2012. What does Taylor think? Does he have a number?