La Nina Is Still With Us In Fall Of 2011

La Nina Is Still With Us In Fall Of 2011

ISU's Elwynn Taylor is concerned about dryness continuing into next spring and possible drought in 2012. Many Midwest fields need rain to recharge subsoil moisture reserves either this fall or next spring.

Much of Iowa and other areas of the Midwest are dry this fall. Subsoil moisture supplies need to be recharged for the 2012 crop. The best time for that to happen is for rains to come this fall prior to freeze up. Or perhaps these dry areas can pick up some moisture from rains that soak in after the ground thaws next spring. What about drought next year? What are the odds of that happening? With the La Nina weather pattern that is still with us, the possibility of dry weather continuing into the 2012 crop season has Iowa State University Extension climatologist Elwynn Taylor a little worried.

Parts of Southeast Iowa had been listed officially by NOAA (the U.S. National Weather Service) as drought areas during the 2011 growing season, he points out. And they are still quite dry this fall. "What we know today is that the southeast portion of Iowa, and I'm talking about one-fourth of the state, really took it on the chin this past spring and summer in terms of adverse weather," says Taylor. "It was way too wet starting in the spring and then it got way too hot and dry for a long period of time later on during the 2011 growing season."

The government weather service or NOAA looks at determining drought on a county by county basis. "And yes, indeed if you look at drought county by county, southeast Iowa is still not out of the drought yet," says Taylor. "Even though they've had a couple of recent rains in southeast Iowa, they still have not replenished their subsoil moisture. Some corn and soybean yields turned out alright in southeast Iowa in 2011, in areas and fields where they had good, deep-rooted plants that could reach down deep to get the subsoil moisture. But for the most part the corn and soybeans took a beating in southeast Iowa in 2011, and southeast Iowa is now set up for dry weather to occur going into 2012."

Southeast Iowa could have another dry year, unless it starts raining

What about the rest of  the Upper Midwest? Reports are drought conditions are expanding in areas outside of Iowa too. "On the national drought monitor, the most recent edition came out last week, showing a very dry strip running from Canada all the way down to the Gulf of Mexico, and this strip of dry territory is classified as drought," says Taylor. "It goes right down just west of the Great Lakes all way to the Gulf Coast of the U.S. This drought is connected to the drought going on in Texas, Louisiana and the Mississippi River area."

Looking at the Canada to Gulf of Mexico drought strip, at least as far as soil moisture goes, it's not an official agricultural drought yet because of the time of year that it has hit. But it certainly is a harbinger of things that could come in 2012 as for as weather and crop production is concerned—if it doesn't rain.

Are you talking drought? Are we at risk for drought in Iowa in 2012?

"Yes, that's what it looks like now," says Taylor. "What we are seeing is an increase in the amount of risk going into 2012. When we have a dry fall like this, we say Happy New Year on October 1 as far as the hydrologic year or "water year" is concerned. You assume crops are no longer using a significant amount of water after October 1 because they are finished growing and are waiting to be harvested or have already been harvested, and precipitation we get after October 1 is contributing to the soil moisture reserve and going toward the next year's crop. Thus, when we get only a scant amount of rain in the fall, it contributes to increased risk for the coming crop year. Right now, we're getting an increased risk of being short of water in 2012."

It's been awhile since growers in the Corn Belt were talking about going into spring with the possibility of depleted subsoil moisture. "That's right," observes Taylor. "People have pretty much forgotten about this particular kind of dryness as a possibility. Essentially people only remember 3 or 4 years back and for the past several years we haven't even needed to analyze the soil to see how much moisture is in it in the fall because the soil had all the water it could hold over most of the Corn Belt. But this year it is a very different situation. It's quite dry!"

Is La Nina playing a role in the prediction of dry weather for 2012?

"We are still in the La Nina phase that we were in a year ago. Earlier this year the La Nina event did weaken a little, just as it did in previous years when we were in very strong La Nina events," explains Taylor. "And then this current La Nina re-strengthened, just as the La Ninas did in the previous 3 or 4 strongest La Nina events which have occurred during the last 110 years or so of recorded weather records."

Of the four strongest La Nina's ever, the current one we are now experiencing is in second place on the all-time La Nina list. "This La Nina is in second place right now," says Taylor, "and it has done all the same things as those other strong La Ninas did before. They've re-strengthened and we assume this current one will continue to re-strengthen as the other three did in years past. And, if the current La Nina continues into this coming winter, that possibility could be a disaster for crop production in Argentina and southern Brazil because when it is winter here in the U.S., that is their growing season down there in South America."

Taylor adds, "We don't know when the current La Nina will be over for us, but if this dryness continues come next spring, it could do irreparable damage to crops here in the Midwest in 2012. That's what happened in1988, although La Nina was not a direct cause of that drought. But still we had a very early, dry spring which allowed early planting, followed by serious continued drought and high temperatures to start the 1988 growing season. Even though the weather returned to more normal conditions in July and August of 1988, it was too late to produce good crop yields that year."

December 1 is key date for next update on La Nina, says ISU's Taylor

When can farmers expect a more definitive answer or prediction on what kind of spring 2012 weather we will have in Iowa and the Midwest in 2012? "It could turn out like the weather we had when we went into the 2011 growing season," he notes. "Usually we'll have a better idea about this on December 1."

That's why traditionally over the years, Taylor has put together a crop outlook (a weather outlook and his own guess with the help of ISU Extension economists on the supply and demand for corn and beans) around December 1. He will do that again this fall. "Of course, we'll know more when we see what is happening going into March and April of 2012," says Taylor. "But around December 1 is really the next time we get a good look at the weather prospects for the coming year. At that point, we're really getting into wintertime and we can see what the moisture pattern is likely going to be over the winter."

Also, he says you should keep in mind that we don't add much moisture from rainfall into a soil's reserve moisture supply in the Upper Midwest after the soils are frozen in winter. "So it doesn't matter how much snow or how much rain you get, if the soil is frozen. It doesn't soak in," notes Taylor. "The snow melts and water runs off the field if the ground is frozen."

For weather updates: You can follow Elwynn Taylor's latest weather observations and commentary by Googling "Where's Elwynn?" on the Web. On Twitter, you can follow him at twitter.com/ElwynnTaylor.  To follow the drought monitor, go to droughtmonitor.unl.edu/. This U.S. drought monitor map and commentary are kept current, as they are periodically updated by the NOAA.

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