Crop season weather outlook mixed
February 13, 2012
Nebraska state climatologist Allen Dutcher recently spoke to alfalfa producers at the Mid-America Alfalfa Expo in Kearney, Neb., about the future of the weather. After some areas of Nebraska dealt with flooding in the spring last year and then drought in the late summer, planning for this year is crucial to producer’s success.
Dutcher began the seminar by explaining the weather conditions over the globe, and how what happened last year that caused the drought is looking to repeat itself.
“When the [Pacific ocean] water is warmer than normal, you tend to see more evaporation. When the water is colder than normal, you tend to see less evaporation. That has an influence on the jet stream that impacts our weather,” said Dutcher. “We are in a La Nina event now, which is what caused the extreme drought in the South.”
He continued, “When you have warmer than normal conditions, which is called an El Nino event, you typically have an enhanced Southern jet stream. That is that jet stream that comes in to the southern third of the United States. Under those conditions, we tend to see above normal precipitation, and below normal temperatures for the Southern third of the U.S. and we tend to see above normal temperatures and below normal precipitation for the upper third of the U.S. In between lies Nebraska, and we can go either way.”
Right now, the La Nina event is looking to go into it’s second year. “Typically when we see these La Nina events materialize, about 50 percent of the time those go into a second year. Here is the crucial part going forward in terms of a forecast. Of those that make it into a second year, 50 percent of those make it into a third year,” said Dutcher.
If this happens, the South will continue to face drought, although it will not be to the extreme that it was last year. If La Nina does not continue, the process will flip flop.
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“However, if they don’t go into another year, they revert to an El Nino. We have never seen neutral sea surface conditions the following fall and that is very, very important if it holds true because that will be suggestive that if we go into an El Nino, the Southern U.S. is going to have a pretty significant chance of getting some good precipitation going into next fall,” said Dutcher.
He added, “For Nebraska, the one thing we do see with the El Nino and La Nina is the fall. La Nina usually gives us a dry, warm fall, which is good for harvest. With El Nino we tend to see above normal precipitation, and we tend to see some harvest activity delays.”
According to Dutcher, the models are neutral right now, and it will be hard to predict exactly what is going to happen moving into the spring. “The average is right at the neutral line over 18 models across the globe. However, here is the important fact to understand with this: this is the weakest time of the year for these models to perform,” he said.
Part of the problem in Nebraska right now is the lack of winter precipitation. This precipitation is very important to soil moisture recharge, which is the amount of moisture in the soil itself.
“We have seen negligible soil moisture recharge, and unfortunately the precipitation patterns that we have had have missed those key areas. We need that soil moisture to carry us through the dry times. If you have decent soil moisture, which we don’t, you can make it through the dry times,” he said.
Dutcher explained that from the beginning of October through the end of April, 70 percent of the moisture that falls will actually get into the soil moisture profile. As of now, Nebraska has only seen 25-50 percent of the normal precipitation to this point, and that has led to little soil moisture recharge.
“It was found that you need 12-inches of precipitation for dryland corn producers from October through April to get the right amount of soil moisture recharge. For every inch that you are short, you will see a 2.5 percent reduction in production compared to your baseline yield trend. If we get normal precipitation from this point forward, we will be looking at a 7.5-12.5 percent reduction in yield. If the same pattern that we have established continues, we will increase our projected yield reduction to 12.5-17.5 percent yield reduction. That is why we are concerned, and why we might see a drought alert in April,” said Dutcher.
This soil moisture recharge will not affect irrigated fields as much, but a lot of farmers in Nebraska due a dryland system, and the lack of soil moisture could pose problems later in the summer.
Adding to the worry is the little snowpack that the Rocky Mountains have seen. “We have a very poor snowpack, and we need to see it stabilize or improve going forward. If you can keep the distance between when the snowpack disappears and the monsoon begins to a bare minimum, you can survive the dry periods. If not, it can be nearly impossible to keep crops alive,” he said.
He added, “For dryland producers, this is a very scary situation as we go forward.”
The dryness in the Northern Corn Belt will continue to be an issue for producers in that area. “I do not see any alleviation of this dryness, at least in the near future. All our numerical models show this,” said Dutcher.
In the Eastern Corn Belt, there is too much moisture. “The Eastern Corn Belt moisture has been significant, and I do expect that we will see some planting delays again this year,” he said.
The South is not expected to have as significant of a drought this year, but the precipitation needed to recover the area is unlikely to happen, according to Dutcher.
As of Feb. 7, the majority of the state of Texas is still under an extreme or exception drought, with nearly all of the state being in some state of drought. Oklahoma, New Mexico, and Southern Kansas are in the moderate to extreme category of drought. In the South Eastern part of the U.S., Georgia is suffering from exception drought as well, and the surrounding states are also in drought.
Southern Colorado, Arizona, Utah, Nevada, California, Oregon and Washington have severe to moderate droughts, as does Iowa and Minnesota. North Eastern Nebraska is classified as abnormally dry.
“Am I saying there is going to be a drought in Nebraska? No. But the odds are not looking very promising in some portions of the state to not be in drought. It is going to be crucial for producers in the North Eastern part of the state to see normal precipitation for March and April, to have any chance of escaping drought,” Dutcher said.