Ag Weather Forum

Drier Trend in Stages for Summer

Bryce Anderson
By  Bryce Anderson , DTN Senior Ag Meteorologist
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Rainfall for mid-June through mid-July offers decent amounts for the entire Corn Belt, helping to hold off major yield impact from late-season hotter and drier trends. (NOAA graphic by Nick Scalise)

I'm tempted to say, "Well, the time has come" in referring to the onset of the month of June. After all, we have talked and talked about the beginning of the summer season it seems like every day since the first of the year. The conversation has, of course, all related to the Pacific Ocean trending away from the warmer water temperature along the equator, and away from the strongest El Nino in almost 20 years, to cooler conditions in the span of a few weeks, and the start of an equally-robust La Nina event. Along with that ocean change, upper-air patterns across the U.S. have also been promoted as making their own swift alterations, and generating withering hot and dry conditions, and leading to what amount to crop production calamities in this day and age. Some lofty corn price forecasts due to the rapid change have been included in these discussions as well, I might add.

Yes indeed, the time has come. And, the Pacific sea temperatures are definitely cooler. Surface and sub-surface temperatures took a big drop over the past two months. Sub-surface Pacific Ocean water is almost entirely cooler than normal, according to the latest Climate Prediction Center (CPC) Pacific analysis. Also, the barometric pressure feature known as the Southern Oscillation Index (SOI) has retreated from El Nino levels to "neutral" in the past month. This indicates that prevailing west-to-east subtropical jet stream energy will also diminish during the summer.

How does that play out in terms of heat and dryness in the Corn Belt, with the Pacific cooling and the atmosphere wind mechanism undergoing changes? The answer, in our DTN Ag Weather group's opinion, is that, while a drier and warmer to hotter pattern is setting up, it's likely to have a couple identifying features: 1) Arriving in stages; and 2) Not fully setting up shop until the last third to half of the season. This opinion makes sense when you consider that soil moisture is adequate to surplus over much of the central U.S., which helps to moderate the impact of heat development; and that the atmosphere continues to indicate that west-to-east flow will keep bringing upper-air disturbances through the central U.S. several times during at least the balance of June through mid-July. The U.S. Climate Forecast System (CFS) model takes note of that, with an average total rainfall forecast of four to six inches over almost the entire Corn Belt during the mid-June to mid-July time frame. Temperatures also have a variable range, but certainly not excessive heat region-wide.

The farther we get into the last half of summer, though, the greater the likelihood that the trail of storm systems will dwindle. And, that's when we look for the hotter and drier conditions to develop. That's during August. And, if this verifies, we could see some yield reductions in end-of-fill stage corn along with an impact on soybeans during most of their pod-set and pod-fill stages. This is not a crop disaster, but it does have the potential to curb yields at the top end for the 2016 harvest.

Bryce

Twitter @BAndersonDTN

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Bryce Anderson
6/5/2016 | 6:06 PM CDT
For market-related comments, I invite you to participate at the Market Matters, Technically Speaking, or Fundamentally Speaking blogs.
ralph.olson.sons@plantpioneer.com
6/4/2016 | 10:35 PM CDT
Another chance for you to be wrong again ! This why you have been stopped out of your trades