Ag Weather Forum

Pump The Brakes On La Nina Talk

Bryce Anderson
By  Bryce Anderson , DTN Senior Ag Meteorologist
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Pacific Ocean temperatures indicate a struggle to develop even weak La Nina conditions during the rest of this fall season. (NOAA graphic by Nick Scalise)

You've likely seen some comment about how NOAA is predicting La Nina to form in the Pacific. There has also been at least one commodity advisory service predicting a drought next summer (2017 crop year) because of La Nina. Well -- apologies for sounding harsh -- but right now such comments are much ado about nothing and amount to what may be called "weather trash talk."

The reason I say that is this: NOAA has for a long time -- certainly for the past several months -- called for La Nina conditions to possibly be in effect this fall 2016, but then for neutral conditions in the Pacific Ocean to take over as soon as late February 2017. We are seeing that now with the sea surface temperatures. There has been no big-time cooling of conditions relative to normal as would be expected when even a moderate La Nina is forming. Central equatorial Pacific temperatures are running around a half degree Celsius to one degree C below normal (around two degrees Fahrenheit). But in the eastern equatorial Pacific, there's still plenty of water where temperatures are holding at normal values. Significant cooling of the ocean is just not happening.

The Pacific temperatures continue to act along the lines of 1998, which was another crop year following a strong El Nino -- like we had in 2016 (which got prominent mention in DTN programs at the spring and summer farm shows). Here's how NOAA research scientist Klaus Wolter described the situation in an analysis piece October 8:

"The overall evolution of the 2015-16 El Nino was most similar to 1997-98, as monitored by the MEI (Multivariate ENSO Index), except that the latter had already transitioned to weak La Nina conditions by September 1998."

Forecasts at this point continue to suggest that the Pacific is not going to drop off the edge into a rip-roaring La Nina over the next year.

The barometric pressure component of El Nino or La Nina -- the Southern Oscillation Index (SOI) -- is showing the same so-so tendency when it comes to La Nina. The SOI was in a weak La Nina phase on the 30-day moving average during the past several weeks, and the 90-day moving average had also edged into the weak La Nina category (+8.0 or higher). However, as of Friday October 14, both the 30-day and 90-day averages were back in the +7.7 range -- and into neutral category.

What's the bottom line in all this lingo? It's this -- if La Nina's presence continues to be of minor development, the chances for dryness in Argentina and southern Brazil row-crop areas are lower -- and, conversely, the chances for these two regions of South America to have normal growing-season weather conditions are higher. That means a more-promising scenario for corn and soybean production.

As for the U.S., well, there is a long ways yet before the 2017 growing season gets going. But to say that La Nina is going to dry things up is a call that, right now, warrants a healthy dose of skepticism.

Bryce Anderson can be reached at Bryce.anderson@dtn.com

Follow him on Twitter @BAndersonDTN

(CZ)

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