An El Niño occurrence does not fully guarantee a wet winter. An El Niño can be a failure, but the probability increases for wetter-than-normal weather.

About a dozen moderate El Niño events have occurred in the U.S. since 1950.

“Three of the last four moderate El Niño’s have been whoppers,” Brown noted.

The 2004-2005 El Niño pattern was so strong that Arizona cotton growers could not meet the mandatory plow down date which forced some to file for extensions.

Brown says the moderate 2006-2007 El Niño winter was a “bit of a dud but was back loaded.” Heavy precipitation in January delayed the pecan harvests in Arizona and New Mexico.

Brown believes this winter’s El Niño could resemble the back-loaded 2006-2007 event. “If I was a cotton farmer, I would not procrastinate in bringing in the crop given the recent El Niño history. This fall and winter are trending toward the wet side,” Brown said.

Growers also should expect cooler winter temperatures if El Niño conditions develop this winter. More precipitation leads to more cloudy days and higher evaporation rates which result in cooler temperatures.

Brown also addressed the prolonged drought issue in the West and Southwest. While part of the drought is tied to dry La Niña events, Brown also pointed to “Pacific Decadal Oscillation (PDO).”

This phenomenon refers to a longer-term fluctuation in the water temperature in the Pacific Ocean. Warm and cool phases relate to temperatures off the northern Pacific Coast of the U.S.

When PDO is in a cool phase, it suppresses precipitation in the U.S., particularly in the West which results in drought. A warm phase increases precipitation.

Climate experts know less about PDO than El Niño-La Niña weather patterns. 

“Some climate experts believe PDO could be partially responsible for our longer trends of lower precipitation,” Brown said. “Wet years can occur during the dry cycles, but overall the trend is on the dry side. This may have implications on why we’re in this prolonged drought.”

If this is accurate, Brown says the West and Southwest are about halfway through the current PDO cycle.

cblake@farmpress.com