Threat of new Southwest drought lingers with La Nina

Brian Bledsoe, chief meteorologist and climatologist for KKTV in Colorado Springs, Colorado, told those in attendance at the Texas A&M Beef Cattle Short Course on Aug. 21 it’s not his intention to haunt the dreams of producers by mentioning 2011, even if climate and ocean temperature patterns appear to be leading to another dry spell in coming years.

David Cooper

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“Everybody’s always asking, ‘When’s 2011 going to happen? Are we going to have another 2011?’” Bledsoe said, referring to the historic year when cattlemen throughout the Southwest were forced to sell off much of their herds due to drought.

“Let’s be real about this, OK? 2011 was the worst one-year drought that Texas has ever had on record. So will Texas have another severe drought here in the future? Absolutely. Unequivocally. Without question. The problem is figuring out when that’s going to happen.”

Bledsoe said the biggest indicator for severe drought patterns is usually how the Pacific Ocean measures water temperature. Warm concentration of Pacific Ocean temperatures over the past year has allowed an El Nino trend to develop. Warm Pacific waters usually lead to higher moisture and some cooling through the Southwest, Southern Plains and Midwest.

Those patterns are beginning to flip, Bledsoe said, noting a “huge difference” in the end zone atop the west coast of South America. “Water has gone from 3 degrees Celsius above normal to, in some cases, 3 degrees below normal. Six degrees, that is a huge difference in terms of atmospheric energy and global positioning of weather patterns.”

But Bledsoe said the pattern flip won’t happen suddenly. Much of the Pacific as a whole remains warmer than average, which means the warm state will remain and allow time for La Nina to develop. La Nina patterns are cooler ocean waters in the Pacific basin, usually sending warmer temperatures and less precipitation through the South and Midwest regions.

As the whole Pacific starts to cool off with a Pacific oscillation, “it causes drought in parts of the midwestern high plains and southward,” Bledsoe explained.

Bledsoe added that his own charting of temperatures since 2005 and additional weather pattern studies going back to the ’30s show generally that cooling periods of the Pacific oscillation can last up to 25 years or longer. Those periods include short “detours” of oceanic warming – much like what was seen from 2014 to 2016, which was some of the warmest Pacific temperatures recorded on the index.

“However, I really do believe this period of time here is nothing more than a short detour in a longer term pattern on the Pacific deep cold. This Pacific just keeps getting more cold lately. It could full-on flip in phases.”

Bledsoe told those in attendance that knowing how severe another drought could be for the Southwest is relative to knowing how long.

“The odds are Texas is going to have a severe drought, and I’m talking about multi-year. Am I certain? No. Am I confident in my estimation? Yes.

“[Producers] need to have their stuff together when we go from [moisture] to [drought]. And what I mean by having it together is having your drought plan perfect. When it’s wet, that’s the time when you get your drought plan together.”

That preparation period could be extensive, Bledsoe reminded the audience. La Nina weather patterns don’t develop instantaneously, he said, and the weather patterns show a weaker La Nina developing into “nothing terribly strong” to start.

“The Pacific is still crazy warm. Until that Pacific pattern cools down, a really long-lasting La Nina cannot gather strength and hold and have an impact. [But] even a weak La Nina is not favorable to this southern interior of the country.”

History says when the Pacific flips back, it is usually followed up with a longer lasting La Nina episode, Bledsoe said, “and that could cause some problems.”

“As much advanced warning on something like that is something important. So make sure you’re prepared. While you have seen 2011, you have not seen the ’30s or the ’50s. You did not see parts of the 1800s. Those times featured multi-year drought, extreme drought in some cases. I’m not saying we have to prepare for that tomorrow. But if you’re under 40, and you’re in this business, you’d better have some preparation.”