Photographer: Gregory Boissy/AFP via Getty Images

A Weak La Nina Finally Arrives After Confounding Forecasters

  • The weather-changing event could fall apart by winter’s end
  • U.S. gas, coal in Australia may gain on La Nina weather

Bets that a Pacific Ocean La Nina will boost natural gas prices in the U.S. and coal prices in Australia may be about to pay off now that forecasters have determined that the weather-changing event is here.

After months of conflicting data that left meteorologists around the world divided and traders searching for clues, the U.S. Climate Prediction Center Thursday said that a weak La Nina is underway. It has the potential to bring the coldest U.S. winter since the “polar vortex” that sent gas prices surging across the U.S. in 2014, and rains that can flood coal mines in Indonesia and Australia, curbing supplies.

Still, this La Nina is weak and probably won’t last more than a few months, U.S. forecasters said. The Australian Bureau of Meteorology, which uses different criteria for declaring a La Nina, earlier this week said it didn’t find one underway. Japan said a La Nina was here in September.

“There needs to be some caution here because our probabilities are not that high as you get into the winter,” said Michelle L’Heureux, a forecaster with the center in College Park, Maryland. “There is some chance here that it will fall apart.”

About half of all U.S. households use gas for heating, and consumers may spend 22 percent more for the fuel this winter compared with a year ago, U.S. Energy Information Administration data show. While forecasts for unseasonably warm weather through most of November have bloated gas stockpiles, a La Nina-inspired chill during December, January and February could have a significant impact on prices, said Teri Viswanath, managing director for natural gas at PIRA Energy Group.

Conflicting Forecasts

“Cold weather for these three key weather months, that changes the trend in prices for 2017,” Viswanath said.

In June, the El Nino that had dominated the world’s weather for more than a year ended and forecasters and traders began to anticipate the arrival of La Nina. Since then conflicting forecasts have sewn confusion in markets.

Private forecaster The Weather Company on Oct. 24 said November through January will bring above-normal temperatures across all of the U.S. with the exception of the Southeast. The official U.S. forecast calls for Maine and much of the southern U.S. to be warmer than normal, while colder-than-normal temperatures will take hold in upper Great Plains and western Great Lakes.

Thursday’s update should provide some clarity.

La Ninas occur when the Pacific’s surface cools to at least a 0.5 of a degree Celsius (0.9 Fahrenheit) below normal and the atmosphere has a reaction. They can disrupt weather around the world bringing dryness to southern Brazil and to the U.S. South, as well as heavy rain across Australia.

L’Heureux said La Nina conditions were found in the basin through last month and the agency believes they will persist. For the U.S. to declare a La Nina, the ocean cooling must last five consecutive three-month periods.

“There is some chance here that our retrospective will say that it won’t qualify,” L’Herureux said. “It is such a weak, marginal event.”

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