La Nina is likely to persist through the winter, though you wouldn’t know it if you lived in Houston.
The weather phenomenon that has historically delivered warmer winters across the southern U.S. is being challenged by another force known as the Madden Julian Oscillation, a pulse of clouds and rain that moves through tropical oceans. The oscillation is pushing cold air into the south, and temperatures in Houston are well below average.
La Nina can shift weather patterns globally, moving the price of commodities such as coal, soybeans and natural gas. Strong La Ninas have brought flooding rains to Australian coal mining regions, droughts to Brazil’s soybean growing areas and, when the Madden-Julian Oscillation isn’t putting its thumb on the scales, warmer, drier conditions across the U.S. South.
The oscillation has been in just the right places this winter to “help push cold into the U.S.,” said Michelle L’Heureux, a forecaster with the U.S. Climate Prediction Center in College Park, Maryland. “It’s really been a slow mover through these phases as of late, so this has definitely lasted longer than I thought. Hopefully we will see a big warm up coming up here, but it’s certainly taken its time.”
Early December brought record snowfalls and frigid temperatures across the U.S. South, probably the result of the pattern. The low in Houston Saturday is expected to fall to 31 degrees Fahrenheit (minus -0.6 Celsius), 12 below average.
The odds of La Nina, characterized by unusually cold ocean temperatures in the Pacific, lasting through March, are 85 percent, the U.S. Climate Prediction Center said Thursday, little changed from 82 percent a month ago. The phenomenon has contributed to volatile weather.