Dakota Beacon

The La Niña of winter and spring 2021 brought drought to the northern plains. Very little winter snow fell. Likewise, scant spring rain. This poses a substantial fire danger. With pasture grass scarce for cattle and crop planting delayed, agriculture takes a hit. The southern plains, on the other hand, experienced a reasonably moist winter continuing into spring 2021. All this thanks to La Niña.

A weather pattern called the El Niño - La Niña cycle, also known as the El Niño Southern Oscillation (ENSO), was well known for hundreds of years. This weather pattern begins in the Pacific off the coast of South America. La Niña means “Little Girl” and occurs as the opposite or reverse weather pattern of the El Niño. El Niño means “Christ Child” so named because the seasonal pattern begins around Christmas.

During April 2021 the tropical Pacific Ocean reverted to an ENSO-neutral condition as the coupling between the atmosphere and ocean weakened. Forecasters concur with the La Niña-neutral modeling through the summer 2021 in the northern hemisphere. Then the hedging begins as the conditions mitigate trending once again toward El Niño conditions. Most likely, though, the probability of La Niña remains around 50-55% through late fall and early winter.

This situation differs significantly from the 2019 flooding in the plains states brought on by El Niño. Conditions were so severe that much of the acreage in the plains states remained unplanted.

“Global warming! Climate Change!” cry the Chicken Littles on the left. “The sky is falling!”

Not so fast. Hundreds of years before the industrial revolution South American fishermen recognized the fluctuation of warm and cool waters along the coast of Peru and Ecuador. The pattern remains. Not until the 1920s did a British meteorologist, Sir Gilbert Walker, identify and record the fluctuations. He theorized that the association between water temperatures and atmospheric conditions created cyclical weather patterns leading him to conclude what he dubbed the ENSO.

A subset of the ENSO weather pattern is the Madden-Julian Oscillation (MJO). Whereas the ENSO may vary over a year or more with a complete oscillation taking 3 to 5 years, the MJO is a major fluctuation of tropical weather on a weekly to monthly timeline. It is an eastward moving pulse of clouds and rainfall near the equator caused by the jet stream.

ENSO signals cooler than normal temperatures in the eastern Pacific Ocean and warmer temperatures in the western ocean. It is believed that ENSO results from the increased strength of the normal trade wind circulation. Typically, the trade winds drive warm Pacific surface water westward to the regions of Indonesia and Australia. This movement permits cooler water to well up along the South American coast. Why these winds increase in strength is not completely understood. The amount of cooler Pacific water moving toward South America reduces the air temperature and generates winds along the coast.

The further result of the oscillation of the cooler water moving to the South American coast and the warm water to the west increases the high cloud buildup in southeast Asia producing wetter than normal conditions over Indonesia and Australia during the northern hemisphere’s winter.

Focusing attention on the northern hemisphere pinpoints the crux of the matter for the US. Changes in the tropical Pacific both in water temperature and in the trade wind circulation induces wide fluctuations in the jet stream in the middle latitudes. These fluctuations of the jet stream crossing the United States from west to east determines rainfall patterns. Such a shift in the jet stream results in a wide variation in the strength and location of storms. In other words, radical changes in the atmosphere and jet stream cause radical variations in temperature and precipitation across North America. These changes can last for several months.

Looking back over the years, forecasts of the ENSO predicted harsh winters and spring floods. News stories in the winter and spring of 2019 foretold weather extremes to come. Severe storms for the plains and higher temperatures for the southeast sparked flooding in some areas and drought and wildfires others. The central plains saw more storms, precipitation, and flooding.

The National Oceanic and Atmospheric Administration (NOAA) constantly monitors the ENSO and MJO attempting to forecast their impact on the US. Currently, the ENSO forecasted La Niña will continue its impact through the summer and maybe even into early winter.

So much for the prognosticators’ claim of manmade climate change. These oscillations have been causing severe weather for centuries. To believe manmade climate change was responsible for the current spate of severe weather just isn’t so. The scientific meteorological explanation of ENSO and MJO makes much more sense.

On a lighter and more distracting note, consider “Summer Shower” by Emily Dickinson.

“A drop fell on the Apple Tree, Another on the Roof;

A Half a Dozen kissed the Eaves, And made the Gables laugh-

A few went out to help the Brook, That went to help the Sea;

Myself conjectured were they Pearls-, What Necklaces could be…”

I wonder what Ms. Dickinson would think of La Niña and El Niño? Her poet’s heart probably could care less, I’m sure.

Dennis M. Patrick can be contacted at (JavaScript must be enabled to view this email address).