This morning I picked my first bouquet of daffodil blooms. Though not especially noteworthy, it is unusual because the timing is early — way early. In the Ozarks, old-timers sometimes called daffodils “Easter lilies,” but it has been a long time since they bloomed that late in the spring. But blooming closer to Valentine’s Day than Easter is a sure sign that things are changing.
That bloom time has sped up should not be too surprising because 2023 was the hottest year on record and predictions are that the coming year will be more of the same. A graph showing average sea surface temperature throughout the year over the past 40 years looks like strands of spaghetti stretched across the page, but the line for 2023 stood apart and well above the earlier tangle of lines. The 2023 line was about one degree Fahrenheit above the 40-year average. Air temperature averages mirrored the ocean temperature record.
This is an El Nino year, so unusual weather conditions are to be expected. Officially called El Nino–Southern Oscillation, this well-known weather event has been known officially since the late 19thcentury but only studied intensely since the 1960s. The Southern Oscillation is part of a cyclical weather pattern that repeats itself every two to seven years, with five years being the average. El Nino and La Nina are the names given to describe the warm and cold surface sea temperatures while the Southern Oscillation is the name used to describe the effect oceanic temperatures have on air temperature and worldwide weather patterns.
The neutral phase of the Southern Oscillation represents average conditions prevailing between the Indian Ocean (western Pacific between Australia and Indonesia) and the eastern Pacific (equatorial South America, centered more or less off of Peru). In the neutral state, the temperature differential between sea surface temperature in the western Pacific is about 15 degrees Fahrenheit warmer than the water off of Peru. In this neutral state, rainfall patterns are predictable and timely.
The El Nino phase occurs when warmer than normal surface water forms off the coast of South America and trails westward along the equator. Normally these conditions last 9 to 12 months, but can go on for two years. The lack of a strong sea temperature differential between the western and eastern Pacific slows (and sometimes reverses) the trade winds that normally blow from east to west along the equator resulting in droughts in southern Asia, parts of Africa and India. Heavy flooding often occurs in equatorial South America during El Nino years. El Nino years generally result in more precipitation across most of North America, including the southeast, and sometimes more severe springtime storms. In California more rainfall in the south is common during the winter, but the relationship is not always clear-cut.
La Nina is a reversal of conditions when the difference in surface water temperatures decreases, resulting in colder than average temperatures off of South America and somewhat warmer conditions in the Indian Ocean. Usually, this means drier than normal conditions across most of the country with the upper Midwest experiencing more winter snow but hotter, drier summers. The spring storm season is usually pushed further north in La Nina years.
How climate change and the El Nino-Southern Oscillation cycle interact is still up for debate. Most expect that the generally warmer climatic conditions will make the strength of the El Nino events stronger – at least in the near future – until ocean temperatures warm everywhere and reduce the temperature differential. Early indications are that the frequency of El Nino events and their relative strength has increased in the past 20 years, but not enough data points are available to answer that question definitively.
Sitting here a month before the first day of spring, I know it is too early for it to be so warm. I also know that winter has not yet made its last stand. Hopefully, that stand will occur in the next few weeks, not delay until April, when a hard freeze does so much more damage.
