The La Niña phenomenon that has fueled flooding, drought, and other weather extremes is set to stick around for a third winter but could fade away as early as this upcoming Spring. The National Oceanographic and Atmospheric Administration says there is a 71% chance the status will switch to neutral status sometime between February and April.
For those not familiar, La Niña is a climate pattern that describes the cooling of surface-ocean waters along the tropical west coast of South America. La Niña is considered to be the counterpart to El Niño, which is characterized by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean. Together, La Niña and El Niño are the “cold” (La Niña) and “warm” (El Niño) phases of the El Nino-Southern Oscillation (ENSO).
The local effects on weather caused by La Niña (“little girl” in Spanish) are generally the opposite of those associated with El Niño (“little boy” in Spanish). La Niña years are typically characterized by stronger hurricane seasons in the Atlantic, drought conditions in the Southern US, and cold, rainy winters in the Pacific Northwest. El Niño is usually associated with the opposite: warm and dry weather in the northern US, and extra rain to the south. ENSO-neutral patterns are neither. They are characterized by a return to the long-term average.
La Niña has been in place off and on since 2020 and for it to remain in place for three consecutive Winters is extremely rare, having only been recorded two other times. The long duration of the pattern has been blamed for the intensifying drought in the Western and Southwestern US, so an end to the pattern should bring some relief.
La Niña is not expected to switch to neutral early enough to impact this winter. The NOAA is predicting the northern tier of the country to be colder and possibly snowier than normal, while the South sees warmer-than-normal temperatures, which is typical of La Niña winters.
The switch to neutral is expected around the same time we begin the transition from Winter to Spring. As the atmosphere transitions out of a La Niña and tries to head towards an El Niño – the neutral phase – the weather ingredients tend to be less prime for continuous severe weather outbreaks.
The Spring months of March, April, and May are typically the busiest period in the US for severe weather. The good news is that neutral-ENSO conditions tend to produce tornado and hail events that are more in line to slightly less-severe than historical averages.
Meteorologists will then be monitoring ENSO conditions for a transition to El Niño, though it is far too early to predict when that might happen. In general, El Niño-related temperature and precipitation impacts across the United States occur during the cold half of the year (October through March). The phenomenon usually brings wetter-than-average conditions along the Gulf Coast from Texas to Florida, and sometimes Southern California. Elsewhere over the United States, El Niño impacts are associated with drier conditions in the Ohio Valley, and to a lesser extent, the Pacific Northwest and the northern Rockies. (Sources: NOAA, Fox Weather)
