La Niña Watch issued: The impact on Central Texas

  

AUSTIN (KXAN) — As the world continues to deal with an incredibly strong El Niño, the climate scientists at the Climate Prediction Center are now forecasting a quick return to La Niña later this year.

El Niño is the warm phase of the El Niño-Southern Oscillation pattern, characterized by warmer than normal sea-surface temperatures in the equatorial Pacific Ocean. La Niña, conversely, is the cold phase with cooler-than-normal water temperatures.

CPC issued a La Niña Watch to give a proactive heads-up of the likelihood of a return to La Niña. According to NOAA, a La Niña Watch is issued when “Conditions are favorable for the development of La Niña conditions within the next six months.”

La Niña Watch
La Niña Watch

How quickly will we make the transition?

El Niño, and the positive effects we’ve enjoyed this winter, will still be here a little while longer. The latest ENSO forecast from the CPC suggest we’ll still be in El Niño through the March-May period. NOTE: ENSO forecast phases are broken down in 3-month overlapping periods.

After that, we then enter a phase of ENSO, affectionately called ‘La Nada,’ which means ENSO in Neutral and doesn’t have a meaningful impact on the weather. We should be in ENSO Neutral beginning April-June and continuing through May-July.

A return to La Niña is favored to begin in the June-August period with increasing odds of La Niña through the fall.

La Niña impacts to Central Texas

Typically La Niña isn’t what most people in Central Texas want. Generally speaking, it means winter will be warmer and drier than normal. A drier winter can often set us up for more drought and a hotter summer, but not always.

Typical La Nina impact on the U.S. in winter (NOAA)
Typical La Nina impact on the U.S. in winter (NOAA)

Bear in mind that the CPC ENSO forecast does not yet stretch into next winter, but it seems plausible that La Niña in late fall will continue into winter too.

How has El Niño treated us?

Our expected ‘wetter-than-normal’ winter did indeed materialize. Since the start of meteorological winter on Dec. 1 we’ve had 9.48″ of rain, which is more than two inches wetter than a typical winter and slightly wetter than a typical El Niño winter.

Winter rain in Austin (Camp Mabry)
Winter rain in Austin (Camp Mabry)

Typically during El Niño winters the storm track is through the southern states, and that typically leads to more opportunities for storms and beneficial rain.

El Niño pattern
El Niño pattern

When will confidence increase?

There’s a phenomenon in ENSO forecasting known as the “Spring predictability barrier,” which alludes to the fact that forecasting the phase of ENSO for the following winter can be a challenge until you get past spring.

This means that confidence in what to expect next winter will go up as we near the beginning of summer.