La Niña Set to Fade Away in the Coming Months

By Matt Makens Atmospheric Scientist

La Niña conditions continue to fade, which will mean a pattern change coming our way through the year. This subject is critical to our industry, as we have seen the negative impact of La Niña grow during the past few years. By no means do I mean to imply that getting rid of La Niña will fix everything, but for the majority, it will be better for beef and agriculture if its influence is gone. Problem is, El Niño can spread drought across the northern states, so there is not a win-win for everyone.

Putting this latest La Niña episode (three winters in a row now) in the rearview mirror will mean improving drought conditions, a more favorable growing season and regenerating soil health. How long it takes to tackle all those obstacles remains to be seen, but we will be on our way.

The latest forecast for La Niña takes that pattern down to only a 14% probability of existence this spring and down further to a 10% likelihood by the summer. What takes its place is the next question, and for a time, we will be sitting in a neutral phase, which means neither La Niña nor El Niño controls us. That neutral phase may last several months before allowing a chance for El Niño to gain traction through the summer into the fall and next winter.

El Niño’s probability of developing by summer is 39% likely but climbs to more than 50% likelihood by the fall. Here is a look at that forecast; the chart below shows the odds (percentage chance) of having one of the three phases in place during the months ahead. For example, the tallest gray bar is in March-April-May and is the highest probability of a neutral pattern. Still, red bars (El Niño’s forecast odds) increase to be the highest of the three by August-September-October.

A quick explanation, the Pacific Ocean from South America toward Southeast Asia will fluctuate between colder and warmer than normal surface water. This impacts how storms develop over those parts of the ocean, which causes changes globally in how the weather pattern is positioned.

To be cooler than average, the sea surface is in La Niña which promotes drought for North America. If that ocean warms above average, called El Niño, it promotes storminess for much of the country.

Granted, as is always the case with weather, we shall see. Let us assume, however, that we have either neutral or El Niño conditions in place for the second half of the year. How might that look in terms of precipitation? Here is a comparison between those two patterns for the summer and the fall. The green areas show historically wet regions, and oranges indicate drier than normal spots.

Spring Outlook by Region

Northwest: Even if La Niña has weakened, there will be residual impacts to the region. This will favor some periods of precipitation and mountain snows. Precipitation, in most cases, will be enough to break even for the season. Temperatures will remain cooler than average for the season.

West: The wetness of winter will subside. Similar years of the past and model projections indicate near normal to slightly drier than average conditions for March through May, however, the surplus from winter will carry over to benefit the start to growing season. Temperatures will be closest to average for the north, but southern areas will see warmth take over.

Southwest: Drier than average conditions will cover most of the region, particularly over New Mexico. Soil moisture will continue to be an issue on the Plains to start the growing season. The northwestern mountains of Colorado and the Wasatch Range in Utah will continue to receive snowpack albeit near average. Temperatures will warm above average for the season, as much as one to two degrees warmer than normal for New Mexico, southern Colorado and eastern Arizona.

Northern Rockies: Hit and miss moisture for the mountains and plains. The probabilities of above versus below average precipitation are equal. Areas with snowpack will likely see that melt and runoff before soils thaw enough to absorb much of that moisture. Temperatures will be coolest to the west and north. February through March hold on to chances for sharp drops in temperatures. Yet, with a rapid warmup in April and May the season will average out to near normal temperatures overall.

South: Western areas will continue to fight against poor soil conditions as odds favor a drier than normal forecast here. Toward the east, however, east Texas, Arkansas, Louisiana and Mississippi have better odds of a wet pattern. A warm outlook, like last year, with temperatures several degrees warmer than average for the period.

Upper Midwest: Like the Northern Rockies/ Plains, moisture will be hit and miss. The spring likely ends near normal for the region’s precipitation. And snowpack will be mostly runoff for the Mississippi versus soils until we thaw. Near-normal temperatures for the season following some cold snaps in March.

Between those comparisons for summer and fall, you can see how adding El Niño (bottom images) can dramatically change the outlook. In both cases, it is better historically than leaving La Niña and her widespread drought patterns in place.

Although I believe we transition out of La Niña, I question the speed at which we see dramatic pattern changes around the country. I wrote a lot about how a drawnout transition would look in the previous issue of the National Cattlemen. For now, it is best to consider the neutral phases as the best forecast guidance for the summer. Slow or not, a transition from La Niña will lead to several things. Among them: The chances for hail and wind outbreaks drop when we are no longer in a La Niña phase. The risk of hurricanes also decreases as El Niño increases its strength. Additionally, we will have better chances to recover water levels for the Colorado River Basin and the Mississippi River. So, there will be plenty of changes to watch during the year.

Ohio Valley: A favored area for precipitation to the benefit of the start to growing season and runoff for the Mississippi. The highest probability country-wide for moisture sits smack dab on this region. With the moisture comes nearly normal temperatures throughout, trending warmer than average for the south as the season progresses.

Southeast: Producers to the north and west in this region will fair the best with spring moisture, others will tend to be normal to drier than normal and the driest conditions spread across Georgia and Florida. Warmer than normal temperatures expected for the spring, warmest to the west and south.

Northeast: Moisture near the Great Lakes will continue to be more than normal, with the rest of the region in neutral chances for wet versus dry. Temperatures should break even on the season.