SLUGGISH LA NIÑA PATTERN FOR WINTER 2024-2025
By Matt Makens Atmospheric Scientist
Through November , La Niña conditions struggled to develop . Ocean temperatures in the El Niño Southern Oscillation ( ENSO ) region of the Pacific ranged between 0.2 to 0.5 ° C cooler than average . For La Niña ( El Niño ), ocean surface temperatures need to be at least 0.5 ° C colder ( warmer ) than average for a sustained period . While temperatures briefly dipped to the La Niña threshold in October and November , they did not remain there long enough to establish a definitive La Niña pattern as of this writing .
Based on current ocean and atmospheric conditions , the scenario for winter into spring of 2025 is a pattern bouncing between a neutral and weak La Niña phase . History and computer modeling have a high level of confidence ( more than 85 %) in this outcome . A stronger La Niña event remains unlikely , with only an 11 % chance of one developing . This indicates drought growth will continue although , perhaps , not as robustly as in a strong La Niña .
Ocean conditions have been in this lasting neutral pattern for months following El Niño last winter , and drought has markedly increased during this time . The summer started with the lowest drought footprint in several years , but historically dry weather has grown across the country this fall . Total cattle , hay and alfalfa areas exceeded 60 % in drought this fall , whereas the acreage was less than 10 % in June . This all occurred without a La Niña in place .
Image 1 visualizes the difference between neutral , weak and strong La Niña events ; clearly , there are differences based on strength . Between the neutral and weak La Niña images , note the similarities in drier-than-average conditions across the South and Plains , meanwhile hit and miss moisture for northern states . These images are averages based on historical conditions since 1950 . It would take a strong La Niña event to deliver lots of water to the areas of the North , which again , is unlikely this time .
Like the ocean surface temperatures , the atmosphere has not fully aligned a strong pattern either . A shift towards a La Niñalike atmospheric pattern occurred between August and early September , leading to rapid warming and drying across much of the U . S . However , from October into November , the atmospheric La Niña signal weakened , allowing for a return of moisture and significant weather events , including historic snowfall in parts of Colorado and northern New Mexico and drought relief across the Central U . S . — notably in Oklahoma .
Of Oklahoma , 42 % was considered in extreme drought at the end of October , but after some rainy days that number dropped to 0 % the following week ( 42 % of the state did , however , remain in severe drought despite that moisture — a sign of how dry summer and fall had been here ). That was a brief reprieve within this overall drier-than-normal pattern expected for the entire cold season .
The neutral-to-weak La Niña condition pattern is expected to persist into early 2025 . While strengthening is possible — like the 2005 La Niña , which did not fully develop until November / December — the overall likelihood is low based on historical trends and computer projections .
This is as expected and continues the same trend as laid out in the outlooks from previous National Cattlemen and the Fall Directions magazine . The analog years that added the most
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