It’s flanked by wind anomalies, as surface level winds rush toward the area of storminess. The MJO is an area of storminess that travels west-to-east along the equator. This warm subsurface will provide a source of warmer water to the surface over the next couple of months and helps provide confidence in the forecast.įurther bolstering the chance for El Niño is a short-term forecast for the Madden-Julian Oscillation (MJO). NOAA animation, based on data from NOAA's Climate Prediction Center. Water temperatures in the top 300 meters (1,000 feet) of the tropical Pacific Ocean compared to the 1991–2020 average in February–April 2023. After many months cooler than average, the amount of warmer subsurface water has increased over the past month as a downwelling Kelvin wave-an area of warmer water that sloshes from the west to the east beneath the surface-traverses the tropical Pacific. We always keep an eye on the temperature of the water under the surface of the tropical Pacific. For some examples, here’re Niño-3.4 forecasts from the European multi-model ensemble, Australia’s ACCESS-S2, and the North American Multi-Model Ensemble.īut it’s not just model advice supporting the forecast. When there is a lot of agreement among the models, we tend to give more credence to their predictions. What’s behind this?įirst, the latest runs from our computer climate models are providing very high probabilities that El Niño will develop this year. ENSO tends to change phase during the spring, and the tropical Pacific ocean-atmosphere system can be more susceptible to smaller pushes like short-term weather variations, contributing to the “ spring predictability barrier.” So it seems the forecasters are really feeling their oats this month, to be giving El Niño such relatively high odds. Forecasts made during the spring are often less accurate than those made other times of the year. I’ll get back to the potential impacts of El Niño in a minute-first, let’s discuss this confident forecast. ![]() There is a lot of variety, and no prediction is ever perfect! But it’s currently the best tool we have to anticipate upcoming seasonal conditions. Since ENSO can be predicted months in advance, we can start playing the odds on what sort of climate patterns can be expected. When El Niño or La Niña are holding court in the tropical Pacific, they can affect global temperature and rain/snow patterns in specific ways, with the strongest impacts during the winter. We spend a lot of time and effort monitoring and predicting ENSO because it can give us an idea about upcoming potential weather and climate conditions (and because it is a fascinating natural system!). Blue bars show the chances of La Niña, gray bars the chances for neutral, and red bars the chances for El Niño. NOAA Climate Prediction Center forecast for each of the three possible ENSO categories for the next 8 overlapping 3-month seasons. That’s where we are… but where are we going? There’s a 62% chance that El Niño will develop during the May–July period, and more than 80% chance of El Niño by the fall. Near-zero, like the current values, tells us that the atmospheric patterns are near average over the tropical Pacific Ocean. Negative index values indicate the Walker circulation is weaker than average, an El Niño response, while positive values tells us the west-east pressure difference is greater than average, indicating a strengthened Walker circulation-a La Niña response. ![]() Both of these indexes measure the strength of the atmospheric component of ENSO, via the relative surface pressures in the western and central-eastern Pacific. In March, both the Southern Oscillation Index and the Equatorial Southern Oscillation Index were close to zero. The atmosphere is also looking quite neutral, overall. Graph by Emily Becker based on monthly Niño-3.4 index data from CPC using ERSSTv5. Of all the previous 7 events, 2 went on to La Niña in their third year (below the blue dashed line), 2 went on to be at or near El Niño levels (above the red dashed line) and three were neutral. ![]() Three-year history of sea surface temperatures in the Niño-3.4 region of the tropical Pacific for the 8 existing multi-year La Niña events (gray lines) and the current event (purple line).
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