El Niño Year

Unofficial Networks recently posted the prediction on whether we would experience an El Niño year or a La Niña year. The prediction is that there is a 70% chance of El Niño conditions this January, February, and March. However, it is also predicted that it is going to be a weak El Niño.

But what does an El Niño snow season mean…?

In an El Niño a low pressure system is present, which causes the Southern Rockies as well as Sierra Nevada mountain ranges to experience snowfall that is greater than average. The upper midwest and the north-east regions experience below normal snow conditions. So, yes, technically this snow season should be good for all of us in the western region, but as we all know, weather can be unpredictable.

The reason behind why scientists believe it will be an El Niño year can be a bit hard to understand. Scientists are able to reference data from years prior to analyze the weather and temperature patterns in order to make their predictions. One of the variables they use in order to predict future weather patterns is sea surface temperature. For example, going back to December of 2004, when the West Coast experienced a weak El Niño we also saw that there were sea surface temperature anomalies in the central Pacific. This anomaly in the central Pacific usually signifies that there will be a weak El Niño season. On the contrary, when we experience these same anomalies in the eastern tropical Pacific we usually get a strong El Niño. Of course there are always exceptions to this trend such as last season which was classified as a “coastal El Niño”.

These anomalies are associated with the South Pacific Oscillation.

This South Pacific Oscillation is a key observation in predicting whether the west coast will experience a weak or strong El Niño year. If there is a strongly positive South Pacific Oscillation then there will likely be a strong El Niño, whereas if there is a neutral or negative South Pacific Oscillation there will likely be a weak El Niño. A positive South Pacific Oscillation means that the west Pacific becomes cooler while the eastern ocean warms. On the other hand a negative phase means that the west Pacific becomes warmer while the eastern oceans cool.  Using just this information scientists are able to predict the strength of an El Niño about 75% of the time…pretty cool!

So this year when scientists and analysts looked at the South Pacific Oscillation charts they found that the pattern appeared negative. This means that there is a negative South Pacific Oscillation and hence most likely a weak El Niño for the winter to come.

The connection between the South Pacific and weather patterns is amazing. Everything in nature is interconnected. We are skiing in the cold on snow that was affected by the wind and temperature changes in the oceanic and tropical regions!


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