Winter Outlook 15/16

meteomorris

What will be the influence of El Niño?

Synopsis: There is a greater than 90% chance that El Niño will continue through Northern Hemisphere fall 2015, and around an 85% chance it will last through the 2015-16 winter. (source)

The above is a nice begin. For the next few months I'll look forward to winter 15-16. There have recently been plenty meteorological phenomena that made you think. Will it be a strong and cold winter, or just a warm winter with lots of snow in the high alpine?

What is El Niño?
El Niño (Christmas' Child in Spanish) is the name for a phenomenon that takes place off the west coast of South America. Normally, the sea water here is relatively cold (between 16 and 20 °C (winter / summer)), but there are years when the water is warmer. A warming that has consequences for the distribution of air pressure in the world. We see the most striking result on the Pacific Ocean.

Because of the changes in the temperature of the seawater, and the associated wave currents, we see that the pressure distribution in the upper air is changed as well (with a delay of several months). Specifically, this means that more often than usual you'll encounter a low pressure system off the coast of Canada which pushes in warmer air to the continent with a southwesterly flow.

El Niño in full effect

Global impact
But not only do you see the impact in North America. There are consequences on other continents as well.

Impact of El Niño

'Double peak "El Niño; double as hot?
What makes the current event so special is that last winter we had been dealing with a (weak) El Niño and in the western part of North America they are still dealing with the effects of the mild and especially dry winter. After this weak El Niño follows, according to forecasters, a second peak and this might well prove to be the strongest El Niño ever. The strongest El Niño ever recorded dates from 1997 and the events of 2015 could be even more powerful.

Models are showing a strong El Niño

Such a double peak with a strong second peak is uncommon. There is data available only from 1986-1987. And that was a snowy winter in the Northern Alps in Europe.

Will winter 2015-2016 bring lots of snow to the Northern Alps?
It may well do. It is true that since 1986 there has been a lot of changes in the atmosphere, but still. Because there appears to be a link between El Niño and rainfall in northwest Europe. Often we see in the spring an increase in precipitation in the northwest and west of Europe. This is because the effects of El Niño on a global scale have a delay of around 3-6 months before arriving in Europe.

Would that be a possible explanation for the numerous and often lengthy snow fall during the winter of 1986-1987? Is it that the double peak  causes more precipitation in the northwest? Will El Niño bring lots of snow to the Northern Alps? What do you think??

Will we see that much snow?

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