El Nino Returns
Image showing location of warmer than normal ocean surface temperatures during El Nino.
Depending on who you ask El Nino is likely to return or has already begun in the equatorial waters of the Pacific Ocean. Meteorological agencies in the U.S. and Australia believe the onset of El Nino is likely to begin in August or September while their counterpart in Japan says it’s already here.
What is El Nino? For a simple but intense explanation by the late, great Chris Farley CLICK HERE. (*please note the link does not bring you to an explanation that is accurate nor informative). El Nino is a periodic warming of surface waters near the Equator in the eastern Pacific ocean (off the coasts Central and South America) while surface water temps run below normal in the western Pacific near the coast of Australia. La Nina is the complete opposite with cooling in the east and warming in the west. The slight uptick in water temps near North America can greatly influence weather patterns including those for our area. The last El Nino winter was in 2009-2010. The following two winters were taken over by La Nina.
Typically El Nino leads to milder winters with less snow for our region while the west coast and Gulf states experience a cooler, wetter pattern. It’s important to note THIS IS NOT ALWAYS THE CASE but simply the most likely scenario. Last winter, with La Nina in effect we would have expected a colder, snowier winter and got just the opposite. The reason? A positive North Atlantic Oscillation or NAO around the Arctic. This is another periodic pattern influencing our seasonal weather. It is also much tougher to forecast ahead of time. Last winter it became a stronger player over La Nina resulting in a Great Lakes winter that more resembled an El Nino year in terms of temperatures. In fact It’s possible the winter of 2011-2012 could have been even warmer if not for La Nina!
As we head into autumn we’ll know for sure if El Nino is back and have a good idea as to how strong it will be. But whether El Nino is the main contributor giving us mild winter remains to be seen. There are a lot of players on the field when it comes to a seasonal forecast and every now and then one of the typically smaller players can come off the bench and have a big impact putting the all-stars like El Nino in the shadows.
CLICK HERE to check out long term forecasts from NOAA’s Climate Prediction Center.