El Nino declining, cool sister may take its place
A temperature shift in the tropical Pacific Ocean, combined with climate model outlooks, suggest that it probably is.
In fact, if surface sea waters continue to cool, La Nina could emerge as early as this fall, say scientists with the National Oceanic and Atmospheric Administration and an increasing number of international forecasters.
Why is this significant?
Because La Nina – like its attention-grabbing brother El Nino – can disrupt normal weather patterns around the globe. But while El Nino is marked by a band of warmer-than-average seawater in the equatorial Pacific, La Nina represents cooler-than-average water in the same region.
Which means, if El Nino seesaws into a La Nina event, various parts of the world could get hit with very different weather in 2016-17.
The Pacific Northwest is no exception. In 2015, El Nino was a major driver behind the region’s unusually warm weather and lack of snowpack in the mountains. The emergence of a strong La Nina could do just the opposite, bringing greater precipitation and cooler temperatures.
It’s not unusual for these naturally occurring phenomena to run back to back. Most legendary is the double billing that took place in the late 1990s, when the strongest El Nino on record segued into a powerful La Nina. Each ushered in its own stretch of intense weather conditions around the globe, ranging from heat waves and severe droughts to heavy rains and flooding. If El Nino produced intense heat and less-than-average rain in a certain location, chances are La Nina did the reverse.
Talk about the ultimate sibling rivalry.
If a La Nina episode is on the way, its impact in the U.S. would peak next winter, bringing cold and wet weather to the Pacific Northwest, warm and dry conditions across the southern states and cold, stormy weather patterns to the central and northern tier.
Nic Loyd is a meteorologist with WSU’s AgWeatherNet. Linda Weiford is a WSU news writer and weather geek. Contact: linda.weiford@wsu.edu