El Nino expected to halt historic rise in Great Lakes

El Nino, the weather-skewing, climate-changing phenomenon that originates in the Pacific Ocean, will likely bring a historic water level rise of the Great Lakes to an end in 2016.

After more than a dozen years of below-average water levels, 2014 and 2015 produced an unprecedented rapid rise in the lakes back to near or at average levels. This year’s El Nino, which some forecasters predict could be the strongest in 50 years, should halt the rise in the next six months, according to a forecast released Thursday.

In addition, El Nino is expected to affect the amount of snow and rainfall Michigan experiences in the next six months. Experts with the National Oceanic and Atmospheric Administration and U.S. Army Corps of Engineers discussed the looming impacts of the phenomenon in a Thursday conference call with reporters.

El Nino is expected to produce warmer temperatures during the winter months than in previous years. But don’t put away the parkas just yet.

“I do want to stress that this does not preclude shorter periods of colder winter weather,” said Jim Noel, hydrologist with NOAA’s National Weather Service Ohio River Forecast Center. “However, the chance of a repeat of a cold winter like the last two years is fairly low ... because of El Nino.”

Frigid winters during the past two years have resulted in 92.5 percent of the Great Lakes being covered by ice in 2013-14 and 88.8 percent in 2014-15 — far above average.

NOAA describes El Nino as a “periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific.”

Along with higher temperatures across the Great Lakes, Noel said the region will see less snowfall.

“One thing we are fairly confident in is the snowfall this winter will likely be not as much as we’ve seen the last two years,” he said.

At this time of year, the lakes are in the midst of a seasonal decline as levels drop from the highs of late summer. The fall is typically driven by the arrival of colder air. When spring rolls around, a seasonal rise occurs for the swimming/boating season.

But temperatures this fall will remain warmer than usual, opening a new set of possibilities.

“One potential impact would be a lower seasonal decline (from) lower evaporation because the water temperature and air temperature differential isn’t (as large) as it typically is,” said Keith Kompoltowicz, chief of hydrology at the U.S. Army Corps of Engineers’ Detroit District. “We also will likely see a lower seasonal rise come spring time.”

Kompoltowicz said those patterns are expected to result in:

■Lake Superior, Lake Michigan and Lake Huron remaining above their long-term averages during the next six months, but fall below levels registered in 2015.

■Lake Erie staying above its historical average in the next six months and remaining above last year’s levels as well.

■Lake Ontario staying at, or slightly below, its long-term average through the next six months and consistently being at or above last year’s levels.

■Lake St. Clair remaining well above its long-term average in the next six months and well above last year’s levels as well.

JLynch@detroitnews.com

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