THUNDER BAY — If the coming winter turns out to be gentler than normal in the Thunder Bay area, credit may have to go to El Ninõ.
It's the part of a climate pattern that refers to the unusual warming of surface water in the eastern Pacific Ocean.
According to the US National Oceanic and Atmosheric Administration, El Ninõ is "humming along" in the tropical Pacific, and it is virtually certain it will last through the Northern Hemisphere winter.
NOAA scientists believe the chances of a strong El Ninõ event are 75 to 85 per cent.
Environment Canada senior climatologist David Phillips said the phenomenon often sees warm breezes blowing into the Canadian prairies.
"One of the functions of El Ninõ is that polar vortex, that cold Arctic air pinned well up to the north. Those breezes are blowing from west to east, and the northern air is just sitting up there and not spilling down."
In an interview Wednesday, Phillips said there's no guarantee, but in a strong El Ninõ year, there tend to be fewer days with temperatures below -20 C.
"When we look at winters in the past in Thunder Bay, typically when you have a strong El Ninõ and a large one, then the milder winters are maybe four times more likely than the colder."
He said Canadian and American weather forecasters currently share the expectation this will prove to be the case this winter.
"So you've got two weather services all agreeing on this with different [forecast] models, then it gives you more confidence that this is how it's going to materialize."
Phillips cautioned, though, that "just because you have El Ninõ it doesn't mean it's tank-top kind of weather in January. I'm talking abut a January that may not be as cold as what we've seen."
While winter doesn't officially start until Dec. 21, there have been years when snow covered the ground in Thunder Bay by Halloween.
Phillips noted that the past week or so has been slightly colder than normal in the city, and that there's a chance of flurries Thursday night to Monday, but there will be no "big dump of snow, no hunkering down kind of thing" over the short term at least.
"Thunder Bay has certainly fared better recently than other places in Northwestern Ontario," he said. "Kenora got up to almost 30 centimetres of snow, and Armstrong had about 11 centimetres."
