By Rob Paola
If you’re wondering what caused such an abnormally warm month, it has a lot to do with this year’s El Nino, the strongest recorded since 1997 and one of the top 3 strongest in the past century.
El Nino refers to an abnormal warming of ocean currents in the eastern Pacific along the equator. This can have a dramatic impact on weather patterns over North America, usually resulting in a northward shift of the jet stream across Canada. The net result is that during strong El Ninos, any southward push of Arctic air masses are effectively blocked, minimizing intrusions of cold and snowy weather into southern Ontario. Other weather currents can add or subtract from El Nino’s influence.
This year’s very strong El Nino meant an unusually sustained period of this pattern, resulting in a prolonged period of abnormal and sometime record warmth right through December. (Here in Welland, a record of +4.6 was set in December 2015, eclipsing the previous record, +2.9, established in 2006).
There are signs that this pattern will relax in January, with an increased likelihood of colder air from the Arctic making its way into southern Ontario on occasion, along with an increased chance of snow. That’s not to say January will completely flip to a cold and snowy month. but it will likely see more typical winter weather than December did. And that’s probably OK for people who are eager to see some snow in Niagara!
(Rob Paola, a “Welland boy” as the saying goes, is with Environment Canada and currently works at the Prairie and Arctic Storm Prediction Center in Winnipeg, Manitoba as a supervisor and severe weather meteorologist.)