Milder than normal winters in western, northwestern and central Canada expected due to El Nio: Environment Canada

The current El Niño phenomenon is expected to reach its maximum during the winter of 2015-16, which has historically manifested itself through milder than normal winters in western, northwestern and central Canada, Environment Canada said.

The current El Niño could even be in the “top 3,” according to Columbia University’s International Research Institute for Climate and Society.

Information developed by Environment Canada scientists for the 2015/2016 event said that historically Canada is mostly affected in North Hemispheric winter and spring during El Niño episodes. While milder than normal winters and springs are registered in western, northwestern and central Canada, “a similar, but weaker” tendency is registered over eastern Canada and the Maritimes, the information said. “Generally, El Niño does not significantly impact eastern Canada, including the Maritimes, but it may reduce tropical cyclone activity in the Atlantic Ocean,” Environment Canada added on its El Niño web page.

Environment Canada explained that in the response to the El Niño signal, the jet stream position is such that it keeps warm and dry air across southern Canada to the Maritime provinces, bringing air temperatures that are milder than normal. Eastern parts of Canada also have milder winters but not to same extent (much milder) compared to the Canadian west. “There is some tendency historically for lower than normal precipitation in western Canada and around the Great Lakes especially in winter, although these impacts are less certain than for temperature,” the information said.

Record or not, North American forecast quality is influenced by this kind of phenomenon (El Niño or La Niña) from west to east, Environment Canada said. “Our level of confidence in the seasonal forecast is usually increased, especially over western Canada and Canadian territories, if there is an El Niño,” the information said. “This statement is true especially for this winter and next spring.” Environment Canada noted that the months of September and October have been ‘transitional months,’ and the forecast for November 2015 “verified very well indeed.”

Environment Canada concluded that it is important to remember that general warming impact for winter over Canada represents a seasonal average and important variation (month-to-month, week-to-week and day-to-day) will happen within the winter season itself. For example, cold spells may occur even when the average winter temperature is warmer than normal.