By J.W. Schnarr
Southern Alberta Newspapers
One of the strongest El Ninos on record is expected to make for an unseasonably warm and dry winter, say meteorologists.
“Overall, we’re expecting a fairly mild winter, and that’s in terms of temperatures and also snowfall,” said Brett Anderson, senior meteorologist and lead Canada forecaster for Accuweather.
Anderson noted the main reason for the change will be the El Nino weather pattern coming from the Pacific Ocean.
“It’s probably going to be one of the top three or top two strongest El Ninos on record,” he said. “This is going back to the 1950s.”
El Nino is the abnormal warming of surface ocean water along the equator in the Pacific Ocean.
It is caused by a change in the wind direction in the region which localizes warmer water and affects the jet stream, particularly in the winter and across North America.
“In a typical winter, what we usually see is one big jet stream that comes in off the Pacific, bringing storms across the country before continuing on,” said Anderson.
“With El Nino, the jet stream ends up splitting into two before reaching North America.”
The southern jet stream contains much of the moisture, and will work its way south through the United States.
The northern band of the jet stream will move up into the Yukon and act as a strong barrier against the cold.
“That leaves much of (Western Canada) in a void,” he said.
“So it’s not extremely cold, and it’s not extremely stormy. Thus, the forecasts are drier and milder for much of Western Canada.”
Anderson said scientists are still working on the causes of strong El Ninos, which he said occur about every 10 to 12 years.
The last really strong El Nino occurred in the winter of 1997-98.
He noted climate change may be having an effect on El Ni-o as well, something scientists are also investigating.
“With climate change, we’re seeing ocean water temperatures continue to warm, especially in the Pacific,” he said. “We have some of the warmest water we’ve seen. With climate change, there is evidence that it could be enhancing El Ni-o and making them stronger. That’s not etched in stone, but it kind of makes sense. If it’s warming the water, that we’d see even stronger El Ni-os into the future.”
Anderson said the expected dry conditions throughout the winter, and particularly January and February, could be an issue for farmers come spring.
“We’re expecting drier conditions also in the mountains, with less snow,” he said. “So when the spring melt drains into the Prairies, we think that’s going to be reduced. That is certainly a concern.” He added the spring forecast has not yet been completed, but that the El Ni-o impact could be felt until at least next March.
“It’s been dry obviously in much of Alberta,” he said. “And certainly I would be most concerned in southern Alberta compared to places like Saskatchewan.”
The good news is that a mild winter usually means lower heating costs.
“One good thing is we should have some savings on our pocketbooks in term of heating costs,” he said. “We could be seeing temperatures anywhere from two to four degrees Celsius above normal for the entire winter. But right now it doesn’t look like we’re going to see a lot of snowpack this winter.”
Perhaps the biggest question on the minds of local residents this year is whether El Ni-o will bring with it a green or white Christmas. Anderson backed away from a full prediction, saying there were too many variables involved.
“Odds favour a green Christmas,” he said. “But I’m not going to predict any more than that. It only takes one storm, and I can’t tell you when that storm is going to be.”