No scientific basis for winter predictions

Although accuweather.com is forecasting the coldest winter in 20 years there is no specific scientific information.

  • Nov. 2, 2011 7:00 p.m.

Although accuweather.com is forecasting the coldest winter in 20 years, Jim Steele, a meteorologist with Environment Canada, said there is no specific scientific information to base that prediction on.

“They are a private organization. They put out what they want,” he said.

You can maybe forecast weather for five to seven days, but any predictions for extended periods of time are only outlooks, and they can be terribly misleading.

The basis of the forecast is the presence of La Nina, which Steele explained is a term used for water temperatures in the equatorial Pacific region, which is somewhat related to the storm pattern in the Pacific, but there are other factors.

For example, in the 50s, there were three La Ninas which resulted in very cold winters. In the last decade there were also three La Ninas during which winters were normal or above normal.

“It’s water cooler talk. I wouldn’t bet the farm on it. There is some correlation between La Nina with colder winters in B.C. but if we get one or two arctic blasts, that can skew the temperatures in a hurry. Same as the Pineapple Express. That can throw it off as well.”

Perception, he said, is another issue.

For example, most city residents would agree that it was a terrible summer with oodles of rain and cooler temperatures. But if you take the 90 day average into consideration things really weren’t so bad.

In fact, on average temperatures were just one degree below normal.

So if winter hits and there is a mild October and November then an ugly December, or the other way around, perception will dictate people’s recollection of the season when, on average, it might have been … well … average.

“It’s probably the most misunderstood prediction you can get,” Steele said. “There are so many factors that can skew the outlook.”

At the beginning of November Environment Canada will share an outlook, not a forecast, regarding what residents can expect weather wise this winter.

Delynda Pilion, Prince George Reporter