WEATHER

Long-range outlook

Environment Canada tries 90-day forecasts

D’ARCY JENISH January 4 1993
WEATHER

Long-range outlook

Environment Canada tries 90-day forecasts

D’ARCY JENISH January 4 1993

Long-range outlook

WEATHER

Environment Canada tries 90-day forecasts

D’ARCY JENISH

Shortly after Halloween each year, Brian Rode begins watching the skies and hoping for snow. Rode, the marketing manager at Ski Marmot Basin, a Rocky Mountain ski centre near the town of Jasper, Alta., says that the resort usually has enough snow to open by the first week in December. But this year, below-average snowfalls kept Marmot Basin closed until Dec. 23. Unusual winter weather hit other parts of the country as well, just as Environment Canada, responding

to a demand for more weather information, has started issuing its first-ever 90-day national temperature forecasts. While Vancouver, which seldom receives much snow, was blanketed by 18 cm on Dec. 19, southern Quebec remained oddly free of snow before Christmas. In those circumstances, some Canadians whose livelihood depends on the weather greeted the new long-term forecasts with skepticism. Said Rode: “If somebody could really predict the weather perfectly in this country, that would be nothing short of miraculous.”

work is influenced by weather conditions, do not attempt to predict any more than temperatures. Meteorologists are usually unable to anticipate individual storm or weather systems with any accuracy more than five to nine days in advance, he said, and previous attempts to forecast even rain or snow levels over 30-day periods have been unsuccessful. Added Saulesleja: “Forecasting weather becomes very difficult after five days. But we are attempting to forecast departures from normal temperatures.”

For the past 10 years, Environment Canada has produced 30-day forecasts that attempt to show whether temperatures in various parts of the country will be above or below long-term averages. Andrej Saulesleja, chief of the department’s climate forecasting branch in Toronto, said that the 30-day and 90-day forecasts, of use mainly to farmers, fishermen and others whose

Saulesleja said that the agency added the service because the unusually cool, wet summer in many parts of the country led to heightened public interest in the weather, and concerns that the winter might be unusually hard. According to Environment Canada’s first 90-day forecast, covering December, January and February, that anxiety about a cold winter might be justified—depending on where Canadians live. It said that Alberta, Saskatchewan, much of Manitoba and the eastern Arctic would be in for below-average temperatures. But most of Central and Atlantic Canada, northern British Columbia, Yukon and the western half of the Northwest Territories could experience slightly higher-than-normal temperatures.

In their attempts to predict individual weather systems, meteorologists try to project the weather patterns that will result from ob-

served temperatures, precipitation levels and air pressures on a specific day. But, according to Alain Caillet, a Toronto-based Environment Canada meteorologist, experts can never take precise account of all the myriad factors that may change weather patterns. As a result, he conceded, the further a meteorologist moves from observed values the greater the potential for inaccuracy in forecasting events such as thunderstorms or blizzards. Still, Saulesleja said that with sophisticated statistical analyses, meteorologists can produce 30-day forecasts of slight variations in average long-term temperatures. Such information is useful to, among others, farmers who are trying to decide when to seed crops or how much acreage to devote to certain crops, he said.

But Environment Canada is still pursuing its study of long-range climate patterns. According to Roger Street, chief of the department’s climate change detection unit, it is testing theories that the earth’s climate is warming because of the emission of manmade carbon dioxide and other so-called greenhouse gases into the atmosphere. Street said that studies have shown that temperatures across Canada have risen by an average of 1.3° C since 1895. Departmental research has also shown that in many parts of Canada, winters have become milder during the past decade.

Still, Canadian winters have not lost their capability to deliver nasty storms. And despite the use of sophisticated radar and satellite technology, winter weather forecasting remains a difficult art. Indeed, Environment Canada meteorologists noted with delight that they accurately predicted the major storm that lashed southern Ontario in mid-December. Senior climatologist David Phillips said that the storm, which dumped from 30 to 50 cm of snow on many parts of the province during a two-day period, began in Texas and took three days to reach Ontar^ io. He said that meteorologists predict1 ed heavy snowfalls as soon as they began tracking the storm, and their forecasts became more precise as the disturbance moved north. Added Phillips: “Our meteorologists were wringing their hands with glee after that one. They take an almost perverse pleasure in being right.”

For many Canadians, the weather can be both a scourge and a source of fascination. Phillips said that the sheer size of the country ensures that a wide variety of weather conditions exists almost every day, particularly in the winter. Indeed, Environment Canada receives about 200,000 inquiries from the public each year about weather and climatic conditions. “For safety’s sake, people need to know what’s happening outside during the winter,” he said. “In this country, most people can’t go more than a couple of hours without a weather fix.” Even reliable three-month forecasts are unlikely to cure that national fixation.