Global warming is complicating efforts to forecast how a developing La Nina weather system will affect the Canadian Prairies.
Amir Shabbar, a research meteorologist with Environment Canada, said a La Nina is developing and is expected to mature this winter.
It typically brings cooler temperatures and above normal precipitation, but a warming trend combined with La Nina generally means warmer than normal values for the West.
These two systems appearing
together complicate ordinary weather forecasting for scientists, who base their theories on climate models, studies of sea surface temperatures, northern ice conditions and soil moisture.
“This warming trend is the fly in the ointment,” Shabbar said. “In the last 10 to 15 years, the nature of La Nina has been changing due to the warming trend in our climate.”
A forecast expected in late November will give a clearer picture of what winter will look like, he said.
A weather outlook issued in early September predicted near normal temperatures for the Canadian Prairies, except in extreme northern regions where above normal values were predicted.
