Many forecasts, but only one will be correct

No one source has had a monopoly on predicting the winter weather well over the past several years. This week, the Weather Network released a seasonal forecast calling for a long, cold and messy winter across much of Canada, with P.E.I. not bitterly cold specifically, but predictions of a stormy season.

So, I think it is time for the UPEI Climate Lab’s annual winter predictions for Prince Edward Island.

Environment Canada uses climate models to forecast seasonal weather, which are mathematical equations strung together that describe the chemistry and physics of the Earth’s climate system. Environment Canada forecasts temperatures for the coming winter (December, January, February) for P.E.I. to be “normal” with precipitation (snow and rain) “normal” for the Island. Environment Canada’s seasonal forecast models are accurate for P.E.I. only 40-50 per cent of the time, which is not significantly better than chance, meaning flip a coin and you’ll have the same odds of getting the forecast correct.

We all know people who swear by almanacs when forecasting the seasonal weather, so we took a look at the predictions from four of them. The 2020 Canadian Farmers Almanac forecasts the winter as “cold, very wet and white” while the 2020 Almanac for Farmers and City Folk predicts normal temperatures and below normal precipitation. The 2020 Harrowsmith’s

Almanac says the winter will “bring abundant amounts of snow,” and “turn sharply colder” at the end of December, and the 2020 Old Farmer’s Almanac has forecast the P.E.I. winter climate this year to be below average temperatures and precipitation.

The Old Farmer’s Almanac is the one we are most familiar with as it has been forecasting seasonal weather since its first issue in 1792 (the time of George Washington’s presidency) using a “secret formula” kept tucked away in a black tin box at the Almanac offices in Dublin, New Hampshire.

My own research at the University of Prince Edward Island that examined over 140 years of weather observations in Charlottetown has shown that the climate has definitely gotten warmer and drier, especially over the past 10-15 years or so. And that’s where I put my forecast each winter – to continue the trend and be “warmer and drier.”

Over the past seven years, no one source has been “bang on” in predicting the winter climate – the best has been following the long-term climate trends of warmer and drier but this only worked three out of the past six years, and really missed our savage winter of 2015. Normally, a P.E.I. winter (the months of December, January and February) averages -6 C (degrees Celsius) and receives about 303 millimetres of precipitation, that’s rain or snow. The 2018-19 winter was colder than normal (-6.6 C, or 0.6 degrees colder) and drier than normal (228 millimetres, or about three-quarters of normal). Last year, only the

Harrowsmith’s Almamac predicted both of those. Congrats to them.

Climate is nature’s merry-goround so it is often difficult to predict the coming season even with supercomputers, secret formulas or historical trends. To emphasize this point, my new colleague at the UPEI Climate Lab, Dr. Xander Wang, flipped coins to see what Lady Fortune’s forecast for the winter will be – the result being “colder and wetter.”

So there are many forecasts made, but only one will be correct. Predictions overall are leaning towards a colder winter with average rain or snow for 2019-20.