While there is a small chance of snow before Dec. 25, warm weather will likely bring a green Christmas throughout the county.
Geoff Coulson, meteorologist with Environment Canada, explained the best chance for snowfall would happen late this week or early next week.
“Being not much in the way of snowfall and with those warm temperatures being forecasted in the days leading up to Christmas, it would be hard at this point in time to think we’ve got much of a chance of a white Christmas,” he said on Dec. 14.
Coulson explained El Nino is to blame for the aberrant weather.
“El Nino is the warmer-than-normal waters in the Pacific Ocean off the coast of South America and these warmer-than-normal waters can influence the jet stream patterns, circulation patterns, the air masses that influence southern Ontario,” he said, adding the result of which is a milder-than-normal fall in the Great Lakes basin.
The Grand River Conservation Authority (GRCA) has looked at how the watershed responded during two strong El Ninos in 1982 and 1997 to get a sense of how it will respond this time around, explained Dwight Boyd, director of engineering for GRCA.
“Typically what it means is that we have a warmer winter and we typically can have a drier summer,” he said.
The forecast will help the GRCA with how it operates its reservoirs following an El Nino.
“We know how the watershed has operated in the past and it just makes us be aware that we could have a warm winter with many melts and maybe light snow, so we’re going to very carefully keep an eye on how we operated the reservoirs,” he added.
El Nino is also the cause of the plethoric fog in the region lately.
Coulson explained mild temperatures bring more moisture in the lower levels of the atmosphere. Combined with little stir in the atmosphere and winds from the south, that creates full days of foggy conditions.
“The fog that we’ve been seeing recently, if we have temperatures that are a little bit cooler, that’s frost on the trees or if you’re getting rain with that, that’s freezing rain on the trees,” said Boyd.
“It doesn’t take a lot of temperature difference right now to trigger us into an ice storm if you get the moisture and the cold temperatures.”
Winter season outlook
Coulson predicts the warmer weather will last into January but there’s a possibility for winter to arrive in full force by the end of next month.
“There’s still that possibility (for a delayed winter). We know the cold air will eventually make it’s appearance for a longer period of time as we go through the winter months,” he said.
“So there is that possibility later on in January, through the month of February, we could see more in the way of seasonal temperatures, but certainly the overall trend at this point in time for the rest of December and at least into the first part of January is for a continuation of what we’ve seen so far.”
As for the possibility of ice storms, Coulson said it is too early to tell, but they can’t be ruled out.
While freezing rain is a possibility every winter, in an ice storm, the freezing rain continues without being able to melt.
“Too early at this point to say if we’ll get an extended period of freezing rain such as we got back in December 2013 or January ‘98,” said Coulson.
“But we do know that moving forward as we have more opportunity to get some of this colder air, perhaps later on in January, there will be that possibility of more in the way of messy weather.”
More green Christmases
The climate is changing in the Waterloo-Wellington region, at least, that’s what the numbers are telling the team at Environment Canada.
Coulson said the team looked at numbers based on past winters to calculate the chance of snowfall during Christmas for the past 60 years and the past 20 years to see how they differ.
The period from 1955 to 2013 showed a 70 per cent chance of having snow by Christmas day. From 1994 until now, the chance is lower, at 60%.
“Saying over the last 60 years or so the chance of 70 per cent – that’s pretty good odds of having a white Christmas. But seeing in the last 20 years, we’re down to 60 per cent, that’s really not all that far away from a coin toss as to the chance of actually experiencing a white Christmas,” Coulson said.
“There could be as we go forward in the coming decades smaller and smaller chance of having a white Christmas in the area.”
