By John DeCoste
The Kings County Advertiser
Our weather has been fairly up-and-down of late, but according to the experts, with years of research at their disposal, it hasn’t really been anything out of the ordinary.
Tracey Talbot, a weather preparedness meteorologist with Environment Canada in Dartmouth, suggested this really hasn’t been that abnormal a year.
Fluctuations in temperatures, such as we have seen over the past couple of weeks, while “pretty extreme, are not that unusual.” For the past 50 years or so, the expected daytime highs for late November have averaged between three to five degrees above zero Celsius, with the average overnight lows between minus three to five degrees Celsius.
And while we have had temperatures lately some would probably term abnormally mild for this time of year, Talbot stressed, “this year hasn’t set any records.”
In 1953, a high temperature of 16.7C was recorded at Halifax during the last week of November. The lowest daytime high was -7.3C in 1978.
On the other end, the highest overnight low was plus 10.6 degrees in 1966, while the lowest overnight low for the end of November was -13C in 1976.
“It’s not that unusual to have temperature fluctuations in November,” Talbot said.
Nova Scotia’s geography, and being almost surrounded by water, means most weather systems approaching from the south are travelling over water.
With water temperatures at this time of year “generally warmer than the land, the water isn’t cooling the air down as much. And when cold air comes in when that system leaves, the temperature can drop drastically in a short period of time.”
While the weather in Atlantic Canada is notoriously hard to predict, Talbot expected “we might see more fluctuations in temperature between now and Christmas, depending on which direction the weather is coming from.”
The long-range weather projections for Nova Scotia in general suggest there is a good chance we will have above normal temperatures for probably the next two to three months, and possibly most of the winter.
In terms of precipitation, Talbot said, Environment Canada simply can’t say – or at least, not for much longer than a week in advance.
“It’s pretty challenging to try and predict, especially with so much of our weather coming over water. Sometimes you literally don’t know what’s coming until it actually arrives on your doorstep.”
As for the chances of a white Christmas? That depends on your definition. Talbot pointed out, “our definition of a white Christmas is a snow cover of at least two centimetres on Christmas morning.” Similarly, a ‘perfect Christmas’ is defined as “a measurable snowfall on Christmas Day.”
For the period between 1955-2011, the probability of a white Christmas in Nova Scotia has been 58 per cent. More recently, for 1992-2011, “the probability has been 45 per cent.”
So in a nutshell, depending on the weather patterns, there is still a decent chance for a white Christmas, “just maybe not as much of a chance as there used to be.”