Nova Scotia

Why February was so balmy and mostly snow-free in Nova Scotia

If you think it's been balmy out lately, you're right, but February's temperatures in Greenwood, Halifax, Sydney and Yarmouth weren't quite record-setting.

Location of jet stream and storm tracks helped fuel mild February that almost set records

A man walks across a snow-free Citadel Hill in Halifax on Wednesday, Feb. 21, 2018. (Darren Calabrese/Canadian Press)

It was close, but no cigar when it came to setting warmest-average daily temperature records for February in Yarmouth, Greenwood, Halifax and Sydney. However, there were some notable statistics this past month.

The average temperature at the Halifax Stanfield International Airport was –1.2 C, which was the second-warmest February on record going back to 1961. The warmest February is still 1981, which had an average daily temperature of –1.1 C. That's right — the record was missed by one-tenth of a degree.

Taking into account records around the Halifax area that include reports from near the city centre, February ranks as the sixth warmest using records going back to 1872. That's a bit of an unfair comparison for 2018 because the city centre has more of a marine influence than the airport location, so more moderate temperatures are expected through a winter season.

Yarmouth had the second-warmest average daily temperature on record, at 0.8 C, using records going back to 1880.

Greenwood had the fourth-warmest average daily temperature on record, with –1.1 C, going back to 1943.

Sydney had the 17th warmest average daily temperature on record, with –3.3 C, using records going back to 1870.

Why was February so mild and snow-free?

Do your snow-shovelling muscles not feel as primed as they should be this of year? Well, there's a good reason for that.

While not record minimums, all four sites reported February snowfall totals of less than 30 centimetres. That's pretty impressive, considering a decent nor'easter could easily give us that amount or even double in one go.

There were a combination of factors fuelling the balmy month.

Through much of February, particularly toward the end of the month, the jet stream became stalled in a position that had it dipping far to the south in Western Canada before climbing back north around Atlantic Canada.

This placed Nova Scotia on the warmer, southern side of the jet stream for prolonged periods, allowing more mild, warm air masses to move up the Eastern Seaboard and into the region.

Another factor was storm track. Typically, when a big low-pressure system moves through the region in the winter, conditions are cold and snowy to the northwest of the centre of the storm, and mild and rainy to the east of the storm's centre.

When we did see lows move through this February, Nova Scotia most often ended up on the warmer, eastern side of these weather systems.

Variability not uncommon

Year-to-year variability in snow and temperatures is not uncommon for Nova Scotia for the month of February.

While this year was mild and relatively snow-free, both February 2015 and 2017 featured colder temperatures and much more snowfall.

In fact, both of those years are solidly in the top 10 snowiest Februaries on record for most of Nova Scotia.

ABOUT THE AUTHOR

Kalin Mitchell

Meteorologist

Kalin Mitchell is a former meteorologist on CBC News Nova Scotia, CBC News New Brunswick and CBC News Atlantic Tonight.

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