Plunging world oil prices have delivered a Christmas miracle of lower gasoline prices across most of Canada but a fuel price expert says motorists should fill up now ahead of an expected increase this weekend. (Michelle Siu / THE CANADIAN PRESS) CALGARY — Plunging world oil prices have delivered a Christmas miracle of lower gasoline prices across most of Canada but a fuel price expert says motorists should fill up now because prices are expected to be volatile in 2019. Dan McTeague, a senior petroleum analyst at GasBuddy.com , says gasoline prices are at near-18-month lows because of global oil prices that have tumbled over the past two months on worries of an economic downturn, a U.S.-China trading tiff and concerns that members of the OPEC oil cartel won’t live up to production cuts. Despite a brief oil price rally on Wednesday, average regular gasoline prices remain about 17 cents lower per litre than a year ago in Alberta and Ontario, 12 cents lower in Manitoba, six cents lower in Quebec, 11 cents lower in Nova Scotia and three cents lower in Newfoundland and Labrador. McTeague says prices in B.C. are up two to six cents per litre compared […]