Canada: Moderate water deficits forecast for southeastern ON

September 26, 2016

The Big Picture
The outlook for Canada through May 2017 (below) indicates large pockets of exceptional water deficits (greater than 40 years) in central Alberta, northern Manitoba, eastern Ontario, and central Quebec. Deficits of generally lesser severity are forecast across the Prairie Provinces.

Impacts
In Yarmouth, Nova Scotia the summer of 2016 is going down as the driest summer since 1880. The local weather observation station recorded 86.6 mm (3.4 inches) of rain over the summer, one-third of the 30-year climate normal of 267.5 mm (10.5 inches).

In nearby Shelburne County, NS "How's your well?" has become a standard greeting for residents, and many are toting water from public washrooms and the fire department. One third-generation homeowner says it's the first time in over 100 years that the family's well has gone dry, and others say that they haven't had to mow their lawns since Canada Day, July 1. Citing records that go back to 1915, the Canadian Hydrographic Service reported that the Roseway River into Shelburne Harbour is at its lowest level ever.

In a growing season beset by both drought and drenching in Ontario, crop forecasts for corn are varying widely, from 32 bushels an acre (2,010 kg/ha) in Norfolk County to 230 bushels (14,400 kg/ha) in Elgin County. Some areas in Haldimand and Niagara could record zero yield, according to farmers' co-op Great Lakes Grain. Similarly, some soybean fields to the east and north of London won't even be harvested, while Kent, Middlesex and Elgin Counties could see near-record high soy yields.

Forecast Breakdown
The 3-month maps (below) show the evolving conditions in more detail. As seen in the September through November map, areas of exceptional deficits are expected to shrink in the next three months though large pockets will persist in northern Manitoba and central Quebec. Mostly moderate (5 to 10 years) deficits are forecast to persist in Southern Ontario from London through Toronto up to Ottawa, but a pocket of exceptional deficits may persist to the northeast between the St. Lawrence River and Sherbrooke, Quebec. Moderate to extreme (20 to 40 years) surpluses are forecast to emerge in the southwestern corner of Northern Ontario from Kenora north and persist through February.

From December through February surpluses will continue to emerge in southern British Columbia in the Columbia Mountains; farther north along the central border of BC and Alberta near Grande Prairie, Alberta; and in the Williston Lake area of BC. Moderate deficits are expected to persist in northern Manitoba, and pockets of exceptional deficits will persist in central Quebec.

Deficits are forecast March through May in northern Manitoba, throughout Ontario, much of Quebec’s southern half, and from Montreal through New Brunswick.

(It should be noted that forecast skill declines with longer lead times.)