Canada: Water deficits forecast with pockets of exceptional deficits in BC, AB, MB, ON, QB, and NL

The Big Picture
The outlook for Canada through December 2016 (below) indicates widespread water deficits of varying severity across the country with pockets of exceptional deficits expected in parts of British Columbia, Alberta, Manitoba, Ontario, Quebec, and Newfoundland.*

Impacts
On April 18 the temperature in Vancouver hit 25.3C (77.5F), a temperature higher than the July average. A state of emergency was declared in the Peace River Regional District of northern British Columbia as 48 wildfires burned and evacuation orders were issued. Fire danger in the area is high due to recent dry weather and high winds. According to one local farmer, conditions have been exceptionally dry, drier than he's seen in 67 years of farming, exacerbated by a mild winter and early snow melt.

After last year's drought, farmers and ranchers in southern Alberta are also worried about the upcoming season. Much of the southern half of the province has received below 40 percent of normal precipitation over the last two months. Agroclimate specialist Trevor Hadwen at Agriculture and Agri-Food Canada echoes farmers concerns: "You've received extremely low precipitation compared to long-term normals. You're looking at a situation that happens probably once every 25 to 50 years."

Forecast Breakdown
As indicated in the 3-month maps (below) for the same 12-month period, abnormal (3-5 year) to exceptional (greater than 40 year) deficits are forecast for much of the country through December, with deficits gradually diminishing throughout the period. Large pockets of exceptional deficits are forecast April through June in British Columbia, Alberta, northern Manitoba, eastern Ontario, Quebec, and southern Newfoundland. Pockets of exceptional water surpluses are expected in southern British Columbia, northern Saskatchewan, and central Manitoba.

From July through September conditions are expected to improve somewhat, as larger pockets of exceptional deficits shrink in Alberta, Ontario, Quebec, and Newfoundland. However, deficits will persist across the country. Deficits are forecast on the Fraser River in central British Columbia and on the Peace and Athabasca Rivers in northern Alberta. By October water deficits are forecast to moderate in severity and extent. Moderate deficits may emerge along the South Saskatchewan River.

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

* Please note that effective March 28, 2016 NOAA changed the initialization procedure for CFSv2 to address issues with unrealistically cold sea surface temperatures in the Tropical Atlantic Ocean. As a result, this month's Watch List is based on an ensemble of 14 CFSv2 forecasts issued after this fix was implemented instead of the normal 28. For more information see http://www.nws.noaa.gov/os/notification/tin16-09cfs.htm and http://www.nco.ncep.noaa.gov/pmb/changes/downloads/CFSv2_Atlantic_cold_bias_problem.pdf.