Great Lakes quarterly climate impacts and outlook: December 2016

December 2016

Great Lakes Significant Events - for September-November 2016

Figure 1: Great Lakes significant events - for September-November 2016
Map of significant events (see long description below)
Long description

Figure 1: A map of the Great Lakes displaying key highlights from the significant events section. The highlights are as follows: Strong gale-force winds on November 19-20 produced large waves over 7m (24ft) on the south shoreline of Lake Superior. Locations across the Great Lakes basin experienced their warmest fall on record, while many others experiences near-record fall warmth. Water levels of the upper Great Lakes remain above average, while Lake Ontario ended the season slightly below average. Despite drier fall weather in many places, Syracuse, New York measured its 2nd wettest October on record. A strong lake effect snowfall event from November 20-21 dumped 138.4 cm (54.5 in) in Oswego County, New York.

Fall 2016 was unseasonably warm across the entire Great Lakes basin. In the U.S., Michigan, Minnesota, and Wisconsin experienced their warmest fall season in 122 years of records, while it was the 2nd warmest for Illinois, Indiana, and Ohio. In Ontario, Toronto, Hamilton, Gore Bay, and Sudbury also experienced their warmest fall on record.

Despite a few noteworthy precipitation events, conditions in the Great Lakes were generally dry over the past three months, the exception being Lake Superior, where water supplies were slightly above average. This was offset by high Lake Superior outflows, and dry conditions elsewhere resulted in all lakes declining more than average during the fall.

The Windsor area in southwestern Ontario was deluged by a significant rainfall event from September 28-30. The Windsor airport reported over 110 mm (4.3 in) from the event, while volunteer rain gauge reports just north of the airport in Tecumseh measured amounts in excess of 190 mm (7.5 in).

Strong gale-force winds raced across the Great Lakes on November 19-20. Marquette, Michigan reported gusts of 80-97 km/hr (50-60 mph), resulting in very large waves of over 7 m (24 ft) on the southeastern shoreline of Lake Superior. Strong westerly winds over Lake Erie produced a storm surge event, raising the water level by 0.6 m (2 ft) on the eastern edge by Buffalo, New York and dropping the water level by 0.8 m (2.5 ft) at the western edge by Toledo, Ohio.

Unseasonably warm lake temperatures contributed to a significant lake-effect snowfall event in the eastern Great Lakes from November 20- 21. The highest storm total of 138.4 cm (54.5 in) was recorded in Oswego County, New York, while numerous areas measured 30.5 cm (12 in) or greater. This storm was the greatest 2-day November snowfall on record in Syracuse, New York.

Regional Climate Overview - for September-November 2016

Precipitation

September precipitation ranged from 65% of average in the Lake Ontario basin to 123% of average in the Lake Erie basin, with the Great Lakes basin at 101% of average. All lakes basins saw near to above-average precipitation in October (106% overall) and near- to below-average precipitation in November (77% overall). Fall precipitation was near-to below-average for the individual basins, with the Great Lakes basin receiving 95% of average.

October and November 2016 graphics are shown to display the range in precipitation this fall.

Figure 2: Precipitation, October and November 2016
Map showing the precipitation (see long description below)
Long description

Figure 2: Maps of the Great Lakes showing precipitation as the percent of normal for October 2016 (A) and November 2016 (B). Shades of brown on left map show that precipitation has been below normal west of lake Superior and north of lakes Huron, Erie and Ontario. Elsewhere, precipitations were above normal especially south of lakes Erie and Ontario. Shades of brown on right map show that precipitation has been below normal across the basin, except for an area west of lake Superior.

Air temperature

In September and October, temperatures ranged from 0.5 to 4°C (1 to 7°F) above normal, with most areas 1 to 3°C (2 to 5°F) above normal. November temperatures ranged from 0.5°C (1°F) above normal east of Lake Ontario to more than 5°C (9°F) above normal in the western half of the Lake Superior basin. With all three months warmer than normal, fall temperatures ranged from 1 to 4°C (2 to 7°F) above normal (right).

Figure 3: Temperatures, September-November 2016: departure from normal (%)
Maps showing the temperature departures from normal (see long description below)
Long description

Figure 3: Maps of the Great Lakes showing the temperature departures from normal in degrees Celsius for September-November 2016. Light to medium-pink shades show that the entire Great Lakes basin experienced temperatures that were up to 3°C (5.4°F) above normal.

Water temperature

The fall season saw average water temperatures that were 1.1 to 4.6°C (2 to 8.3°F) above the long-term average (LTA). November surface temperatures were particularly warm compared to the LTA (left).

Air temperature normals based on 1981-2010. Water temperature long-term average is 1995-2015.

Great Lakes water levels

Great Lakes water levels
Lake End of Nov. Water Levels Change since
September 1
2016 Compared to:
Average Last Year 2016 Average
Superior 183.58 m
(602.3 ft)
+14 cm
(+5.5 in)
+1 cm
(+0.4 in)
-12 cm
(-4.7 in)
-10 cm
(-3.9 in)
Michigan-Huron 176.56 m
(579.3 ft)
+22 cm
(+8.7 in)
+4 cm
(+1.6 in)
-24 cm
(-9.4 in)
-18 cm
(-7.1 in)
Erie 174.18 m
(571.5 ft)
+20 cm
(+7.9 in)
-2 cm
(-0.8 in)
-27 cm
(-10.6 in)
-23 cm
(-9.1 in)
Ontario 74.49 m
(244.3 ft)
-7 cm
(-2.8 in)
-4 cm
(-1.6 in)
-34 cm
(-13.4 in)
-29 cm
(-11.4 in)

Regional Impacts - for September-November 2016

Drought

Drought conditions have slightly improved from last season in the eastern Great Lakes basin. Above-normal precipitation in October helped remove extreme drought in western and central New York. However, as of November 30, areas remain in moderate to severe drought.

Figure 4: Drought conditions, November 30, 2016
Maps showing the drought conditions on November 30, 2016 (see long description below)
Long description

Figure 4: Maps of the Great Lakes showing drought conditions on November 30 2016. Shades of yellow, orange show abnormally dry and moderate drought conditions for the southern and eastern parts of the basin. Severe drought (dark orange) is observed north of Lake Ontario.

Agriculture

The warm and relatively dry weather resulted in the harvest season being ahead of schedule this year in many locations across the basin. However, lower yields of corn and soybeans were reported in western New York and northern Ohio due to dry conditions. In the Niagara region in Ontario, and along the North Shore of Lake Ontario, hay, corn, and soybean crops were negatively impacted in growth and development due to low soil moisture and surface water supplies.

Water Resources

Deficits in groundwater have been reported across the eastern Great Lakes basin. In Ontario, the Grand River Conservation Authority has been augmenting water flow with water stored in its three major reservoirs. Residents near Clarington, Ontario have reported low water levels in wells due to drought, with some reporting no running water for months. In western and central New York, several waterways and well sites had record or near-record low levels through mid-October.

Storm Impacts

The September 28-30 heavy rainfall event near Windsor, Ontario resulted in insurable loss estimates of just over $100 million (CAD), mainly from flooded basements and other infrastructure damage. The November 19-21 lake-effect snow event resulted in more than 27,000 power outages in the Rochester, New York area, as well as highway closures and accidents.

Water Quality

The 2016 harmful algal bloom (HAB) in Lake Erie was more mild than the blooms of 2013-2015, mainly due to drier conditions and less runoff (and therefore less phosphorus) into the lake. However, bloom biomass was more toxic than last year. Even though bloom biomass was more toxic, no drinking water advisories were issued. This indicates that bloom severity does not always equate to increased risk and highlights the ability of municipalities along Lake Erie to successfully treat incoming water.

Regional Outlook - December 2016-February 2017

Lake ice cover

Winter 2016/17 is favored to have below-normal temperatures in a majority of the Great Lakes region. Therefore, NOAA’s Great Lakes Environmental Research Laboratory is forecasting maximum ice coverage of the Great Lakes to be about 64% this winter, above the long-term average of 55% (see figure for individual lakes). This forecast results from the presence of a weak La Niña, a neutral North Atlantic Oscillation, and a weak Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation.

Figure 5: Potential range for maximum ice cover outlook, winter 2016-17 compared to the long-term average (1918-2015)
Map showing the potential range for maximum ice cover (see long description below)
Long description
Potential range for maximum ice cover outlook, winter 2016-17 compared to the long-term average (1918-2015)
Lake Forecasted maximum ice cover in percentage Long-term average in percentage
Superior 76% 64%
Huron 69% 62%
Michigan 45% 38%
Erie 92% 85%
Ontario 32% 25%

Lake levels

Great Lakes water levels are typically at their lowest during winter due to higher evaporation rates and reduced basin runoff at this time of year. Levels on lakes Superior, Michigan-Huron, and Erie are expected to remain above average, but below record highs, unless exceedingly dry or wet conditions are experienced. Lake Ontario water levels are expected to remain near average unless exceedingly dry or wet conditions are experienced.

Figure 6: Potential range for water levels for October-December 2016 compared to the long-term average (1918-2015)
Map showing the potential range for water levels (see long description below)
Long description
Potential range for water levels for October-December 2016 compared to the long-term average (1918-2015)
Lake Forecasted high compared to the long-term average in centimetres Forecasted low compared to the long-term average in centimetres Forecasted high compared to the long-term average in inches Forecasted low compared to the long-term average in inches
Superior +17 cm above +3 cm above +6.7 in. above +1.2 in. above
Huron-Michigan +32 cm above +9 cm above +12.6 in. above +3.5 in. above
Erie +55 cm above +1 cm above +21.7 in. above +0.4 in. above
Ontario +32 cm above -21 cm below +12.6 in. above -8.3 in. below

Temperature and precipitation outlook

The Climate Prediction Center (CPC) predicts a greater chance for below-normal temperatures in the western U.S. Great Lakes basin and above-normal temperatures in the eastern U.S. basin for the January-March 2017 period. Environment and Climate Change Canada (ECCC) predicts above-normal temperatures for the entire Canadian basin. Above-normal precipitation is favored for a majority of the basin by both CPC and ECCC. With lake surface temperatures currently warmer than normal, this could increase the chance for lake-effect snow this winter. Also, the CPC predicts that drought conditions in the eastern basin will likely improve.

The current monthly and seasonal outlooks can be found through CPC and ECCC.

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