2021 Great Lakes Current and Historical Water Levels (December Update)

Updated December 18th. Excepts from the Army Corps of Engineers – Detroit District’s Monthly and Weekly reports for Great Lakes Water Levels and Great Lakes Water Level History.

All The Great Lake’s Are Dropping From Record Water Levels

The projected December 11th water levels for Lakes Superior, Michigan-Huron, St. Clair, and Erie are below their water levels a month ago by 2 to 4 inches. In contrast, Lake Ontario’s projected level matches its level of a month ago. Besides, the forecasted December 11th water levels for Lakes Superior, Michigan-Huron, St. Clair, and Erie range from 1 to 4 inches below what they were a year ago, while Lake Ontario’s predicted level is 15 inches below its level of a year ago.

The lakes remain above their long-term monthly average December levels, but all are below their record-high December monthly mean levels. By January 11th, Lakes Superior and Michigan-Huron’s water levels are expected to be 2 and 3 inches, respectively, below their December 11th projected levels. The levels of Lakes Erie and St. Clair are projected to be near their December 11th projected level a month from now, while Lake Ontario’s predicted January 11th level is 3 inches higher than its projected December 11th level.

Lake Huron Water Level

Lake Huron Water Level Dec 2020

As of December 25, 2020, the Lake Huron water level is forecasted to be 581.07 feet. This is 6 inches less than the record water level set in 1986 and 59 inches higher than the lowest record set in 2012. Over the next month, Lake Huron is expected to drop another 2 inches.

Lake Michigan Water Level

As of December 25, 2020, the Lake Huron water level is forecasted to be 581.07 feet. This is 6 inches less than the record water level set in 1986 and 59 inches higher than the lowest record set in 2012. Over the next month, Lake Michigan is expected to drop another 2 inches.

Lake Superior Water Level

Lake Superior Water Levels Dec 2020

As of December 25, 2020, the Lake Superior water level is forecasted to be 602.40 feet. This is 8 inches less than the record water level set in 1985 and 27 inches higher than the lowest record set in 1925. Over the next month, Lake Superior is expected to drop another 3 inches.

Lake St. Clair Water Level

Lake St. Clair Water Levels December 2020

As of December 25, 2020, Lake St. Clair’s water level is forecasted to be 576.08 feet. This is 8 inches less than the record water level set in 1986 and 53 inches higher than the lowest record set in 1964. Over the next month, Lake St. Clair is expected to drop another 1 inch.

Lake Erie Water Level

Lake Erie Water Level December 2020

As of December 25, 2020, Lake Erie’s water level is forecasted to be 572.93 feet. This is 10 inches less than the record water level set in 1986 and 57 inches higher than the lowest record set in 1934. Over the next month, Lake Erie is expected to remain at this water level.

Lake Ontario Water Level

Lake Ontario Water Level December 2020

As of December 25, 2020, Lake Ontario’s water level is forecasted to be 244.72 feet. This is 24 inches less than the record water level set in 1945 and 33 inches higher than the lowest record set in 1934. Over the next month, Lake Ontario is expected rise by 4 inches.

Downbound Outflows Expected To Be Above Average

Lake Superior’s outflow through the St. Marys River is predicted to be above average this December. Lake Michigan-Huron’s outflow through the St. Clair River and Lake St. Clair’s outflow into the Detroit River is forecasted to be above average for December. Lake Erie’s outflow into the Niagara River is predicted to be above average for December. Lake Ontario’s outflow through the St. Lawrence River is projected to be above average in December.

Long Term Great Lakes Water Level Estimates

Near-record, high water levels continue on some of the Great Lakes. Water levels follow a seasonal cycle where water levels rise in the spring due to increased precipitation and enhanced runoff from snowmelt. In the fall, the lakes generally decline due to an increase in evaporation as temperatures decline and cold air moves over the relatively warm lake waters. We refer to the combined effect of precipitation over the lake, evaporation from the lake, and runoff to the lake as Net Basin Supply (NBS). This edition of the Water Level Outlook shows a purple plume representing NBS sequences from years when a La Niña developed in the prior spring, summer, or fall and lasted through the winter. Two years within the plume have been specifically called out to evaluate what occurred during those years compared to 2020. These two years are 2005-06 and 2010-11. The green line represents the water levels that would occur if the same NBS sequence were to occur in 2005-06 over the next 12 months. The blue line represents water levels resulting from the NBS sequence from 2010-11 to reoccur over the next 12 months. The most recent coordinated 6-month forecast is also shown for comparison.

Water levels for all the Great Lakes declined from August to September. Lake Superior declined about 1 inch, while Lakes Michigan-Huron, St. Clair, and Erie declined by 3 to 4 inches from August to September. Lake Ontario also dropped 8 inches in the last month. In September, the monthly mean level for Lake St. Clair was a new record high, which surpassed its previous record high from last year by 1 inch. The current 6-month forecast predicts all lakes to continue their seasonal water level declines throughout the fall.

These levels project to make 2020 a record year.

This past August, La Niña conditions developed in the equatorial Pacific Ocean. This means that the sea surface temperatures in the eastern and central equatorial Pacific Ocean are cooler than normal.
When this occurs, there can be impacts on the weather experienced in the Great Lakes region, especially in the winter. The current forecast issued by the Climate Prediction Center expects that La Niña will last through the winter. Figure 1 depicts the weather conditions that typically occur then a La Niña is present in the winter. For the Great Lakes basin, southern portions of the basin could experience wetter than normal conditions, and colder air could push further south into the region.

2020 Yearly Great Lakes Water Level History

Lake Michigan-Huron has set a record high monthly mean level for 9 consecutive months. Also, the August 2020 level was 4 inches above its August 2019 level and 33 inches above its August Long Term Average level.

Weather Outlook for the Rest of 2020

The recent 1-month climate forecast updated by the Climate Prediction Center shows a likelihood of above-normal temperatures for October. The forecast for precipitation in October indicates the likelihood of below-normal precipitation for the entire Great Lakes basin.

The seasonal three-month outlooks for temperatures in the late fall and early winter (October, November, December) indicate a likelihood of above-normal temperatures throughout the Great Lakes basin. The seasonal three-month outlook for precipitation generally shows equal chances of above, below, or normal precipitation.

Dynamic Great Lakes – Lake Level Viewer – From NOAA

Daily Great Lakes Water Level History

The report below is a view of long-term, basin-scale hydrological data for the Laurentian Great Lakes. Water levels are continuously observed by U.S. and Canadian federal agencies in the region through binational cooperation. NOAA-GLERL relies on this water level data to conduct research on the regional water budget components and improve predictive models.

NOAA’s Center operates water level monitoring stations for Operational Oceanographic Products and Services and the Department of Fisheries and Oceans’ Canadian Hydrographic Service. The U.S. Army Corps of Engineers (Detroit, Chicago, Buffalo) and Environment and Climate Change Canada play crucial roles in research, coordination of data, and operational seasonal water level forecasts for the basin.

Observed Lake Huron Water Levels at Harbor Beach, Michigan

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Current Weather and Lake Huron Conditions at Harbor Beach Michigan

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