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Weekly Forecast

ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

Nov 26, 2021

 

WEATHER CONDITIONS

Over the past week air temperatures have been slightly below normal for this time of year in most of the Great Lakes basins.  Last weekend the Great Lakes basins received some light precipitation, while total precipitation over the past week was generally about 0.5 inches.  Sault Ste Marie in the Lake Superior basin received about near an inch of precipitation, and some regions received less, such as the Michigan-Wisconsin border where very little precipitation fell over the past week.  In the coming holiday weekend, there is a forecast for a chance of snow and/or rain showers in various regions such as Duluth, MN; Grand Rapids, MI; Cleveland, OH and Buffalo, NY. 

LAKE LEVEL CONDITIONS

November 26th levels are forecast to be below the levels from last month on lakes Superior, Michigan-Huron, and St. Clair, while Lake Ontario is forecast to be 4 inches above last month’s level. The November 26th  levels are also forecast to remain below their levels from one year on, with the exception of Ontario is forecast to be above last years level.  Water levels remain above their long-term November average levels on all lakes, except Lake Superior. Over the next month, all lakes are forecast to decline by 2 to 3 inches. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Predictions indicate Lake Superior’s outflow through the St. Marys River will be below average in November. Forecasts show Lake Michigan-Huron’s outflow through St. Clair River and Lake St. Clair’s outflow into Detroit River will be above average for November. Predictions show Lake Erie’s outflow into Niagara River will be above average for November and forecasts say Lake Ontario’s outflow through St. Lawrence River will be above average in November.

ALERTS

Water levels shown are still-water surface elevations over the entire lake surface. Water levels at specific locations may differ substantially due to meteorological influences. Official records are based on monthly average water levels and not daily water levels. Great Lakes, connecting channels and St. Lawrence River users should keep informed of current conditions before undertaking any activities affected by changing water levels. Mariners should utilize navigation charts and refer to current water level readings.

SUPERIOR

MICH-HURON

ST. CLAIR

ERIE

ONTARIO

Forecasted Water Level for Nov 26, 2021 (feet)

601.51

579.86

575.56

572.80

245.67

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+5

+28

+39

+43

+28

Difference from average water level for Oct 26, 2021 (inches*)

-4

-5

-9

-4

+4

Difference from average water level for Nov 26, 2020 (inches*)

-14

-18

-9

-2

+11

Difference from long-term monthly average of Nov (inches)

-6

+13

+20

+22

+13

Difference from highest monthly average of record for Nov (inches)

-22

-25

-15

-10

-12

Year of highest recorded monthly mean

1985

1986

1986

1986

1945

Difference from lowest monthly average of record for Nov (inches)

+13

+43

+49

+55

+44

Year of lowest recorded monthly mean

1925

1964

1934

1934

1934

Projected net change in levels by Dec 26, 2021 (inches)

-2

-2

-2

-2

-3

ALL DATA SHOWN IN THIS SUMMARY ARE REFERENCED TO IGLD 1985

*VALUES FOR SPECIFIC DAY ARE BASED ON 3-DAY DAILY AVERAGE AROUND SPECIFIED DATE

LONG TERM AVERAGE PERIOD OF RECORD, 1918-2020

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

Department of the Army

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Detroit District Great Lakes Homepage

Detroit District, Corps of Engineers

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Weekly Great Lakes Water Levels

We do not have the ability to offer email updates at this time.  The Weekly Forecast of Great Lakes Water Levels is updated each week on Thursday afternoon or Friday morning depending on data availability.

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Detroit District Disclaimer

NOTICE: All data contained herein is preliminary in nature and therefore subject to change. The data is for general information purposes ONLY and SHALL NOT be used in technical applications such as, but not limited to, studies or designs. All critical data should be obtained from and verified by the United States Army Corps of Engineers, Detroit District, Engineering and Construction Division, Hydraulics and Hydrology Branch, 477 Michigan Ave., Detroit, MI 48226. The United States of America assumes no liability for the completeness or accuracy of the data contained herein and any use of such data inconsistent with this disclaimer shall be solely at the risk of the user.