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Weekly Great Lakes Water Levels

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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 Technical Services, Great Lakes Hydraulics and Hydrology Office, 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.

Weekly Forecast

ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

Nov 16, 2018

 

WEATHER CONDITIONS

A dry second week of November across the Great Lakes basin has helped offset the wet start to the month. Even with below average precipitation last week the basin as a whole still has received 25% more than average month to date precipitation. The dry weather has been accompanied by much colder weather than normal with temperatures remaining between 10 and 20 degrees below their seasonal normal across the basin. The relatively dry weather is expected to continue for the next week with the exception of the Lake Erie and Ontario basins which should see between 0.5 and 1.0 inches of precipitation in the next week. The colder than average weather should continue through the weekend before a gradual warming trend should see most areas back to seasonally normal temperatures by Thursday.

LAKE LEVEL CONDITIONS

Lake Superior’s water declined an inch over the last month as Lake Michigan-Huron declined 2 inches. Lakes St. Clair and Erie rose 1 and 2 inches respectively, due in part to the early November rainfall. Lake Ontario continued its seasonal decline with a drop of 1 inch over the last month. When compared to their levels a year ago, Lakes Superior, Michigan-Huron, St. Clair, and Erie are all higher with respective differences of 1, 1, 5, and 5 inches greater than this time a year ago. Lake Ontario is 10 inches below its level at this time last year. The water level forecast calls for all of the Lakes to decline with Lakes Superior and Michigan-Huron both declining 2 inches. Lake St. Clair is expected to decline 3 inches while Lakes Erie and Ontario are both expected to decline 2 inches over the next month. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Lake Superior’s outflow through the St. Mary’s River is predicted to be above average in November. Lake Michigan-Huron’s outflow into the St. Clair River and the outflow of Lake St. Clair through the Detroit River are projected to be above average. Moreover, Lake Erie’s outflow through the Niagara River and the outflow of Lake Ontario through the St. Lawrence River are forecasted to be above average for November.

ALERTS

Official records are based on monthly average water levels and not daily water levels. Users of the Great Lakes, connecting channels and St. Lawrence River should keep informed of current conditions before undertaking any activities that could be 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 16, 2018 (feet)

602.99

580.28

575.82

572.80

244.82

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+23

+33

+42

+43

+18

Difference from average water level for Oct 16, 2018 (inches*)

-1

-2

+1

+2

-1

Difference from average water level for Nov 16, 2017 (inches*)

+1

+1

+5

+5

-10

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

+13

+19

+24

+23

+3

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

-4

-20

-12

-10

-22

Year of highest recorded monthly mean

1985

1986

1986

1986

1945

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

31

48

52

55

34

Year of lowest recorded monthly mean

1925

1964

1934

1934

1934

Projected change in levels by Dec 16, 2018 (inches)

-2

-2

-3

-2

-2

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, 1918-2017

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

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