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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

Sep 21, 2018

 

WEATHER CONDITIONS

Over the final official week of summer, temperatures remained 4-8 °C above average over the Great Lakes basin.  Southeast regions of the basin, including Ohio, Pennsylvania and New York, received some rainfall early in the week, as a result of Hurricane Florence.  In the coming weekend, a high pressure system is expected to pass over the Great Lakes basin.  As a result, cities such as Chicago, IL, Duluth, MN and Marquette, MI, are expecting some sunny weather, following the rainfall from the end of the week.  In early next week, cities like Cleveland, OH, Buffalo and Binghamton, NY are expecting a chance of showers.  

LAKE LEVEL CONDITIONS

All of the Great Lakes water levels, except Ontario, are currently above their September long-term average water levels, and Lakes Michigan-Huron, St. Clair and Erie are above last year’s levels by 1, 2 and 4 inches, respectively. Like last week, Lake Superior is below last year’s level by 4 inches, and Lake Ontario is 13 inches below its level from a year ago. In the last month, Lake Michigan-Huron maintained a consistent water level, while Lake Superior rose 2 inches, and Lakes St. Clair, Erie, and Ontario, declined by 1, 2, and 7 inches, respectively. In the next month, levels are forecasted to decline on all the lakes. Lakes Superior, Michigan-Huron, St. Clair, Erie, and Ontario are forecasted to fall by 2, 3, 6, 6, and 5 inches, respectively. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

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

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 Sep 21, 2018 (feet)

602.69

580.51

576.18

573.06

245.11

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+19

+36

+47

+46

+22

Difference from average water level for Aug 21, 2018 (inches*)

+2

0

-1

-2

-7

Difference from average water level for Sep 21, 2017 (inches*)

-4

+1

+2

+4

-13

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

+6

+17

+21

+20

-1

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

-6

-17

-9

-6

-28

Year of highest recorded monthly mean

1985

1986

1986

1986

1947

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

27

46

50

51

31

Year of lowest recorded monthly mean

2007

1964

1934

1934

1934

Projected change in levels by Oct 21, 2018 (inches)

-2

-3

-6

-6

-5

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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