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Weekly Great Lakes Water Levels

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Weekly Forecast

WEEKLY GREAT LAKES WATER LEVEL UPDATE

July 25, 2014

 

WEATHER CONDITIONS

The Great Lakes Basin experienced slightly cooler than average temperatures this past weekend.  However, temperatures were moderate early in the workweek before dropping on Wednesday. The region was generally dry this past week, although significant rain fell in the Lake Superior basin on Wednesday. A rainy weekend, however, is predicted for the majority of the basin.  Temperatures will hover around average this weekend, but are expected to drop to below average by Monday.

LAKE LEVEL CONDITIONS

Lakes Superior and Michigan-Huron are 11 and 15 inches, respectively, above what they were at this time last year.   Lake St. Clair is 7 inches above its level of a year ago, Lake Erie is near the same level as it was a year ago, and Lake Ontario is 3 inches below its level of a year ago. Lakes Superior and Michigan-Huron are each predicted to climb an inch over the next month.  Lakes St. Clair, Erie and Ontario, are forecasted to drop 1, 3, and 7 inches, respectively during the next thirty days. 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 forecasted to be above average for the month of July.  Lake Michigan-Huron’s outflow into the St. Clair River and Lake St. Clair’s outflow into the Detroit River are predicted to be near average in July.  In addition, the outflow of Lake Erie into the Niagara River and Lake Ontario’s outflow into the St. Lawrence River are projected to be above average in July.

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 Jul 25, 2014 (feet)

602.62

578.97

575.07

572.18

246.23

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+18

+18

+33

+36

+35

Difference from average water level for Jun 25, 2014 (inches*)

+2

+2

+1

-1

-5

Difference from average water level for Jul 25, 2013 (inches*)

+11

+15

+7

0

-3

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

+7

-4

+4

+4

+2

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

-6

-36

-26

-25

-24

Year of highest recorded monthly mean

1950

1986

1986

1986

1947

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

+28

+27

+31

+37

+36

Year of lowest recorded monthly mean

1926

1964

1934

1934

1934

Projected change in levels by Aug 25, 2014 (inches)

+1

+1

-1

-3

-7

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, 1918-2013

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

Department of the Army

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Detroit District, Corps of Engineers

NOAA, Great Lakes Online

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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.