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Weekly Great Lakes Water Levels

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Weekly Forecast

WEEKLY GREAT LAKES WATER LEVEL UPDATE

December 19, 2014

 

WEATHER CONDITIONS

 The Great Lakes experienced well above average temperatures over the last weekend and a general cooling towards average temperatures this week. The western portions of the Lake Superior basin received above average precipitation during the past week while the remainder of the basin saw below average precipitation.  Temperatures throughout the basin are expected to remain near normal during the weekend, and begin rising throughout the week to 10 to 15 degrees above normal by midweek. Above average precipitation is expected over the next 7 days with the majority of the precipitation being rain  during the middle of the workweek next week.

LAKE LEVEL CONDITIONS

Lakes Superior and Michigan-Huron are 9 and 21 inches, respectively, above their levels of a year ago. Lakes St. Clair and Erie are 11 and 10 inches, respectively, above what they were at this time last year, while, Lake Ontario is 2 inches below its level of a year ago.  Lakes Superior and Michigan-Huron are forecasted to fall 3 and 2 inches, respectively, over the next 30 days.  During the same time period, Lake St. Clair is projected to rise 1 inch, Lake Erie is expected to remain at its current level, and Lake Ontario is predicted to rise 2 inches. 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 December.  Lake Michigan-Huron’s outflow into the St. Clair River is predicted to be above average and Lake St. Clair’s outflow into the Detroit River is predicted to be above average in December.  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 December.

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 Dec 19, 2014 (feet)

602.33

579.07

574.34

571.33

244.29

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+15

+19

+24

+26

+12

Difference from average water level for Nov 19, 2014 (inches*)

-3

-1

+3

+3

+1

Difference from average water level for Dec 19, 2013 (inches*)

+9

+21

+11

+10

-2

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

+8

+7

+6

+6

-2

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

-9

-30

-29

-30

-29

Year of highest recorded monthly mean

1985

1986

1986

1986

1945

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

+26

+35

+32

+37

+28

Year of lowest recorded monthly mean

1925

2012

1964

1934

1934

Projected change in levels by Jan 19, 2015 (inches)

-3

-2

+1

0

+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, 1918-2013

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

NOAA, Great Lakes Online

International Joint Commission

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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.