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Great Lakes Water Level Outlook - July 2019 Edition - Update September 2019

Outlook Summary:

This product is not an official forecast of Great Lakes water levels. Rather, this product is meant to illustrate outcomes that would occur under historical weather and water supply condition, with scenarios chosen based on similarities to recent conditions. For the official forecast, please see our Monthly Bulletin of Great Lakes Water Levels.

 

Monthly mean water levels set new August monthly records on Lakes St. Clair and Erie, while Lake Superior matched its record high August mean level. These record high water levels have been a result of persistent wet conditions that have existed over the past several months to years, with recent high precipitation and runoff in the spring causing substantial rises in lake levels across the basin. During the spring, the lakes tend to rise due to increased precipitation and increased runoff as result of snowmelt. In the fall, the lakes generally decline due to an increase in evaporation as temperatures cool off and the cold air moves over the relatively warm lake waters. We refer to the combined effect of precipitation over the lake, evaporation from the lake, and runoff to the lake as Net Basin Supply (NBS). This edition of the Water Level Outlook incorporates the projection of water levels if the cumulative NBS over the next 12 months remains high or if the cumulative NBS is low. The two green lines represent scenarios that are characterized by high cumulative NBS over the next 12 months (July to June). The two blue lines represent scenarios that are characterized by very low cumulative NBS over the next 12 months (July to June). The most recent coordinated 6-month forecast is also shown for comparison.



Click on the individual graphics to view a larger, printer-friendly image (pdf).




 




 
* For the official 6-month forecast of all lakes, including Lake Ontario, see the Monthly Bulletin of Great Lakes Water Levels.
 

 

Click here to obtain the full Great Lakes Water Level Outlook document (pdf)

Great Lakes Water Level Outlook Data

 

To view the water level outlook data in tabular format, click on the links below.

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Lake Superior

Monthly Mean Water Level (meters IGLD)

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 183.85 183.81 183.74 183.67 183.58 183.51 183.50 183.55 183.64 183.73 183.79 183.84
1992-93 183.86 183.86 183.81 183.77 183.71 183.60 183.52 183.54 183.66 183.76 183.83 183.88
1998-99 183.79 183.70 183.63 183.56 183.47 183.42 183.38 183.39 183.49 183.57 183.66 183.70
1976-77 183.78 183.66 183.54 183.42 183.33 183.28 183.30 183.37 183.41 183.45 183.51 183.56
Ensemble Median 183.83 183.78 183.73 183.66 183.57 183.50 183.46 183.48 183.57 183.65 183.71 183.73
Long Term Average 183.54 183.51 183.47 183.41 183.33 183.27 183.23 183.26 183.36 183.45 183.51 183.54
Long Term Maximum 183.86 183.91 183.89 183.81 183.70 183.63 183.61 183.68 183.74 183.76 183.82 183.86
Long Term Minimum 183.02 183.10 183.01 182.92 182.83 182.76 182.74 182.72 182.76 182.85 182.96 183.01

 

 

Lake Michigan-Huron

Monthly Mean Water Level (meters IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 177.24 177.19 177.13 177.10 177.10 177.09 177.13 177.24 177.36 177.46 177.48 177.45
1992-93 177.25 177.21 177.22 177.24 177.21 177.19 177.15 177.22 177.33 177.41 177.48 177.47
1998-99 177.20 177.08 176.97 176.88 176.82 176.81 176.78 176.78 176.82 176.86 176.90 176.86
1976-77 177.20 177.06 176.93 176.81 176.68 176.62 176.69 176.78 176.80 176.78 176.78 176.77
Ensemble Median 177.23 177.15 177.08 177.02 176.96 176.94 176.96 177.02 177.09 177.14 177.15 177.13
Long Term Average 176.51 176.44 176.39 176.34 176.30 176.28 176.30 176.39 176.48 176.55 176.58 176.56
Long Term Maximum 177.38 177.50 177.38 177.26 177.18 177.11 177.12 177.23 177.28 177.33 177.39 177.39
Long Term Minimum 175.76 175.70 175.65 175.61 175.57 175.59 175.58 175.61 175.74 175.76 175.78 175.77

 

 

Lake St. Clair

Monthly Mean Water Level (meters IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 175.78 175.71 175.69 175.73 175.74 175.67 175.84 175.90 175.93 175.99 175.97 175.91
1992-93 175.86 175.78 175.83 175.83 175.88 175.82 175.85 175.94 175.92 175.94 175.95 175.87
1998-99 175.73 175.58 175.44 175.36 175.40 175.39 175.38 175.43 175.45 175.46 175.44 175.37
1976-77 175.75 175.62 175.48 175.38 175.41 175.32 175.46 175.54 175.54 175.49 175.47 175.44
Ensemble Median 175.76 175.64 175.57 175.55 175.53 175.52 175.58 175.65 175.70 175.71 175.69 175.66
Long Term Average 175.10 175.00 174.92 174.92 174.85 174.79 174.91 175.05 175.13 175.18 175.20 175.16
Long Term Maximum 175.84 175.96 175.82 175.80 175.80 175.80 175.80 175.82 175.83 175.92 175.93 175.90
Long Term Minimum 174.34 174.27 174.18 174.24 173.88 173.89 174.05 174.32 174.42 174.45 174.50 174.41

 

 

Lake Erie

Monthly Mean Water Level (meters IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 174.92 174.82 174.79 174.87 174.90 174.84 174.95 175.10 175.10 175.13 175.11 175.01
1992-93 174.95 174.90 174.90 174.95 175.01 175.01 175.05 175.16 175.12 175.08 175.04 174.92
1998-99 174.84 174.66 174.50 174.40 174.44 174.49 174.51 174.59 174.63 174.59 174.55 174.46
1976-77 174.88 174.75 174.59 174.49 174.45 174.45 174.57 174.76 174.80 174.74 174.70 174.67
Ensemble Median 174.87 174.72 174.63 174.61 174.63 174.63 174.70 174.79 174.85 174.85 174.82 174.74
Long Term Average 174.18 174.08 174.01 174.00 174.00 174.00 174.08 174.23 174.31 174.35 174.33 174.27
Long Term Maximum 174.83 174.94 174.85 174.89 174.86 174.78 174.88 174.98 174.97 175.04 175.03 174.94
Long Term Minimum 173.38 173.30 173.20 173.19 173.21 173.18 173.20 173.38 173.44 173.45 173.45 173.43

 

Lake Superior

Monthly Mean Water Level (ft IGLD)

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 603.17 603.04 602.81 602.58 602.29 602.05 602.05 602.20 602.48 602.80 602.99 603.16
1992-93 603.22 603.22 603.06 602.92 602.73 602.38 602.09 602.17 602.55 602.88 603.12 603.30
1998-99 602.99 602.68 602.45 602.23 601.95 601.77 601.64 601.67 601.99 602.27 602.54 602.69
1976-77 602.94 602.55 602.18 601.79 601.49 601.32 601.38 601.60 601.74 601.86 602.06 602.24
Ensemble Median 603.10 602.97 602.80 602.55 602.25 602.04 601.91 601.97 602.27 602.54 602.73 602.79
Long Term Average 602.17 602.07 601.94 601.74 601.48 601.28 601.15 601.25 601.57 601.87 602.07 602.17
Long Term Maximum 603.22 603.38 603.31 603.05 602.69 602.46 602.40 602.62 602.82 602.89 603.08 603.22
Long Term Minimum 600.46 600.72 600.43 600.13 599.84 599.61 599.54 599.48 599.61 599.90 600.26 600.43

 

 

Lake Michigan-Huron

Monthly Mean Water Level (ft IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 581.51 581.34 581.15 581.05 581.04 580.99 581.14 581.51 581.90 582.23 582.28 582.20
1992-93 581.53 581.41 581.44 581.49 581.40 581.34 581.21 581.43 581.78 582.07 582.28 582.24
1998-99 581.37 580.97 580.62 580.31 580.12 580.10 579.99 579.99 580.13 580.26 580.39 580.26
1976-77 581.35 580.89 580.49 580.08 579.65 579.48 579.68 579.99 580.06 579.99 579.98 579.97
Ensemble Median 581.45 581.19 580.97 580.77 580.59 580.53 580.59 580.78 580.99 581.15 581.21 581.14
Long Term Average 579.10 578.87 578.71 578.54 578.41 578.35 578.41 578.71 579.00 579.23 579.33 579.27
Long Term Maximum 581.96 582.35 581.96 581.56 581.30 581.07 581.10 581.46 581.63 581.79 581.99 581.99
Long Term Minimum 576.64 576.44 576.28 576.15 576.02 576.08 576.05 576.15 576.57 576.64 576.71 576.67

 

 

Lake St. Clair

Monthly Mean Water Level (ft IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 576.69 576.46 576.40 576.54 576.58 576.35 576.92 577.10 577.20 577.39 577.35 577.12
1992-93 576.95 576.72 576.87 576.85 577.05 576.84 576.95 577.24 577.18 577.24 577.25 577.02
1998-99 576.56 576.04 575.61 575.33 575.47 575.43 575.41 575.56 575.63 575.65 575.59 575.37
1976-77 576.60 576.17 575.72 575.38 575.48 575.20 575.67 575.93 575.92 575.75 575.69 575.59
Ensemble Median 576.63 576.26 576.00 575.94 575.89 575.86 576.06 576.29 576.45 576.47 576.42 576.30
Long Term Average 574.48 574.15 573.88 573.88 573.65 573.46 573.85 574.31 574.57 574.74 574.80 574.67
Long Term Maximum 576.90 577.30 576.84 576.77 576.77 576.77 576.77 576.84 576.87 577.17 577.20 577.10
Long Term Minimum 571.98 571.75 571.46 571.65 570.47 570.51 571.03 571.92 572.24 572.34 572.51 572.21

 

 

Lake Erie

Monthly Mean Water Level (ft IGLD)

 

  Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20
1972-73 573.87 573.56 573.47 573.73 573.82 573.63 573.97 574.47 574.49 574.57 574.51 574.17
1992-93 573.98 573.83 573.82 573.98 574.18 574.20 574.31 574.66 574.54 574.40 574.27 573.89
1998-99 573.62 573.02 572.50 572.18 572.29 572.46 572.52 572.82 572.95 572.81 572.66 572.36
1976-77 573.77 573.34 572.80 572.47 572.35 572.33 572.74 573.37 573.50 573.30 573.16 573.07
Ensemble Median 573.70 573.24 572.93 572.85 572.93 572.92 573.15 573.45 573.65 573.67 573.54 573.30
Long Term Average 571.46 571.13 570.90 570.87 570.87 570.87 571.13 571.62 571.88 572.01 571.95 571.75
Long Term Maximum 573.59 573.95 573.65 573.79 573.69 573.43 573.75 574.08 574.05 574.28 574.25 573.95
Long Term Minimum 568.83 568.57 568.24 568.21 568.27 568.18 568.24 568.83 569.03 569.06 569.06 569.00

 

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.