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Great Lakes Water Level Outlook - October 2019 Edition - Updated December 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.

 

Water levels across the Great Lakes remain well above average and near record high levels. 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. During the spring, the lakes tend to rise due to increased precipitation and increased runoff as result of snowmelt.  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 is a repeat of last year (high), near average, or a lower cumulative NBS scenario. The green line represents the 2018-19 scenario, which is characterized by high cumulative NBS over the next 12 months (Oct.-Sep.). The purple line represents the 1993-94 scenario, which is characterized by near average NBS throughout the next 12 months. The yellow line shows the 1998-99 scenario, which represents a lower cumulative NBS scenario that was also characterized by a transition from high to low water periods. 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)

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 183.74 183.66 183.63 183.63 183.68 183.81 183.88 183.91 183.90 183.91 183.93 183.86
1993-94 183.75 183.67 183.59 183.56 183.59 183.66 183.73 183.78 183.80 183.81 183.77 183.68
1998-99 183.74 183.65 183.59 183.54 183.54 183.63 183.71 183.79 183.83 183.78 183.72 183.62
Ensemble Median 183.73 183.64 183.57 183.53 183.55 183.63 183.72 183.77 183.79 183.79 183.76 183.70
Long Term Average 183.41 183.33 183.27 183.23 183.26 183.36 183.45 183.51 183.54 183.54 183.51 183.47
Long Term Maximum 183.81 183.70 183.63 183.61 183.68 183.74 183.76 183.82 183.86 183.86 183.91 183.89
Long Term Minimum 182.92 182.83 182.76 182.74 182.72 182.76 182.85 182.96 183.01 183.02 183.10 183.01

 

 

Lake Michigan-Huron

Monthly Mean Water Level (meters IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 177.25 177.22 177.21 177.24 177.36 177.55 177.69 177.74 177.70 177.66 177.66 177.65
1993-94 177.22 177.16 177.13 177.14 177.18 177.22 177.25 177.30 177.32 177.28 177.20 177.12
1998-99 177.20 177.14 177.12 177.09 177.09 177.12 177.16 177.19 177.15 177.05 176.93 176.81
Ensemble Median 177.22 177.17 177.14 177.14 177.19 177.27 177.31 177.32 177.30 177.25 177.17 177.12
Long Term Average 176.34 176.30 176.28 176.30 176.39 176.48 176.55 176.58 176.56 176.51 176.44 176.39
Long Term Maximum 177.26 177.18 177.11 177.12 177.23 177.28 177.33 177.39 177.39 177.38 177.50 177.38
Long Term Minimum 175.61 175.57 175.59 175.58 175.61 175.74 175.76 175.78 175.77 175.76 175.70 175.65

 

 

Lake St. Clair

Monthly Mean Water Level (meters IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 175.78 175.77 175.78 175.89 175.94 176.04 176.12 176.13 176.00 175.93 175.89 175.88
1993-94 175.65 175.63 175.62 175.70 175.77 175.79 175.80 175.81 175.79 175.72 175.63 175.54
1998-99 175.63 175.66 175.64 175.63 175.66 175.68 175.68 175.66 175.59 175.48 175.38 175.30
Ensemble Median 175.68 175.66 175.63 175.69 175.78 175.83 175.83 175.83 175.77 175.69 175.61 175.53
Long Term Average 174.92 174.85 174.79 174.91 175.05 175.13 175.18 175.20 175.16 175.10 175.00 174.92
Long Term Maximum 175.80 175.80 175.80 175.80 175.82 175.83 175.92 175.93 175.90 175.84 175.96 175.82
Long Term Minimum 174.24 173.88 173.89 174.05 174.32 174.42 174.45 174.50 174.41 174.34 174.27 174.18

 

 

Lake Erie

Monthly Mean Water Level (meters IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 174.71 174.75 174.81 174.89 175.01 175.14 175.22 175.22 175.09 174.94 174.83 174.78
1993-94 174.67 174.64 174.66 174.74 174.89 174.92 174.91 174.90 174.86 174.77 174.65 174.54
1998-99 174.66 174.67 174.71 174.72 174.80 174.83 174.78 174.73 174.63 174.51 174.41 174.35
Ensemble Median 174.70 174.70 174.71 174.78 174.90 174.97 174.97 174.91 174.84 174.73 174.62 174.56
Long Term Average 174.00 174.00 174.00 174.08 174.23 174.31 174.35 174.33 174.27 174.18 174.08 174.01
Long Term Maximum 174.89 174.86 174.78 174.88 174.98 174.97 175.04 175.03 174.94 174.83 174.94 174.85
Long Term Minimum 173.19 173.21 173.18 173.20 173.38 173.44 173.45 173.45 173.43 173.38 173.30 173.20

 

Lake Superior

Monthly Mean Water Level (ft IGLD)

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 602.82 602.57 602.46 602.45 602.63 603.04 603.30 603.39 603.36 603.39 603.43 603.23
1993-94 602.86 602.60 602.33 602.22 602.32 602.57 602.78 602.95 603.02 603.04 602.92 602.62
1998-99 602.81 602.52 602.32 602.16 602.17 602.47 602.73 602.98 603.10 602.97 602.76 602.44
Ensemble Median 602.80 602.51 602.27 602.13 602.20 602.47 602.74 602.91 602.99 602.98 602.88 602.70
Long Term Average 601.74 601.48 601.28 601.15 601.25 601.57 601.87 602.07 602.17 602.17 602.07 601.94
Long Term Maximum 603.05 602.69 602.46 602.40 602.62 602.82 602.89 603.08 603.22 603.22 603.38 603.31
Long Term Minimum 600.13 599.84 599.61 599.54 599.48 599.61 599.90 600.26 600.43 600.46 600.72 600.43

 

 

Lake Michigan-Huron

Monthly Mean Water Level (ft IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 581.52 581.43 581.41 581.50 581.89 582.52 582.99 583.15 582.99 582.86 582.87 582.83
1993-94 581.43 581.22 581.14 581.17 581.30 581.42 581.52 581.68 581.75 581.62 581.36 581.11
1998-99 581.36 581.15 581.11 581.00 580.99 581.11 581.23 581.34 581.21 580.87 580.47 580.08
Ensemble Median 581.44 581.27 581.17 581.17 581.35 581.59 581.73 581.76 581.70 581.52 581.28 581.09
Long Term Average 578.54 578.41 578.35 578.41 578.71 579.00 579.23 579.33 579.27 579.10 578.87 578.71
Long Term Maximum 581.56 581.30 581.07 581.10 581.46 581.63 581.79 581.99 581.99 581.96 582.35 581.96
Long Term Minimum 576.15 576.02 576.08 576.05 576.15 576.57 576.64 576.71 576.67 576.64 576.44 576.28

 

 

Lake St. Clair

Monthly Mean Water Level (ft IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 576.70 576.68 576.70 577.06 577.21 577.55 577.82 577.84 577.44 577.20 577.05 577.02
1993-94 576.28 576.21 576.18 576.44 576.67 576.75 576.76 576.80 576.74 576.52 576.21 575.92
1998-99 576.23 576.31 576.24 576.20 576.33 576.39 576.38 576.31 576.07 575.71 575.39 575.13
Ensemble Median 576.39 576.30 576.22 576.42 576.72 576.86 576.88 576.87 576.68 576.41 576.16 575.87
Long Term Average 573.88 573.65 573.46 573.85 574.31 574.57 574.74 574.80 574.67 574.48 574.15 573.88
Long Term Maximum 576.77 576.77 576.77 576.77 576.84 576.87 577.17 577.20 577.10 576.90 577.30 576.84
Long Term Minimum 571.65 570.47 570.51 571.03 571.92 572.24 572.34 572.51 572.21 571.98 571.75 571.46

 

 

Lake Erie

Monthly Mean Water Level (ft IGLD)

 

  Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20
2018-19 573.21 573.33 573.52 573.77 574.18 574.59 574.88 574.87 574.43 573.96 573.58 573.41
1993-94 573.07 572.98 573.02 573.29 573.77 573.89 573.85 573.83 573.68 573.40 572.99 572.63
1998-99 573.02 573.07 573.20 573.22 573.48 573.58 573.43 573.26 572.95 572.54 572.20 572.01
Ensemble Median 573.16 573.16 573.20 573.43 573.81 574.05 574.05 573.86 573.63 573.26 572.92 572.70
Long Term Average 570.87 570.87 570.87 571.13 571.62 571.88 572.01 571.95 571.75 571.46 571.13 570.90
Long Term Maximum 573.79 573.69 573.43 573.75 574.08 574.05 574.28 574.25 573.95 573.59 573.95 573.65
Long Term Minimum 568.21 568.27 568.18 568.24 568.83 569.03 569.06 569.06 569.00 568.83 568.57 568.24

 

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.