Great Lakes Water Level Outlook - April 2018 Edition

Outlook Summary:

As of April 1st, all of the Great Lakes continue to experience water levels above their long-term average (LTA). The net basin supplies for the Great Lakes during March were well below average as a result of minimal precipitation throughout the basin. The Lake Superior basin experienced its second driest March on record with just 0.46 inches of precipitation during the month. Net Basin Supply (NBS) is the combined effect of precipitation over the lake, evaporation from the lake, and runoff to the lake. Prior years with low March NBS show the potential to be followed by both high and low NBS during the spring and early summer. This edition of the Water Level Outlook incorporates the projection of water levels if NBS values are similar to those seen during previous years when a low March NBS occurred, followed by a dry or wet April to June. The lines are broken into two groups by color. The green lines represent water levels that would occur if low March NBS was followed by high NBS in April through June. The brown lines represent water levels that would occur if low March NBS is followed by low NBS in the April through June timeframe. The most recent coordinated 6-month forecast is also shown for comparison.

 

 





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* At this time, water level outlooks for Lake Ontario are still under development due to complexities of its weekly regulation process.






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)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 183.53 183.58 183.60 183.58 183.53 183.49 183.43 183.32 183.27 183.26 183.29 183.36
1969 183.53 183.57 183.61 183.60 183.54 183.48 183.40 183.33 183.28 183.24 183.27 183.41
1996 183.57 183.68 183.75 183.76 183.75 183.71 183.65 183.60 183.55 183.51 183.57 183.66
1900 183.51 183.57 183.70 183.84 183.88 183.81 183.70 183.59 183.49 183.44 183.45 183.50
1931 183.54 183.59 183.58 183.57 183.57 183.56 183.52 183.44 183.38 183.33 183.32 183.41
1958 183.55 183.63 183.67 183.67 183.63 183.58 183.51 183.40 183.33 183.28 183.28 183.39
Ensemble Median 183.55 183.61 183.63 183.63 183.62 183.56 183.48 183.40 183.34 183.31 183.35 183.43
Long Term Average 183.45 183.51 183.54 183.54 183.51 183.47 183.40 183.33 183.26 183.23 183.26 183.36
Long Term Maximum 183.76 183.82 183.86 183.86 183.91 183.89 183.81 183.70 183.63 183.61 183.68 183.74
Long Term Minimum 182.85 182.96 183.01 183.02 183.10 183.01 182.92 182.83 182.76 182.74 182.72 182.76

Lake Michigan-Huron

Monthly Mean Water Level (meters IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 176.99 177.05 177.05 176.99 176.89 176.80 176.71 176.60 176.53 176.53 176.57 176.60
1969 177.01 177.08 177.06 176.96 176.86 176.81 176.74 176.67 176.61 176.58 176.62 176.71
1996 177.01 177.08 177.07 177.05 177.02 176.96 176.94 176.96 177.01 177.06 177.11 177.20
1900 176.96 177.00 177.04 177.03 177.01 176.98 176.90 176.81 176.75 176.78 176.85 176.91
1931 176.96 176.94 176.85 176.81 176.77 176.73 176.68 176.66 176.68 176.64 176.64 176.68
1958 176.95 176.96 176.93 176.87 176.80 176.69 176.59 176.51 176.48 176.50 176.59 176.72
Ensemble Median 176.97 177.00 176.97 176.92 176.84 176.76 176.72 176.67 176.64 176.64 176.71 176.79
Long Term Average 176.55 176.58 176.56 176.51 176.44 176.38 176.33 176.30 176.28 176.30 176.38 176.48
Long Term Maximum 177.33 177.39 177.39 177.38 177.50 177.38 177.26 177.18 177.11 177.12 177.23 177.28
Long Term Minimum 175.76 175.78 175.77 175.76 175.70 175.65 175.61 175.57 175.59 175.58 175.61 175.74

Lake St. Clair

Monthly Mean Water Level (meters IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 175.69 175.65 175.60 175.51 175.37 175.26 175.20 175.09 175.10 175.18 175.34 175.41
1969 175.68 175.72 175.66 175.52 175.40 175.35 175.31 175.24 175.20 175.26 175.35 175.40
1996 175.74 175.73 175.66 175.65 175.60 175.54 175.59 175.63 175.71 175.80 175.79 175.86
1900 175.63 175.59 175.57 175.50 175.41 175.37 175.31 175.26 175.28 175.28 175.30 175.35
1931 175.62 175.57 175.47 175.39 175.33 175.26 175.27 175.28 175.35 175.28 175.29 175.38
1958 175.65 175.64 175.58 175.51 175.41 175.27 175.23 175.16 175.20 175.34 175.43 175.49
Ensemble Median 175.65 175.62 175.55 175.46 175.38 175.32 175.30 175.26 175.28 175.34 175.42 175.46
Long Term Average 175.18 175.20 175.16 175.09 175.00 174.91 174.91 174.84 174.79 174.90 175.04 175.13
Long Term Maximum 175.92 175.93 175.90 175.84 175.96 175.82 175.80 175.80 175.80 175.80 175.82 175.83
Long Term Minimum 174.45 174.50 174.41 174.34 174.27 174.18 174.24 173.88 173.89 174.05 174.32 174.42

Lake Erie

Monthly Mean Water Level (meters IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 174.89 174.84 174.74 174.61 174.43 174.31 174.23 174.16 174.19 174.32 174.54 174.68
1969 174.90 174.93 174.85 174.68 174.52 174.43 174.43 174.38 174.36 174.42 174.53 174.61
1996 174.94 174.94 174.82 174.75 174.69 174.63 174.70 174.74 174.82 174.97 174.99 175.04
1900 174.85 174.76 174.68 174.56 174.42 174.36 174.33 174.30 174.24 174.28 174.42 174.48
1931 174.86 174.77 174.65 174.52 174.41 174.34 174.36 174.47 174.54 174.52 174.52 174.57
1958 174.88 174.85 174.78 174.68 174.54 174.42 174.34 174.35 174.45 174.56 174.68 174.74
Ensemble Median 174.87 174.80 174.70 174.58 174.47 174.39 174.38 174.40 174.42 174.48 174.58 174.66
Long Term Average 174.34 174.33 174.26 174.17 174.07 174.00 173.99 174.00 173.99 174.08 174.23 174.31
Long Term Maximum 175.04 175.03 174.94 174.83 174.94 174.85 174.89 174.86 174.78 174.88 174.98 174.97
Long Term Minimum 173.45 173.45 173.43 173.38 173.30 173.20 173.19 173.21 173.18 173.20 173.38 173.44

Lake Superior

Monthly Mean Water Level (ft IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 602.15 602.29 602.36 602.31 602.14 602.01 601.79 601.45 601.29 601.25 601.34 601.58
1969 602.14 602.28 602.40 602.37 602.18 601.98 601.71 601.48 601.32 601.17 601.27 601.74
1996 602.25 602.61 602.84 602.89 602.86 602.74 602.51 602.37 602.20 602.07 602.26 602.55
1900 602.08 602.27 602.67 603.14 603.29 603.05 602.69 602.32 602.01 601.84 601.87 602.02
1931 602.16 602.31 602.30 602.25 602.25 602.23 602.11 601.85 601.65 601.49 601.46 601.73
1958 602.20 602.46 602.59 602.59 602.47 602.30 602.05 601.72 601.47 601.32 601.33 601.66
Ensemble Median 602.19 602.38 602.46 602.46 602.41 602.24 601.98 601.72 601.51 601.40 601.53 601.81
Long Term Average 601.87 602.07 602.17 602.17 602.07 601.94 601.71 601.48 601.25 601.15 601.25 601.57
Long Term Maximum 602.89 603.08 603.22 603.22 603.38 603.31 603.05 602.69 602.46 602.40 602.62 602.82
Long Term Minimum 599.90 600.26 600.43 600.46 600.72 600.43 600.13 599.84 599.61 599.54 599.48 599.61

Lake Michigan-Huron

Monthly Mean Water Level (ft IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 580.68 580.87 580.88 580.68 580.34 580.04 579.75 579.38 579.18 579.18 579.30 579.41
1969 580.73 580.98 580.92 580.57 580.25 580.08 579.84 579.61 579.44 579.32 579.47 579.77
1996 580.75 580.98 580.94 580.86 580.78 580.59 580.52 580.58 580.73 580.89 581.08 581.37
1900 580.57 580.72 580.85 580.82 580.75 580.66 580.38 580.08 579.88 579.98 580.22 580.40
1931 580.56 580.50 580.23 580.07 579.95 579.81 579.66 579.58 579.64 579.54 579.52 579.67
1958 580.55 580.58 580.48 580.29 580.04 579.70 579.36 579.10 579.01 579.05 579.38 579.79
Ensemble Median 580.62 580.70 580.61 580.43 580.18 579.91 579.77 579.61 579.52 579.54 579.75 580.03
Long Term Average 579.23 579.33 579.27 579.10 578.87 578.67 578.51 578.41 578.35 578.41 578.67 579.00
Long Term Maximum 581.79 581.99 581.99 581.96 582.35 581.96 581.56 581.30 581.07 581.10 581.46 581.63
Long Term Minimum 576.64 576.71 576.67 576.64 576.44 576.28 576.15 576.02 576.08 576.05 576.15 576.57

Lake St. Clair

Monthly Mean Water Level (ft IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 576.40 576.28 576.13 575.82 575.37 575.01 574.81 574.44 574.47 574.74 575.25 575.49
1969 576.39 576.50 576.33 575.86 575.47 575.30 575.18 574.93 574.81 574.99 575.29 575.44
1996 576.57 576.55 576.31 576.27 576.12 575.92 576.10 576.22 576.47 576.78 576.75 576.98
1900 576.22 576.10 576.03 575.77 575.51 575.37 575.17 575.00 575.07 575.08 575.13 575.29
1931 576.20 576.02 575.68 575.44 575.22 575.00 575.03 575.05 575.28 575.07 575.10 575.41
1958 576.28 576.23 576.06 575.82 575.48 575.02 574.91 574.66 574.80 575.28 575.55 575.75
Ensemble Median 576.29 576.18 575.96 575.67 575.39 575.19 575.13 575.01 575.06 575.27 575.53 575.66
Long Term Average 574.74 574.80 574.67 574.44 574.15 573.85 573.85 573.62 573.46 573.82 574.28 574.57
Long Term Maximum 577.17 577.20 577.10 576.90 577.30 576.84 576.77 576.77 576.77 576.77 576.84 576.87
Long Term Minimum 572.34 572.51 572.21 571.98 571.75 571.46 571.65 570.47 570.51 571.03 571.92 572.24

Lake Erie

Monthly Mean Water Level (ft IGLD)
Jun-18 Jul-18 Aug-18 Sep-18 Oct-18 Nov-18 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19
1960 573.80 573.61 573.30 572.87 572.28 571.87 571.63 571.41 571.49 571.91 572.65 573.09
1969 573.82 573.90 573.66 573.11 572.56 572.29 572.28 572.12 572.05 572.25 572.61 572.86
1996 573.96 573.96 573.55 573.34 573.14 572.93 573.16 573.30 573.56 574.05 574.11 574.28
1900 573.65 573.35 573.08 572.70 572.26 572.05 571.94 571.83 571.64 571.79 572.24 572.44
1931 573.69 573.41 573.00 572.58 572.23 571.97 572.04 572.41 572.63 572.56 572.57 572.74
1958 573.76 573.65 573.43 573.10 572.65 572.24 571.99 572.03 572.33 572.70 573.10 573.30
Ensemble Median 573.72 573.47 573.15 572.78 572.40 572.15 572.11 572.18 572.26 572.44 572.76 573.03
Long Term Average 571.98 571.95 571.72 571.42 571.10 570.87 570.83 570.87 570.83 571.13 571.62 571.88
Long Term Maximum 574.28 574.25 573.95 573.59 573.95 573.65 573.79 573.69 573.43 573.75 574.08 574.05
Long Term Minimum 569.06 569.06 569.00 568.83 568.57 568.24 568.21 568.27 568.18 568.24 568.83 569.03

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.