ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

May 26, 2023

WEATHER CONDITIONS

Over the past week, air temperatures in the Great Lakes basin were near to above average before turning cool near the end of this week. Precipitation was much below average over the past week with most of the basin receiving 0-50% of average with isolated pockets of an inch falling over the eastern Upper Peninsula of Michigan and Lakes Erie and Ontario basins. Heading into the weekend, a high-pressure system will settle over the Great Lakes region bringing dry and sunny conditions. Air temperatures are forecast to rise back to seasonable and warm to above average through next week. Forecasts show dry conditions to remain across the whole basin early into next week.

LAKE LEVEL CONDITIONS

Projected water levels for May 26^th for Lakes Superior, Michigan-Huron, St Clair, and Ontario are 3 to 6 inches above what they were a month ago, and Erie is near its level of a month ago. Forecasted water levels for May 26^th for Lakes Superior and Ontario are 7 to 8 inches above their levels of a year ago, while Lakes Michigan-Huron, Lake Erie, and Lake St Clair are 1 to 3 inches below what they were a year ago. In addition, forecasted water levels for May 26^th across all the lakes are above their May long-term average levels. Over the next 30 days, Lakes Superior and Michigan-Huron are expected to rise 3 and 2 inches, respectively. Lake St. Clair is forecast to remain near its current level and Lakes Erie and Ontario are predicted to decline 1 and 5 inches, respectively, by June 26^th. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Lake Superior’s outflow through St. Marys River and Lake Michigan-Huron’s outflow through St. Clair River are forecasted to be above average for May. Lake St. Clair outflow through Detroit River, Lake Erie outflow through Niagara River, and Lake Ontario outflow through the St. Lawrence River are projected to be above average in May as well.

ALERTS

Water levels shown are still-water surface elevations over the entire lake surface. Water levels at specific locations may differ due to meteorological influences. Official records are based on monthly average water levels and not daily water levels. Great Lakes, connecting channels, and St. Lawrence River users should keep informed of current conditions before undertaking any activities affected by changing water levels. Mariners should use navigation charts and refer to current water level readings. Find ice information at National Ice Center’s website.

SUPERIOR

MICH-HURON

ST. CLAIR

ERIE

ONTARIO

Forecasted Water Level for May 26, 2023 (feet)

602.69

579.72

575.72

573.00

247.24

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+19

+27

+41

+46

+47

Difference from average water level for Apr 26, 2023 (inches*)

+6

+4

+3

0

+6

Difference from average water level for May 26, 2022 (inches*)

+7

-3

-1

-1

+8

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

+13

+7

+13

+13

+13

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

-3

-26

-20

-17

-17

Year of highest recorded monthly mean

2019

2020

2020

2020

2017

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

+37

+38

+42

+48

+49

Year of lowest recorded monthly mean

1926

1964

1934

1934

1935

Projected net change in levels by Jun 26, 2023 (inches)

+3

+2

0

-1

-5

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, 1918-2022

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

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