ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

Jun 18, 2021

WEATHER CONDITIONS

The entire basin experienced a return to normal temperatures from the well above average temperatures experienced the week prior. Almost all the basin received some amount of precipitation over the past week. Month to date, the Great Lakes Basin has received less than average precipitation, averaging 57% or normal. Chicago and most of the lower peninsula of Michigan are still experiencing a moderate to severe drought due to persistent dry conditions over the past several months. There is a chance of rain and thunderstorms across the entirety of the basin heading into the weekend. Above average temperatures are forecasted to return for most of the basin this weekend as well.

LAKE LEVEL CONDITIONS

The projected levels for June 18^th indicate that all the lakes are within 3 inches of the levels from one month ago and all are below levels from this time last year. The forecasted June 18^th water levels also show that water levels are above their long-term monthly averages for June, and below their record high monthly averages for June on all lakes, except Lake Ontario. Lake Ontario’s forecasted June 18^th level is below its long-term average June level. Lakes Superior and Ontario are forecast to rise 1 and 2 inches, respectively, by July 18^th. Lakes Michigan-Huron are forecast to be near their current respective levels one month from now and Lakes Erie and St. Clair are forecast to decline 2 inches by July 18^th. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Lake Superior’s outflow through the St. Marys River is predicted to be average this June. Lake Michigan-Huron’s outflow through the St. Clair River and Lake St. Clair’s outflow into the Detroit River are forecasted to be above average for June. Lake Erie’s outflow into the Niagara River is predicted to be above average for June and Lake Ontario’s outflow through the St. Lawrence River is projected to be above average in June.

ALERTS

Water levels shown are still-water surface elevations over the entire lake surface. Water levels at specific locations may differ substantially due to meteorological influences. 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 Jun 18, 2021 (feet)

602.26

580.48

576.21

573.20

245.11

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+14

+36

+47

+48

+22

Difference from average water level for May 18, 2021 (inches*)

+3

0

+3

+1

-1

Difference from average water level for Jun 18, 2020 (inches*)

-5

-20

-15

-15

-22

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

+5

+14

+17

+14

-14

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

-11

-20

-15

-17

-47

Year of highest recorded monthly mean

2019

2020

2020

2019

2019

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

+28

+46

+46

+50

+20

Year of lowest recorded monthly mean

1926

1964

1934

1934

1935

Projected net change in levels by Jul 18, 2021 (inches)

+1

0

-2

-2

+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, 1918-2020

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

Department of the Army

provided by

Detroit District Great Lakes Homepage

Detroit District, Corps of Engineers

NOAA Center for Operational Oceanic Products and Services

International Joint Commission

Detroit District Home

1-888-694-8313 ext. 1

Great Lakes Information Network