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Weekly Forecast

ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

Jul 12, 2019

 

WEATHER CONDITIONS

This last week, temperatures throughout the Great Lakes Basin climbed towards above average values for this time of year, with temperatures expected to continue to rise through the weekend.  Some minor rainfall was experienced last week, but in general dry weather returned to the region. Expect drier than average conditions to continue through the weekend, with some potential for scattered precipitation. So far in July, precipitation has been below average throughout the Great Lakes Basin, with the exception of Lake Erie, which is just a bit above average. Temperatures are predicted to stay warm over the weekend, with a dip in temperature on Saturday in the Lake Superior Basin.

LAKE LEVEL CONDITIONS

Water levels remain high across the Great Lakes. The forecasted water level for July 12th indicates a decrease from last month of 1 inch on Lake Superior, and an increase of 3 and 4 inches on Lakes Michigan-Huron and St. Clair, respectively. There was no change on Lake Erie and Lake Ontario is expected to be 4 inches below its level a month ago. The forecasted level for July 12th either meets or exceeds the record high July monthly mean for all of the Great Lakes except Lake Michigan-Huron, which is 1 inch below. Lakes Superior and Michigan-Huron are projected to remain fairly steady by August 12th, while Lakes St. Clair, Erie and Ontario are expected to decline 3, 5, and 10 inches, respectively, over the next month. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Outflows from Lake Superior through the St. Mary’s River, and Lake Michigan-Huron’s outflow into the St. Clair River, are projected to be above average in July. Lake St. Clair’s outflow through the Detroit River is also forecasted to be above average. Similarly, Lake Erie’s outflow through the Niagara River and the Lake Ontario’s outflow through the St. Lawrence River are predicted to be above average for July.

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. High water levels and potentially record high water levels are expected to persist for at least the next six months, so flood prone areas are expected to remain vulnerable.

SUPERIOR

MICH-HURON

ST. CLAIR

ERIE

ONTARIO

Forecasted Water Level for Jul 12, 2019 (feet)

603.12

581.92

577.59

574.61

248.75

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+24

+53

+63

+65

+65

Difference from average water level for Jun 12, 2019 (inches*)

-1

+3

+4

0

-4

Difference from average water level for Jul 12, 2018 (inches*)

+7

+15

+13

+12

+29

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

+13

+31

+33

+32

+32

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

0

-1

+5

+4

+5

Year of highest recorded monthly mean

1950

1986

1986

1986

2017

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

+34

+63

+61

+67

+66

Year of lowest recorded monthly mean

1926

1964

1934

1934

1934

Projected net change in levels by Aug 12, 2019 (inches)

0

0

-3

-5

-10

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, 1918-2018

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

Department of the Army

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Detroit District Great Lakes Homepage

Detroit District, Corps of Engineers

NOAA Center for Operational Oceanic Products and Services

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Weekly Great Lakes Water Levels

We do not have the ability to offer email updates at this time.  The Weekly Forecast of Great Lakes Water Levels is updated each week on Thursday afternoon or Friday morning depending on data availability.

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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.