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Weekly Forecast

ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

May 24, 2019

 

WEATHER CONDITIONS

Wet conditions continued over the past week, with all areas of the basin receiving 0.25-3 inches of precipitation. The northern portion of the basin and Lake Superior saw a particularly heavy precipitation of 3 inches last week, which is more than 1 inch above normal. Higher than normal precipitation is expected to continue into the next week. Heavy rain and thunderstorms are predicted for Friday and Saturday, with rain continuing into the week. Total precipitation is expected to be between 0.5-3 inches for the Great Lakes Basin with the heaviest rain falls centered on and around Lake Michigan. Heavy rains and high water levels may result in more flooding in the Great Lakes Basin, particularly near Green Bay. Temperatures remained on the lower end of historic averages last week between the 50s and mid-70s, with a few spikes into the 80s. Temperatures are predicted to remain near average for the following week, with temperatures in the mid-60s to 70s, peaking into the 80s on Saturday.

LAKE LEVEL CONDITIONS

Heavy precipitation and high flows have continued to contribute to rising lake levels. Since the previous month, Lakes St. Clair, Superior, Michigan-Huron, and Erie have risen 5, 6, 7, and 8 inches respectively. Lake Ontario has risen 21 inches since April. All lakes are currently experiencing higher water levels than this time last year, with a range of 7 to 12 additional inches for Lakes Superior, Michigan-Huron, St. Clair, and Erie. Lake Ontario is currently 20 inches higher than the previous year’s level. For the month of June, Lake Superior is predicted to rise 3 inches and Lake Michigan-Huron is predicted to rise 2 inches. Lake St. Clair is predicted to have no water level change, while Lake Erie and Ontario are expected to fall 2 inches and 1 inch respectively. Lakes Superior, St. Clair, and Erie are all currently above record monthly highs by 2 to 5 inches, while Lake Ontario is tied for its record monthly high and Lake Michigan-Huron is 2 inches below its record high. See our Daily Levels web page for more water level information.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

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

ALERTS

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 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 May 24, 2019 (feet)

603.02

581.43

577.07

574.48

248.72

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+23

+47

+57

+63

+65

Difference from average water level for Apr 24, 2019 (inches*)

+6

+7

+5

+8

+21

Difference from average water level for May 24, 2018 (inches*)

+12

+11

+7

+7

+20

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

+17

+29

+30

+31

+31

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

+2

-2

+2

+5

0

Year of highest recorded monthly mean

1986

1986

1986

1986

2017

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

+41

+58

+58

+65

+67

Year of lowest recorded monthly mean

1926

1964

1934

1934

1935

Projected change in levels by Jun 24, 2019 (inches)

+3

+2

0

-2

-1

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

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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.