May featured an above average month for precipitation in Green Bay by 2.81″. This was a common theme for many areas surrounding Lake Michigan-Huron. The added precipitation lead to high amounts of runoff flowing into the lake which was already running well above average. Below is a graphic showing the departure from mean for precipitation across the Midwest for May measured in inches. Areas in green indicate above average precipitation for the month. Yellow and orange areas are below average precipitation.
The long term average lake level on Lake Michigan-Huron in May is 579.04′. This May, the mean water level for the month was recorded at 581.94′. This set a new record for the month which was previously 581.63′ set in 1986. The water level for May in 2019 was at 581.28′. The lowest water level on the Lake Michigan-Huron system for May was 576.57′ set in 1964.
The image below shows the measured water levels so far this year on the Lake Michigan-Huron system indicated by the red line. The blue line shows the water levels throughout 2019. The black dashes on each month represent the maximum and minimum water levels for each of those months. Notice how every month this year the water level has been above the previous maximum. Green dots on the graph show the forecast mean water level for that month. Right now the forecast suggests water levels remaining near record levels through the summer and into the fall season.
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