The National Oceanic and Atmospheric Administration (NOAA) is projecting the algae bloom in western Lake Erie will be worse than last summer.
NOAA said severe harmful blue-green algal blooms are caused by phosphorus from the Maumee River pouring into the lake. The Maumee River flows from Indiana through Ohio and into Lake Erie.
"We project that the bloom will have a severity greater than 7 [much greater than 2018]," said the NOAA in a bulletin. "This forecast has not changed since last week."
NOAA added that rainfall is expected to decrease, but there is still uncertainty in the forecasts over local heavy rainfall in June. The U.S. agency said maximum severity could be reached with the possibility of more heavy rain over the next few weeks.
"Any bloom that develops will change with time and move with the wind," NOAA said.
The harmful algae bloom forecast bulletins are issued twice a week throughout the summer. The weekly forecasts identify which blooms are potentially harmful, where they are, how big they are, and where they're likely headed.
The early warning gives health officials, environmental managers and water treatment facility operators information to focus their testing and to guide beach and shellfish bed closures or water treatment in a more timely fashion. Early warnings also allow the seafood and tourism industries to minimize negative impacts.
NOAA said western Lake Erie has been plagued by an increase of harmful algal bloom intensity over the past decade.
The blue-green algae blooms are capable of producing toxins that pose a risk to human and animal health, mess up coastlines, and negatively affect communities and businesses that depend on the lake. A bloom in 2014 forced officials in Toledo, Ohio to shut down the drinking water system.