Harmful Algal Bloom Forecasts

Lake Erie Harmful Algal Bloom Forecast

NOAA provides forecasts for seasonal blooms of cyanobacteria (blue-green algae) in Lake Erie, typically from July to October when warmer water creates favorable bloom conditions. Western Lake Erie has been plagued by an increase of HABs intensity over the past decade. These blooms consist of cyanobacteria or blue-green algae, which are capable of producing toxins that pose a risk to human and animal health, foul coastlines, and impact communities and businesses that depend on the lake. A combination of satellite image (for bloom location and extent), a forecasting and mixing model provide information on the current status of the bloom, forecasted position both at the surface and at depth, and toxicity from field samples. See individual products and our FAQs for more information.

Forecast Products


The Microcystis cyanobacteria bloom is present in western Lake Erie but cloud cover and winds prevent determining the area. The cyanobacteria is in patches offshore of the Ohio coast west of the Portage River. Also, Sandusky Bay has some traces of cyanobacteria. This is unrelated to western Lake Erie blooms. True color image has some sunglint, giving a silvery cast to parts of the lake. The seasonal forecast was issued June 30. No recent toxin data currently available. --Stumpf 07/26

The Lake Erie Forecast is operated by the National Centers for Coastal Ocean Science. Contact hab@noaa.gov for technical Questions. Last Updated: 2021-07-27 06 AM EDT


Observed Bloom Position

(from most recent satellite image)

Current satellite imagery from the Ocean Land Color Imager (OLCI) and true color imagery showing bloom location and extent.

Forecasted Bloom Position

(from modelling)

Forecasted extent and position of the bloom for a minimum of 96 hours, based on a combination of a hydrodynamic modeled currents and satellite imagery for initial bloom location.

Vertical Mixing Forecast

Forecast of the potential for mixing over the next at least 96 hours, to determine the likelihood that the bloom is at the surface or subsurface.

HAB Alerts

HABs in Lake Erie pose a risk to human and animal health, foul coastlines, and negatively impact communities and businesses. Sign up to receive Lake Erie HAB updates via email.

2021 Western Lake Erie Projections

The early season projection estimates bloom severity based on Maumee River discharge and modeled phosphorus loads. It is issued weekly from May until the seasonal forecast is announced. The final seasonal assessment will be completed by November 2021.


2021 Lake Erie Seasonal Forecast Event

The official seasonal forecast for Lake Erie was announced on June 30 during a live webinar hosted in collaboration with Ohio Sea Grant. Click here to view the NOAA press release.

Additional Resources

For other data on Lake Erie HABs, visit one of these websites:

For safety information on these blooms, visit the Ohio EPA website.