HARMFUL ALGAL BLOOM MONITORING SYSTEM

Southwest Florida Intensification Forecast

The Southwest Florida Intensification Forecast provides an early warning of red tide initiation or intensification for coastal managers and decision makers. Red tide, also known as the dinoflagellate Karenia brevis, is harmful to marine animals and can cause respiratory distress in humans. Due to this health concern, beach closures may be necessary when coastal waters contain high concentrations of Karenia brevis. The Southwest Florida Intensification Forecast alerts coastal managers to potential red tide (Karenia brevis) bloom initiation or intensification along the southwest Florida coast, which provides advanced warning of a potential bloom and helps to minimize impacts to public health and coastal economies.


This model uses a nowcast/forecast system to predict potential harmful algal blooms initiation along the coast of Southwest Florida.

Onshore Karenia brevis (red tide) bloom intensificiation is unlikely along the Southwest Florida coast, as suggested by model results. Observed cell counts are at background levels with an onshore excursion of 1km. For technical model details and output, please see figures and explanations below.

How the Forecast Works

Click graphic to enlarge

During the early bloom period (typically each fall), Karenia brevis cells—which persist in the bottom waters offshore—can be moved onshore to the Southwest Florida coast by a process known as coastal upwelling. The graphics below demonstrate this process. Once near the coast, Karenia brevis cells can quickly reach levels that create a harmful algal bloom (HAB).

Image Caption: Downwelling - Southerly winds blowing along the Florida coast leads to downwelling. Offshore surface waters are moved onshore. Onshore bottom waters are moved offshore. Subsurface Karenia brevis cells are moved offshore resulting in low risk of bloom initiation.

Upwelling - Northerly winds blowing along the Florida coast leads to upwelling. Onshore surface waters are moved onshore. Subsurface Karenia brevis cells are moved onshore resulting in a high risk of bloom initiation.

For questions contact the NCCOS HAB Forecasting Team at hab@noaa.gov.