Medium-range ice forecasting using the GFS and the Great Lakes Operational Forecast System (GLOFS)

Real-time and forecasted ice information in the Great Lakes is critical for essential operations, such as ice breaking, commercial navigation, search and rescue, and oil spill response. Existing forecast products for the lakes are not available for medium-range time horizons (5-16 days out), yet they could provide important information for decision making, particularly for ice breaking and spill responses. In addition, Great Lakes ice forecasts at these timescales could be important for Medium-Range Weather (MRW) forecasting. However, the skill of existing operational products in predicting ice conditions at MRW timescales is not currently known. This project aims to determine how well ice and hydrodynamic forecasts from a coupled ocean-ice model (FVCOM-CICE) perform for MRW forecast horizons. MRW forecasts of ice and temperature using NOAA’s Great Lakes Operational Forecast System (GLOFS) will be driven by NOAA’s Global Forecast System (GFS) and compared to observed conditions from the National Ice Center (NIC). Simulations were carried out for the 2022 ice season, using 8 different MRW (16-day) forecast periods. Forecast results were compared to baseline observations of meteorology and nowcast ice conditions using standard skill assessment metrics. Results show the potential for MRW ice forecasts in the Great Lakes. These findings could inform the extension of existing Great Lakes operational models and the potential of lake-atmosphere coupling for the Unified Forecast System (UFS).