The legacy OPC website URL https://www.opc.ncep.noaa.gov permanently redirects to https://ocean.weather.gov. On or after July 9, 2019 the old URL will not work. Users must use https://ocean.weather.gov to access the OPC website. More information is available at https://www.weather.gov/media/notification/scn19-10opc_terminate.pdf.

Experimental Freezing Spray Guidance

Basin

Alaska  Atlantic  

Forecast hour

12  24  36  

Modified Overland (US algorithm in cm/hr) Stallabrass (Canadian algorithm in cm/hr)

The Overland* and Stallabrass images above depict the forecast ice accumulation rate (in cm/hour) at 12 hours, 24 hours, and 36 hours. The rate is an instantaneous forecast, not cumulative.

The guidance is based on the Global Forecast System (GFS) model data.

*More information on the Fetch Factor applied to Overland freezing spray algorithm (pdf).