The NCEP Marine Modeling and Analysis Branch (MMAB) Ensemble Global Ocean Wave Forecast System (EGOWaFS) provides five-day forecasts of global winds, wind wave and swell conditions in probabilistic terms. This product became available early in 2007 both through an NCEP non-operational web page and, for raw data, through FTP for use by marine forecasters at NWS WFOs and other locations. The data from the EGOWaFS can be used in a number of ways, including:* As input to probabilistic marine forecasts for wind waves and swell* As input to a local wave ensemble, such as Simulated Waves Nearshore (SWAN)* As input to develop probabilistic forecasts for rip current developmentThis webcast has been developed to introduce the EGOWaFS to the marine forecasting community. Topics discussed include:
- The unique basis for ensemble prediction of ocean waves
- Graphics of EGOWaFS product output and their interpretation
- Case examples showing examples of EGOWaFS, including:
- Potential for EGOWaFS forecast bias resulting from systematic errors in wind forcing,
- Use of EGOWaFS data to provide boundary conditions for local near-shore wave models, and
- Application of EGOWaFS data to create a probabilistic forecast for the occurrence of rip currents.
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1. Understand that the basis for ocean wave ensemble forecasting depends on the uncertainty in the near-surface wind forecasts, rather than uncertainty in the wave initial conditions.
2. Learn how to use the web-based graphics at NCEP for probabilistic forecasting of ocean waves.
3. Understand how bias in the wind forcing affects wave forecasts.
4. Learn potential uses for the wave ensemble forecasts, including local near-shore wave models and probabilistic forecasts of rip current.
NCEP, WaveWatch3, ensemble, Wave Ensemble, probabilities, significant wave height, primary wave height, secondary wave height, significant wave period, primary wave period, secondary wave period, probability of exceedance, ensemble wind forcing, marine prediction, SWAN model, ensemble mean and spread, spaghetti diagrams, local area models, rip currents, rip current forecasts, probabilistic forecasting, GFS ensemble, medium range ensemble forecast, ocean wave forecasts, ocean waves, probabilistic rip current forecasts
July 2014: The wave ensemble was made operational in 2006, and this lesson was created in 2007. Changes since that time include
- increase in ensemble membership from 10 to 20
Retaining unique 6-hour hindcasts for each member rather than using the same starting point to increase ensemble spread
Increasing forecast length from 120 to 180 hours
Multiple changes in wave model physics.