Ynys Gwylan-fawr Swell ForecastUnited KingdomWLGwyneddYnys Gwylan-fawr1-Day3-Day5-Day Graph Plots Open in Graphs Swell Height and Direction Forecast NOAA WaveWatch III Swell Period Forecast NOAA WaveWatch IIIYnys Gwylan-fawr swell forecast issued today at 11:50 am. Next forecast at approx. 11:50 am.Get WillyWeather+ to remove ads