People across NSW are being urged to stay out of the water this weekend with a one-in-50-year event bringing powerful winds, dangerous surf, and the risk of coastal erosion across the state's coastline.Last night, the coastal low stirred up 100km/h winds and an 11-metre swell, with a coastal hazard warning continuing to stretch down from Forster to past Eden.The hazardous surf warning is set to remain in place for the rest of the day, bringing dangerous surf forecasts, cold temperatures