Beachgoers, Spear and Shoreline Fishers are advised to use caution and remain vigilant when venturing onto affected coastlines as powerful waves can put your life at risk.Locations to be affected: Reefs and exposed northern and north-facing coastlines with relatively shallow, gently to moderately sloping, nearshore areas.

Timing: until Saturday morning

Synopsis: Moderate long period swells are expected to reach the area and affect mainly northern and north-facing coastlines. The threat level to the life, livelihood, property and infrastructure of those using the affected coastlines is forecast to rise to high, with the potential for extensive impacts. These swells are expected to cause life-threatening surfs and rip currents for affected coastlines. A high surf advisory means that dangerous surfs of 2 to 3 metres or 6 to 10 feet will affect some coastlines in the advisory area, producing hazardous conditions.

Seas (significant wave heights): 1.5 to 2.4 metres (5 to 8 feet), occasionally or locally reaching near 3 metres (10 feet). Swell period: 9 to 13 seconds. Swells: North at 1.5 to 2.1 metres (5 to 7 feet) and occasionally higher.

Surfs (breaking swells): Over 2 metres (over 6 feet). These conditions are conducive for dangerous rip currents. Please note that surfs could be as much as twice the height of swells, depending on the bathymetry of the nearshore areas.

Coastal flooding: High tides combined with onshore wind and swell actions could result in localized coastal flooding and beach erosion.

Potential Impacts: Loss of life–strong currents that can carry even the strongest swimmers out to sea; injuries to beachgoers; beach erosion; sea water splashing onto low lying coastal roads; beach closures; localized disruptions to marine recreation and businesses; financial losses; damage to coral reefs; saltwater intrusion and disruptions to potable water from desalination. High surfs can knock spectators off exposed rocks and jetties.

Precautionary: Beachgoers, especially to the mainly affected coastlines, should be extremely cautious; bathe only where lifeguards are present or the sheltered, less affected beaches, mainly to the south. Extreme caution is also required by those using the affected non-beach or rocky coastlines.

Rip currents are powerful channels of water flowing quickly away from shore, which occur most often at low spots or breaks in the sandbar and near structures such as groins, jetties and piers. If caught in a rip current, relax and float. Don`t swim against the current. If able, swim in a direction following the shoreline. If unable to escape, face the shore and call or wave for help.

Forecaster: Dale Destin