Locations to be affected: Especially, open waters on the Atlantic sides of the islands out to 20 nautical miles.

Timing: Wednesday night until Friday.

Synopsis: A combination of wind waves and wind swells is expected to cause hazardous seas, especially on the Atlantic sides of the islands. The threat level to the life, livelihood, property and infrastructure of mariners is forecast to rise to moderate to high with the potential for significant to extensive impacts. A small craft advisory means that wind speeds of 21 to 33 knots and or wind waves and or wind swells of 7 feet or greater are occurring or imminent. A warning may be required late Thursday into Friday.

Winds over open waters: East at 28 to 46 km/h (15 to 25 knots; 17 to 29 mph), with strong gusts to 72 km/h (39 knots; 45 mph).

Seas (significant wave heights): 2.1 to 3.7 metres(7 to 12 feet), occasionally or locally reaching near 4.6 metres (15 feet). Wind waves and or wind swells of 1.8 to 2.7 metres or 6 to 9 feet and occasionally higher. The dominant wind-wave period is 6 to 9 seconds. The highest seas are likely late Thursday afternoon into Friday morning, at which time, a warning may be required.

Potential Impacts: Loss of life at sea; injuries to mariners; capsize or damage or loss of vessels and marine equipment; financial losses; disruption of fisheries and scarcity of fish products and disruption to marine transportation.

Forecaster: Dale Destin