Warning: GALE warning for COOK GALE warning for STEPHENS

Situation: A strong southwest flow over New Zealand weakens on Saturday as a narrow ridge moves onto the country from the Tasman Sea. A trough crosses the South Island on Sunday and the North Island on Monday, followed by another ridge.

Forecast: Strong wind advisory. Thursday: Northerly 10 knots becoming northwest 15 knots this afternoon and rising to 20 knots gusting 30 knots tonight. Slight sea becoming moderate tonight. Fine weather. Friday: Northwest 20 knots gusting 30 knots changing southwest 20 knots gusting 30 knots knots early morning then rising to 30 knots gusting 40 knots in the evening. Moderate sea becoming rough in the evening. Fine and cloudy periods.

Outlook: Outlook until midnight Monday: Saturday: Southwest 25 knots, easing to 15 knots in the afternoon, dying out overnight. Mainly fine, chance shower. Sunday: Northerly 10 knots developing in the morning, dying out at night. Becoming cloudy, few showers developing. Monday: Southerly 10 knots. Becoming fine.

Swell: Swell forecast to midnight Monday: Northwest half a metre, rising to 2 metres overnight tonight, gradually easing to half a metre on Friday, dying out on Saturday.

High tide at Karehana Bay
Time: 7:30pm Thursday 17 May 2012 - Height: 1.2m
Time: 7:40am Friday 18 May 2012 - Height: 1.2m