Warning: GALE warning for CONWAY for Friday

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: Westerly 10 knots, tending northerly for a time this afternoon. Changing southwest 20 knots gusting 30 knots at night. Slight sea becoming moderate tonight. Fine and cloudy periods, fair visibility in brief overnight showers. Friday: Southwest 20 knots gusting 30 knots rising to 30 knots gusting 40 knots in the afternoon. Moderate sea becoming rough in the afternoon. Cloudy periods.

Outlook: Outlook until midnight Monday: Saturday: Southwest 25 knots, easing to 15 knots in the morning, 10 knots in the afternoon, then dying out at night. Becoming fine. Sunday: Variable 10 knots. Mainly fine, chance late shower. Monday: Southwest 10 knots, tending northeast 10 knots. Mainly fine.

Swell: Swell forecast to midnight Monday: Southeast half a metre, rising to 1 metre for a time on Friday and early Saturday.

High tide at Lyttelton
Time: 2:08pm Thursday 17 May 2012 - Height: 2.2m
Time: 2:29am Friday 18 May 2012 - Height: 2.1m