New Zealand Climate Update 138 – December 2010

Anticyclones (‘highs’) dominated New Zealand’s climate during November 2010, producing record low November rainfall in many areas, and record November warmth for the South Island. This was the second month in a row in which rainfall has been extremely low for most regions, resulting in unusually dry soils for the time of year across northern and western regions of the North Island, and the northwest of the South Island. Severe soil moisture deficits (more than 130 mm of deficit) existed as at the end of the month in Northland, Auckland, parts of the Waikato, Nelson, the Lakes District and central Otago, with significant soil moisture deficits (more than 110 mm of deficit) elsewhere in the Waikato, Taupo, parts of the Manawatu and Gisborne, in Hawkes Bay and the Wairarapa, Marlborough, and parts of Canterbury.

During Dec-Feb, mean sea level pressures are likely to be above normal over and south of New Zealand. Temperatures are likely to be above average or average in all districts. Seasonal rainfall is likely to be below normal in the western South Island, normal or below normal in the north of the South Island, normal or above normal in the north and east of the North Island, and normal elsewhere.