February was characterised by highs to the southeast of New Zealand, and more lows than normal over the north Tasman Sea. This produced more easterly winds than usual over the country. It was an extremely cloudy month for much of the country, due to both the moist easterly wind flows, and cooler than usual seas around New Zealand. Well below average temperatures were observed in eastern regions of both Islands, because of the onshore easterly winds, but it was a warmer than usual month for the West Coast. Rainfall for the month was rather patchy – with some very dry regions bordering extremely wet ones – in part because frequent thunderstorm activity during the month resulted in rather local rainfalls.
New Zealand Climate Update 153 – March 2012
What happened in February, how our climate outlook for the previous three months turned out, global and local sea temperatures, and our outlook for March to May.
Mature La Niña conditions are expected to dissipate in early autumn 2012. Lower pressures than normal are expected over the Tasman Sea for March to May as a whole, resulting in more frequent northeast winds than usual over the country.
Mature La Niña conditions are expected to dissipate in early autumn. Lower pressures than normal are expected over the Tasman Sea, resulting in more frequent northeast winds than usual over New Zealand. Seas around New Zealand are likely to be cooler than usual during autumn. Seasonal temperatures are likely to be average or below average in eastern areas of both Islands, and near average elsewhere. Autumn rainfall is likely to be normal or above normal in the north and east of the North Island, as well as the north of South Island, and near normal in all other regions.
The NIWA National Climate Centre's outlook for summer, December 2011 to February 2012, correctly indicated La Niña conditions, with weaker than normal westerlies over the North Island. East to northeast wind anomalies in fact did prevailed over the North Island, as per forecast.