Outlook for winter - take a guess
By JOHN HENZELL - The Press | Saturday, 2 June 2007
Want proof of the South Island's bizarre weather?
The first day of winter yesterday was more than six degrees warmer in Christchurch than the first day of last summer.
On December 1 last year, the South Island's east coast was taking shelter from southerly showers, ensuring the MetService's thermometer at Christchurch Airport failed to reach 14deg and making the icebergs off the Canterbury coast seem appropriate.
Yesterday, a nor'wester prompted balmy conditions and people wandering around Cathedral Square in their shirt sleeves as the same thermometer topped out at 20.2deg.
MetService weather ambassador Bob McDavitt said Mainlanders might have to get used to topsy-turvy seasons because the aberrant currents that brought chilly water and those rogue icebergs from Antarctica to New Zealand were forecast to become more common.
"The icebergs last summer were indicative of melt water that comes up from Antarctica. It's why the sea surface temperatures were so cool last summer," he said.
"There are only two places around the planet where Antarctic melt water heads north. One is east of New Zealand, and the other is up by South Africa.
"It doesn't bother them because they're too far north."
He said research indicated a trend towards New Zealand getting more of the Antarctic melt water currents and fewer going towards South Africa.
The currents do not operate in the same way in winter because Antarctica refreezes.
However, McDavitt said the balmy temperatures had more to do with the late continuation of the high-pressure systems than on the sea temperatures.
"There were three big high-pressure systems moving across the South Island and they kept the south-westerlies away. It's a typical April weather pattern, and it's unusual for them to extend until May.
"It won't extend into June because there's a south-westerly due to arrive for Queen's Birthday weekend and you'll notice temperatures dropping quite markedly."
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