Heatwave: Scientist tips a scorcher

Temperatures on the east coast of New Zealand could reach 40 degrees today and tomorrow, according to a climate scientist.

The weather has hit 40 twice in the country's history - Hawkes Bay authorities hope it won't last long and are on alert for a possible drought.

Dr Jim Salinger said the conditions were ripe for the mercury to reach the high 30s and even 40s on the eastern side of New Zealand. The conditions this week were very similar to that of a heatwave.

"Normally end of January, start of February is when we get the hottest temperatures of summer ... the atmospheric stew is set up nicely for us to get high temperatures over the next few days," he said.

A big high sitting to the east of the country, a large warm anticyclone parked near the Chatham Islands and the tail-end of Cyclone Oswald are all pushing up the temperatures. If New Zealand was ever going to break its record temperature, it would be now, Dr Salinger said.

"The conditions are set to create warm south-westerlies in the east of the South Island and southern North Island," he said.

New Zealand's hottest recorded temperature is 42C in Rangiora on February 7, 1973, followed by 40.3C on February 6, 2011, in Timaru.

Auckland's hottest recorded temperature is 32.4 on February 12, 2009, at Whenuapai Air Base. It equalled the city's previous high, recorded in the Auckland Domain in February 137 years earlier, in 1872.

The city is expected to reach a high of 25C today and highs of 26C tomorrow through until Saturday.

MetService forecaster Ian Gall doubted temperatures would top 35C, saying there were "modifying factors in the coastal places" such as sea breezes. It normally took a north-westerly to bring temperatures above the mid-30s, he said.

WeatherWatch head analyst Philip Duncan said he could not see temperatures reaching the 40C mark. Timaru's 40.3C "came about from a hot north-westerly that came right off the Australian desert", he said. "I don't think it's going to happen."

Hawkes Bay is on drought watch after receiving just half its normal January rainfall after a dry December.

Ministry of Primary Industries spokesman Stuart Anderson said an official drought was when it had economic, environmental and social impacts on farming businesses, families and the wider community.

The warm dry weather has proved a boon for vineyards and orchardists but Otane grower Hugh Ritchie was philosophical about non-irrigated crops suffering.

"Last year we had just as many disasters with the wet weather, so it's swings and roundabouts," he said.

NIWA data shows Kaitaia has had 4mm out of a normal 89mm for the month, Auckland 6mm compared with 61mm, Tauranga 4mm compared to 78mm, and Hamilton 11mm instead of 82mm.

Record sizzlers

42.4C Rangiora, February 7, 1973

40.3CTimaru, February 6, 2011

32.4C Auckland's hottest days February 12, 2009 (at Whenuapai Air Base) and in 1872 (At Auckland Domain)

- additional reporting: Hawke's Bay Today