Storms on the horizon
Weather trouble is brewing in the warm seas around New Zealand.
Forecasters say it’s only a matter of time before the marine heatwave in our corner of the Pacific turns an otherwise innocuous rain-bearing system into something more damaging.
While there are plenty of signs of change ahead, it is too early to pinpoint just when that weather will arrive here.
Many parts of New Zealand have dried out in the past month, due to persistent ridges of high pressure across and around the country.
With the exception of the west and far south of the South Island, no significant falls are expected to relieve the dry spell in the next week to 10 days.
MetService meteorologist Georgina Griffiths told The Press changes in the atmosphere were all around, but might take time to directly affect New Zealand.
The country was coming to the end of one of its broad weather patterns, which tended to last six weeks and rarely any longer.
‘‘We don’t normally hold a ridge across us for six weeks. But it looks like we are in for a pretty significant change this month.’’
Air pressure in the Tasman Sea and south of New Zealand was forecast to fall over the next two weeks. That would eventually bring more rain and please farmers, she said.
Blue Skies Weather forecaster Tony Trewinnard said ‘‘all the ingredients’’ were in place for wet and stormy weather across the country. But it just doesn’t want to happen at the moment.’’
Greater weather activity and energy in the atmosphere above the tropics and sub-tropics would eventually feed south towards New Zealand.
‘‘Also, the Tasman Sea is significantly warmer than usual. It shouldn’t take a great deal to push all that water vapour into any developing storm. All it needs is some kind of trigger to start the process.’’
From this weekend, for the next two weeks, the weather systems would be more active than in the past month, Trewinnard said.
WeatherWatch managing director Philip Duncan said: ‘‘There’s definitely trouble brewing. This is the biggest change I’ve seen in the tropics for six months. It’s a really big change and it’s happening really quickly.’’