Expect this spring to be like the real thing
After record-setting seasons, spring is expected to be . . . well, pretty much like spring. But be warned: an El Nino summer approaches.
Niwa’s latest report said despite a continued slow warming of ocean surface temperatures in the Pacific, July witnessed a slight weakening of the El Nino-like signals that emerged in June.
‘‘Most notably in the subsurface ocean and in the atmosphere,’’ Niwa meteorologist Ben Noll says.
‘‘However, intra-seasonal activity that recently developed in the far western Pacific might tip the system back to a more El Nino-like state in the next few weeks.’’
Niwa’s climate outlook for spring forecasts near normal rainfall for the country with temperatures near average in the North Island, but above average in the South Island.
From August to October soil moisture levels and river flows are forecast to be near normal in the north and east of the North Island.
However, in
South Island, the east of the Niwa forecast below normal soil moisture levels and river flows.
‘‘There will inevitably be wet and dry days, and hot and cold days, within a season. The exact range in temperature and rainfall within each of the three categories varies with location and season.’’
However, it could be the calm before the storm as the probability for El Nino conditions increases as we approach summer in the southern hemisphere – Niwa says there is a 78 per cent chance for El Nino conditions from February to April 2019.
The strength and characteristics of this event – if it eventuates – remain uncertain, but indications are it is unlikely to be strong.
What is El Nino?
In New Zealand, it’s a game of two halves. With the east and west coasts in both islands separated by mountain ranges, each coast will have its own summer experience. Strong winds from the west will bring hot and dry weather to the east coast, and it will be wet, wet, wet on the West Coast.
It also means the warmest months will be January and February. December is more likely to be on the cooler side.
It does not guarantee a drought for the east coast, but it is more likely to occur than in a non-El Nino summer.