WeatherWatch NZ's August Climate Watch report is out now, highlighting the long forecasts for the final month of winter, how El Niño is tracking and an ongoing local marine heatwave affecting Aotearoa's climate.
Its Chief Executive Phil Duncan told REX host Dominic George that they expect to see pretty much the same weather patterns that the last few weeks of July brought.
"August is a lot like the last couple of weeks of July," he said.
"You might get the odd southerly coming through and then large dry spells coming through."
Because New Zealand commonly sits on the edge of a high-pressure belt, Duncan explained it's less likely significant rainfall will be a regular occurrence, but cloud and lighter showers blowing through will likely be more frequent.
While El Niño has not reached New Zealand just yet, the Australia Bureau of Meteorology and NIWA are expected to make an announcement regarding the significant weather event in the coming weeks, which falls into line with what Duncan said WeatherWatch has been predicting all year.
"Sometime around August/September, we were expecting some announcement."
For El Niño to be announced or declared, sea temperatures in the Americas need to be above normal, which he said is definitely happening, as well as the atmosphere coupling up with that temperature rise.
"Three or four degrees above average near Ecuador at the moment.
"The atmosphere has done that over towards the Americas, hasn't really done it yet on our side of the world and there's a reason for that."
Not only is there a marine heatwave carrying on around New Zealand where sea temperatures are a few degrees above normal, but warmer-than-average sea conditions in the Western Pacific up by the equator suggest that El Niño'simpact is not being felt in Aotearoa just yet.
"El Niño should be suppressing the sea temperatures in our part of the world and that isn't happening yet and so the atmosphere is not yet doing what you would normally expect, but we are starting to feel hints of it."
In terms of what to expect when El Niño does hit, Duncan said that based on historic data, the East Coast and some inland areas of New Zealand tend to dry out while the more Northern areas of the West Coast will be drier while the more Southern areas of the West Coast will likely be wetter.
He noted that long-term IBM data suggests there could still be significant variety in weather patterns throughout the rest of 2023.
Listen to the full chat between WeatherWatch NZ CEO and Dominic George above.