A former Kiwi weather presenter has defended MetService after its forecast failed to predict the extreme rainfall that led to deadly flooding in Auckland earlier this year.
Jim Hickey said the Auckland Anniversary flooding was a "freak event" and an "unusual storm" that was hard to predict.
Four people died due to the Auckland Anniversary flooding which caused around $3.5 billion in damages.
MetService has come under fire after an internal review was critical of its performance during the Auckland anniversary storm, branding it poor.
Its weather modelling systems did not forecast the amount of rainfall or degree of severe flooding caused by the deluge.
It has led to questions about whether better weather forecasting methods could've saved lives.
Hickey appeared on AM on Tuesday to discuss the findings and was quick to defend the forecasting agency.
He told AM co-host Ryan Bridge he has sympathy for MetService as the deluge was a "freak event".
"This was a really unusual storm, both in its tardiness and also in its haste and if we think back, I recall watching the forecast a day or two earlier and there was a tropical low coming down," he said.
"There was the potential spoken on air about the possibility of heavy rain across the upper North Island but of course, as it transpired, it was far more savage than that."
Hickey said the flooding was caused by the combination of two weather juggernauts that "locked horns".
"It was a large anti-cyclone parked just to the east of the South Island and as we all know, they come with fine weather, they're a large bubble of stable air and stoic - they won't move for other weather systems," he said.
"Then a former tropical cyclone came down into the Pacific with its entrails of warm air coming right out of the Pacific zone, it was packed with water vapour. The low, instead of tracking across the top of the of the North Island as they traditionally do in these circumstances, the high blocked it. It was it was a classic blocking high situation.
"So this particular low stopped in situ and of course the warmer the air the more water vapour it soaks up. So this thing brought down this incredible amount of water vapour... and it was a beast that fed itself."
He told AM he isn't willing to point blame to anyone but said the chain of command was fractured.
"There are so many things here, where do we start? Do we start with the tropical Pacific forecasting zone. Do we look at the metropolis of Auckland and it's its safety programs or protocols around this. Do we go to MetService?
"There was a tardiness because the chain of command was kind of fractured no one made a call and that was the problem, but the weather system, it was a freak event and Auckland, of course, had had record amounts of rain unseen for decades."
Now that the Auckland Anniversary flooding has happened, Hickey believes MetService will learn from it and will be better prepared for a similar event in the future.
He added MetService has an incredibly high accuracy rate but that doesn't stop people from still blaming them when they're wrong.
"MetService has got a really good record and the accuracy record over the decades I was there was in excess of 95 percent. When you look at the variability in New Zealand's weather, the funnelling effect of Cook Strait, the crashing zone between highs and lows, the disproportionately high mountains for the size of our country, it's a can of worms to try and forecast for accurately," he said.
"What people do remember is the 5 percent of the time that it's wrong and that's when the hammer comes down."
MetService chief executive Stephen Hunt said the weather behaved differently from how it had in the past for the Auckland flooding.
Hunt said the review will make sure MetService learns from the past and adapts to the changing climate around the world.
"As we're seeing around the world - with climate change affecting traditional weather patterns in different ways and more extreme weather becoming more frequent and more intense - that such an occurrence in New Zealand naturally exposes gaps and opportunities in systems that we've had for some time," Hunt told RNZ
"We're continuously learning and evolving our systems, which have served us very well in the past, but now we have to adapt and now we have to respond to that change in climate to make sure we can continue continually serve New Zealand best."
Watch the full interview with Jim Hickey in the video above.
