The most recent example of this was this week, when heavy rain, potential flooding and severe gale-force winds warnings were in place for the Bay of Plenty.
The Bay of Plenty and Rotorua were forecast to get 90 and 110mm of rain respectively between 9pm on Tuesday and 6pm on Wednesday, expected to peak at rates of 10 to 20 mm/h yesterday afternoon.
Severe south to southwest gale gusts were expected to reach 120km/h in exposed places around the region, and damaging gusts of up to 140km/h yesterday east of Whakatāne.
"The system was expected to track along the coast of the North Island and bring significant rain to the area. That's what the computer modelling suggested earlier."
He said weather warnings were released through a collaboration of weather modelling with local council hydrologists.
The meteorological modelling told how much rain would fall and the hydrological modelling was about what interaction the rain would have once it hit the ground, he said.
James said the heavy rain was expected to be over the Bay of Plenty but was further east than the modelling predicted. That meant the rain fell over the sea, and it wasn't as bad for locals as initially thought.
"Thankfully ... the Bay of Plenty has been spared."
Wednesday evening update: MetService New Zealand has cancelled the Strong Wind Warning that was in place for the Bay of Plenty and Rotorua. Have a safe evening everyone.
Posted by Bay of Plenty Civil Defence on Wednesday, April 13, 2022
An Emergency Management Bay of Plenty spokeswoman said it relied on meteorological experts from MetService for weather information.
"If they consider a weather event has the potential to have severe effects, we need to take that seriously."
She said it was part of the regional and national arrangement with MetService to share weather warnings and watches as soon as they were issued.
She said with New Zealand being a relatively narrow strip of land in the middle of the ocean, one or two degrees in the change of course for a storm made a big difference.
When asked how the agency weighed up informing people about the potential risk of a severe weather event with the risk of it not happening and losing public trust, she said it never publicised anything unless it was backed up by evidence.
"Sometimes it will turn out better than expected, but our priority is making sure people know what is likely to happen and what they can do to best protect themselves, their whānau and their property."
She said none of the advice published in the days before ex-cyclone Fili reaching New Zealand would have put people in a worse-off position.
"Things like keeping an eye on traffic conditions and making sure you know where your emergency supplies are is always good advice."
She said weather events were easier to see coming unlike earthquakes, tsunami and eruptions, and thinking about what was needed ahead of a storm could help prepare for something less easy to anticipate.
Bay of Plenty Regional Council integrated catchments general manager Chris Ingle said ensuring public safety was a key driver for its flood management work.
He said the team assessed each warning as it came through against a number of other measures.
This included data from river levels and rainfall monitoring stations, the weather experienced previously, and other information received from staff in the field.
Rotorua Lakes Council communications manager Ingrid Tiriana said it generally communicated significant forecasted weather events when upgraded by MetService from watch to a warning.
She said there was always the potential for weather to change.
"That is the nature of weather. We think the community understands that this is the case and that it is better to be prepared than to get caught out.
"These weather events are becoming more frequent and highlight the need for everyone to be prepared in case of a significant event."
The latest information from MetService and BOP Civil Defence Emergency Management was shared.
The team also took advice from the council's civil defence staff about anything specific to the area that needed to be communicated and provided updates as needed.
