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It was a dramatic run of weather for the Hibiscus Coast over the Christmas and New Year period, with thunderstorms, hail and highly localised downpours breaking up what was otherwise a warm, early-summer pattern, Metservice Meteorologist Lewis Ferris says.
The most notable activity occurred around January 2 and 3, when a burst of thunderstorms tracked across the North Island, bringing lightning, short sharp rain and isolated hail to some Coast suburbs, while others remained largely dry.
Ferris says the storms were driven by a specific set of atmospheric conditions rather than random summer instability.
“Thunderstorms don’t just happen randomly and in New Zealand they aren’t an everyday occurrence,” Ferris says. There are usually a few ingredients required to form cumulonimbus clouds (the ones that produce lightning), in this case it was something referred to as a ‘cold pool’.”
This occurs when colder than usual air is around 5km up in the atmosphere.
“This area of cold air over the warm, humid surface air causes the air to rise (much like steam over a boiling pot of water). This rising air cools, water vapour condenses into clouds, then rain. Tiny pieces of hail form in cumulonimbus clouds which bump into each other as they rise and fall – this is what can bring about the separation of electric charges needed to produce lightning.”
For residents, the impact was uneven.
That’s the challenge with thunderstorm rainfall, Ferris says. “That type of rain can be quite hit or miss. Someone may have filled their tank while a friend on the opposite side of town may have had very little.”
Several suburbs reported brief hail showers during the storms, though no serious damage was recorded on the Coast. The hailstones were generally small and short-lived, forming high in the storm clouds before melting as conditions eased.
Aside from those storm days, the Christmas break delivered generally settled weather, with daytime temperatures hovering slightly above seasonal averages and plenty of dry spells for beachgoers and holiday events.
Looking ahead, the immediate forecast suggests a relatively calm pattern will continue through the coming week, with warm days and lighter winds. However, Ferris says this is the time of year when inland afternoon showers begin to develop more frequently.
“Keep an eye on weather from around the middle of next week though, as current weather models have some rain likely coming your way,” Ferris says.
For now, monitor daily MetService forecasts, particularly as summer storms can develop quickly and affect areas very differently.
While the Coast avoided severe weather over the holidays, the recent thunderstorms were a reminder that summer rain often arrives in bursts rather than steady systems, making preparation and monitoring essential, especially for those reliant on rainwater tank supply.
