As well as thunder and lightning, torrential rain of between 25-40 mm per hour is expected to lead to flooding especially in low-lying areas such as streams, rivers or narrow valleys.
MetService is warning driving conditions will also be hazardous with surface flooding and poor visibility.
The alert includes Waikato, Waitomo, Taumarunui, Taupō, Hawke’s Bay, Taihape, Wanganui, Manawatū, Tararua and Wairarapa.
Civil Defence in affected regions are also alerting communities about the potential for a stormy six hours.
Niwa Weather said waves of showers and thunderstorms would impact a large part of New Zealand today, with downpours likely.
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The storms come as New Zealand experiences an unusually warm month with the mercury soaring past 30C in the South Island and all but one climate station recording above or well above average temperatures.
Yesterday Niwa said around 60 locations across the country were tracking for the warmest or near warmest November on record.
Apart from a brief cooler spell next week, the country was expected to bathe in the unusual warmth for the rest of the month.
