MetService is warning of heavy rain and severe thunderstorms for the Taihape area on Tuesday, March 30.
The heavy rain warning runs from 1pm on Tuesday to 1pm on Wednesday. The severe thunderstorm watch starts at noon on Tuesday and finishes at 9pm Tuesday, meteorologist Dan Corrigan said.
The rain could be as heavy as 25mm to 40mm per hour, and will continue through Wednesday.
The whole Whanganui region is under a front coming in from the west. Periods of rain and thunderstorms are also predicted in the city.
Since Sunday, 36.2mm had already fallen in the city, Corrigan said. The rain had been lighter inland, with only 3.4mm falling at Waiouru during the same time and the Whanganui River level at Pipiriki rising only slightly.
That will change as the front rolls inland and the city and region get wetter. It's not cold though - top temperatures of 21C to 22C are predicted for the city.
"We are in quite a moist, warm northerly airflow, which has all the ingredients for thunderstorms," Corrigan said.
For the city and inland, it's looking like another wet day on Wednesday. Rain will continue as the low moves across the North Island.
It's followed by another low approaching from the west, with more rain and showers, and then a southerly change pushing up through the country.
That will bring strong southerly winds, but less rain.
"Going into Friday it looks like things are going to be a little bit better," Corrigan said.