"Rain could be briefly heavy, as strong north easterly winds start changing.
"Once the winds turn southerly the rain will start clearing out and behind that there will just be isolated showers and it should be becoming fine."
The Metservice website indicates that rainfall is expected to ease by 1pm on Friday.
"Winds will start turn westerly in the evening after the southerly comes through," Clark said.
Saturday promised cloudy periods, Clarke said, with patchy light rain in inland areas and high ground.
"For most people in the city it'll just be cloudy periods throughout the day, with westerlies changing south east in the late afternoon.
"Sunday is looking fine, with light winds.
"Generally it's looking like a pretty good weekend for Whanganui, which I'm sure is music to a lot of people's ears."