A southwesterly wind flow over the country is typically followed by showers, Mose says.
"Those southwesterly winds are going to be quite strong through the likes of Auckland and we are expecting a gale southerly for Wellington later this morning."
Thunderstorms are also forecast for some areas.
"The risk area covers Nelson, Buller and Marlborough.
"And in the North Island Wellington, Kapiti, Wairarapa, Hawke's Bay and Gisborne," Mose says.
Temperatures in the North Island will stay typically warm for this time of year with Auckland's high forecast for 20C. But in the south they are set to drop.
"In the South Island it is going to be a bit cooler."
Forecast for today
Auckland: A few showers, mainly in the morning. Southwesterly wind. High 20C Low 14C
Hamilton: Few showers, clear to fine spells afternoon. Southwesterly. High 20C Low 7C
Napier: Few showers, chance heavy/thunder afternoon. Southerly change. High 24C Low 10C
Wellington: Showers develop morning, chance heavy/thunder. Strong southerly. High 17C Low 10C
Nelson: Few afternoon and evening showers, chance heavy/hail. Strong southwesterly. High 20C Low 7C
Christchurch: Morning rain to cloudy periods and odd shower. Strong Southwesterly. High 15C Low 6C
Queenstown: Chance morning shower, then becoming fine. Fresh southerly. High 15C Low 5C
