A front currently lying across the Tasman sea will move northward and form a new low pressure system near
Northland on Wednesday morning. This developing low is today creating for very calm, humid, conditions in the north and this has lead to fog affecting flights at both Hamilton and Auckland domestic airports this morning.
Today this fog will convert to afternoon cloud build ups with a few downpours forming inland in the upper North Island.
In the South Island a colder change is moving northwards with showers.
Some thunderstorms are likely in Canterbury, Marlborough, and eastern and northern parts of the North Island on Tuesday.
Despite some of the big forecasts for heavy rain and isolated thunderstorms in some regions this set up with a large but weak low will see breaks in the cloud allowing for sunny areas and dry or drizzly spells for others in the North Island.
– WeatherWatch.co.nz, an IBM and Weather Company business partner